Vitamin B12 Absorption: Methylcobalamin vs Cyanocobalamin

Showing 60 of 147 Cmax/Tmax/AUC values (human first). All 229 values are in /api/supplements/vitamin-b12.

1. Human Uhl W, Nolting A, Gallemann D, Hecht S, Kovar A. Changes in blood pressure after administration of hydroxocobalamin: relationship to changes in plasma cobalamins-(III) concentrations in healthy volunteers. Clinical toxicology (Philadelphia, Pa.). 2008;46(6):551-9; discussion 576-7. PMID 18584369. doi:10.1080/15563650701829763 PubMed · DOI · RCT (randomized, double-blind, placebo-controlled, single-dose, ascending dose groups; 3:1 hydroxocobalamin:placebo), n=136 randomized in parent trial; PK sub-study 56 planned (42 hydroxocobalamin, 14 placebo); 41 in PK population
2. Human Castelli MC, Friedman K, Sherry J, Brazzillo K, Genoble L, Bhargava P, Riley MG. Comparing the efficacy and tolerability of a new daily oral vitamin B12 formulation and intermittent intramuscular vitamin B12 in normalizing low cobalamin levels: a randomized, open-label, parallel-group study. Clinical therapeutics. 2011;33(3):358-371.e2. PMID 21600388. doi:10.1016/j.clinthera.2011.03.003 PubMed · DOI · RCT (open-label, parallel-group, multicenter, 60-day with 30-day extension), n=50 randomized; 48 completed
3. Human Castelli MC, Wong DF, Friedman K, Riley MG. Pharmacokinetics of oral cyanocobalamin formulated with sodium N-[8-(2-hydroxybenzoyl)amino]caprylate (SNAC): an open-label, randomized, single-dose, parallel-group study in healthy male subjects. Clinical therapeutics. 2011;33(7):934-45. PMID 21722960. doi:10.1016/j.clinthera.2011.05.088 PubMed · DOI · open-label, randomized, single-dose, parallel-group (4 arms; treatment A pilot dose range-finding arm completed 3 weeks before B, C, D), n=20
4. Human Devi S, Pasanna RM, Shamshuddin Z, Bhat K, Sivadas A, Mandal AK, Kurpad AV. Measuring vitamin B-12 bioavailability with [13C]-cyanocobalamin in humans. The American journal of clinical nutrition. 2020;112(6):1504-1515. PMID 32844171. doi:10.1093/ajcn/nqaa221 PubMed · DOI · open-label single-dose stable isotope PK studies (3 experiments), n=4 high-dose; 11 low-dose (one also in high-dose); 3 repeat after replenishment
5. Human Forsyth JC, Mueller PD, Becker CE, Osterloh J, Benowitz NL, Rumack BH, Hall AH. Hydroxocobalamin as a cyanide antidote: safety, efficacy and pharmacokinetics in heavily smoking normal volunteers. Journal of toxicology. Clinical toxicology. 1993;31(2):277-94. PMID 8492341. doi:10.3109/15563659309000395 PubMed · DOI · open-label, non-randomized sequential groups with saline placebo controls, n=15 (5 also served as placebo controls)

1. HumanThe ScinTwelve Study: Pharmacoscintigraphic Evaluation and Pharmacokinetic Assessment of a Vitamin B12 Sustained-Release Tablet in Healthy Human Subjects.
   Cureus, 2026 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
   PMID 42756790DOI 10.7759/cureus.114721PMC13584612 (free full text)
   Verification: full text read; no PK numbers matched
   • Key findings · abstract:BACKGROUND: Oral bioavailability of vitamin B12 is highly dependent on gastrointestinal transit and site-specific release, with optimal absorption occurring in the terminal ileum.
   • Key findings · abstract:OBJECTIVE: This study aimed to evaluate the in vivo disintegration pattern, gastric emptying, and gastrointestinal transit of a vitamin B12 sustained-release tablet using pharmacoscintigraphy and to correlate these findings with systemic bioavailability.
   • Key findings · abstract:Serum vitamin B12 levels were measured at predefined intervals up to 48 hours.
   • Key findings · abstract:Serum vitamin B12 levels peaked at eight hours (296.00 ± 94.65 pg/mL), indicatin[excerpt truncated in our database — see source]
2. HumanRapid Restoration of Circulating Vitamin B12 Levels by Using Oral Sucrosomial® Vitamin B12 in Metformin-Associated B12 Deficiency: Results from a Double-Blind, Placebo-Controlled Randomized Clinical Trial.
   Pharmaceutics, 2026 · Design: randomized; double-blind · n: n = 25 · full text (Europe PMC XML) + abstract · open access (gold)
   PMID 41754978DOI 10.3390/pharmaceutics18020237PMC12944164 (free full text)
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   • Key findings · abstract:Background/Objectives: Vitamin B12 deficiency is common in individuals with type 2 diabetes mellitus (T2DM) receiving long-term metformin therapy, primarily due to impaired intestinal absorption.
   • Key findings · abstract:A lipid-based Sucrosomial® delivery system has been shown to improve circulatory vitamin B12 levels in healthy adults with deficiency, and the present study evaluates its performance in the clinically challenging context of metformin-treated individuals with T2DM, a population characterized by pharmacologically impaired intestinal vitamin B12 absorption.
   • Key findings · abstract:Serum total vitamin B12 and holotranscobala[excerpt truncated in our database — see source]
   • Form comparison · full text, Section '3.1. Rapid and Sustained Increases in Ci':Consistent with these findings, post hoc comparisons (Figure 2A,B) revealed no significant difference between groups at baseline, whereas serum vitamin B12 concentrations were significantly higher in the Sucrosomial® Vitamin B12 group compared with placebo as early as 24 h after treatment initiation, corresponding to a 115% greater ratio of change (ROC) versus placebo.
   • Form comparison · full text, Section '3.2. Rapid Cumulative Incidence of Achie':Consistently, Cox proportional hazards regression demonstrated a significantly greater likelihood of achieving upper-normal laboratory reference range circulatory vitamin B12 concentrations in the Sucrosomial® Vitamin B12 group compared with placebo (hazard ratio [HR] = 14.19, 95% CI: 4.79–42.04; p < 0.0001).
   • Form comparison · full text, Section '3.3. Rapid and Sustained Increases in Ci':In contrast, circulatory HoloTC concentrations were significantly higher in the Sucrosomial® Vitamin B12 group compared with placebo from 1 week onward, corresponding to a 113% (ROC) at 1 week.
3. HumanVitamin B12 absorption and factors associated with the response to long-term oral B12 supplementation: a secondary analysis of data from a B12-deficient Indian rural community.
   Eur J Clin Nutr, 2026 · Design: randomized; double-blind · n: n = 109 · abstract (PubMed); full-text PDF saved · open access (green)
   PMID 42768083DOI 10.1038/s41430-026-01825-zPDF
   Verification: full-text auto-extracted verbatim snippets with location; needs human check
   • Key findings · abstract:BACKGROUND: The absorption of oral vitamin B12 (B-12) and predictors of its long-term supplementation are not well understood in populations with B-12 insufficiency.
   • Key findings · abstract:OBJECTIVE: In a secondary data analysis of a B-12 absorption study and a supplementation trial in a B-12 insufficient rural Indian community, we examined (i) the distribution of plasma holotranscobalamin (holoTC) responses during an absorption test, and (ii) predictors of B-12 status during long-term, oral supplementation with physiological and near-physiological doses of B-12.
   • Key findings · abstract:METHODS: Participants in the Pune Maternal Nutrit[excerpt truncated in our database — see source]
   • Relative bioavailability · full text, p.7:39.0 in fathers), and 23.0 pmol/L for the 2 µg dose (39.0 in children, 19.0 in mothers, 10.0 in fathers) (Table 1). Overall, plasma holoTC increased 4.8-fold with the 10 µg dose and 2.2-fold with the 2 µg dose; the rise was greater in children than in the parents (Table 1 and Fig. 2). Using Bor et al.’s 2004 criterion (rise in plasma holoTC < 15% and < 15 pmol/L after 3 doses of B-12) [12], 10% of
   • Relative bioavailability · full text, p.8:olate concentrations increased in those who received folic acid (Supplementary Table 2, Supplementary Fig. 2). At 12 months, the median B-12 rise was 1.9-fold (95% CI: 1.8–2.2) from baseline in the 10 µg group, compared to 1.5-fold (95% CI: 1.3–1.7) in the 2 µg group. Using the combined B-12 marker (cB12), the B-12 adequacy status remained stable in the placebo group (baseline 46.0% and 12 months
   • Food effect · full text, p.5:ospital & Research Centre, Pune. Standardised food and facilities were provided. Demographic details and anthropometric measurements were recorded. A fasting blood sample was collected (baseline), and a 10 µg (64 families) or 2 µg (44 families) B-12 (cyanocobalamin) capsules were administered under supervision every 6 h x 3 times. A fasting blood sample was collected the following morning (post-do
   • Food effect · full text, p.6:ldren’s baseline plasma B12 concentrations (below and above the median value of 188 pmol/L). The duration of supplementation was 12 months, and a non-fasting blood sample was collected at 4 and 12 months after starting supplementation to measure circulating B-12 concentrations. Compliance with B-12 supplements was assessed monthly by counting the unused capsules and as a percentage of the capsules
   • Form comparison · full text, p.5:generational trial [16] to reduce the primordial risk of diabesity in the population. The KEM Hospital Ethics Committee approved both studies (KEMHRC/VSP/Dir Off/EC/065; Project No. 067). The timeline of the B-12 absorption protocol [13] and B-12 supplementation trial [14] is summarized in Fig. 1. Absorption study protocol One hundred and nineteen families, from the follow-up in the extended PMNS,
   • Form comparison · full text, p.6:e- resistant strain of Lactobacillus leishmannii [17, 18] and a chloramphenicol-resistant strain of Lactobacillus casei I [19, 20], with inter-batch CVs of < 8% and < 7%, respectively. Plasma holoTC was measured using magnetic beads (microspheres) with an immobilized monoclonal antibody specific for human transcobalamin, followed by the conventional microbiological assay developed for cobalamin es
   • Form comparison · full text, p.8:e peak (average), width (variability), and shifts (comparing the effects of 2 and 10 µg B-12 doses). The peaks shift further to the right in children compared to parents, indicating a higher average rise for both doses. The width is smaller for the 2-µg dose than for the 10-µg dose, suggesting less variability, and the curves for the 10-µg dose are shifted to the right compared to the 2-µg dose, d
4. HumanNovel genetic variants associated with stable isotope-based vitamin B12 bioavailability measurements in healthy Indian adults.
   Am J Clin Nutr, 2025 · Design: stable-isotope · abstract only (PubMed) · closed/paywalled
   PMID 40840787DOI 10.1016/j.ajcnut.2025.08.005
   Verification: abstract-only auto-extract; unverified
   • Key findings · abstract:Despite adequate intake, vitamin B12 deficiency/insufficiency can arise due to interindividual differences in absorption and metabolism influenced by genetic factors, gastrointestinal health, and medications.
   • Key findings · abstract:Although previous studies have explored the genetic basis of circulating vitamin B12 concentration, they have not been validated using precise, stable, isotope-based measurements of vitamin B12 bioavailability.
   • Key findings · abstract:OBJECTIVES: To measure the plasma bioavailability of an oral dose of [13C]-labeled vitamin B12 (cyanocobalamin) using 2-compartment pharmacokinetic modeling and examine its ass[excerpt truncated in our database — see source]
   • Relative bioavailability · abstract:RESULTS: The mean measured vitamin B12 bioavailability was 52% ± 16%, demonstrating significant 4.4-fold variability.
   • Relative bioavailability · abstract:Bioavailability-PRS explained 72% (95% CI: 60%, 81%) of the variance in vitamin B12 bioavailability in the same cohort and 55% in a 3-fold cross-validation test.
5. HumanPhysiologically Based Pharmacokinetic Modeling of Vitamin B-12 Incorporating Mechanistic Absorption: An Example Application for Intake Estimation During Pregnancy.
   J Nutr, 2025 · Design: not stated · abstract only (PubMed) · closed/paywalled
   PMID 40750040DOI 10.1016/j.tjnut.2025.07.019
   Verification: abstract-only auto-extract; unverified
   • Key findings · abstract:Oral absorption of vitamin B-12 occurs through an intrinsic factor (IF)-dependent pathway at physiological intake amounts supplemented by passive diffusion at pharmacologic doses.
   • Key findings · abstract:Vitamin B-12 deficiency is a global public health concern, with certain populations such as older adults and pregnant women at higher risk.
   • Key findings · abstract:OBJECTIVES: This study aimed to develop a physiologically based pharmacokinetic (PBPK) model of vitamin B-12 absorption and apply it to evaluate intake requirements under altered physiological conditions.
   • Key findings · abstract:METHODS: A PBPK model incorporated key absorption mechanisms, includi[excerpt truncated in our database — see source]
6. HumanEffect of calcium supplementation on reversing metformin-based inhibition of vitamin B12 bioavailability in healthy adults using a [13C] cyanocobalamin tracer - A pilot study.
   Clin Nutr ESPEN, 2024 · Design: crossover; stable-isotope · n: n = 7 · abstract only (PubMed) · closed/paywalled
   PMID 38901951DOI 10.1016/j.clnesp.2024.04.024
   Verification: abstract-only auto-extract; unverified
   • Key findings · abstract:In the present study, we quantified the effect of metformin, and metformin co-administered with calcium on B12 absorption using a novel stable isotope [13C] cyanocobalamin tracer.
   • Key findings · abstract:METHODS: A pilot crossover study was conducted to estimate the bioavailability of B12 in healthy subjects, using [13C] cyanocobalamin as a tracer.
   • Key findings · abstract:In the study, [13C] cyanocobalamin was administered orally to the participants followed by hourly venous sampling to measure the concentration of the tracer and estimate bioavailability.
   • Key findings · abstract:The mean B12 bioavailability (±SD, n = 7) was 42.6 ± 10.2% for the control day ([excerpt truncated in our database — see source]
7. HumanComparative bioavailability study of supplemental oral Sucrosomial ® vs. oral conventional vitamin B12 in enhancing circulatory B12 levels in healthy deficient adults: a multicentre, double-blind randomized clinical trial.
   Front Nutr, 2024 · Design: randomized; double-blind · full text (Europe PMC XML) + abstract · open access (gold)
   PMID 39582666DOI 10.3389/fnut.2024.1493593PMC11581850 (free full text)PDF
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   • Key findings · abstract:Serum B12 levels were measured at baseline (day 0) and on days 1, 3, 5, and 7.
   • Key findings · abstract:RESULTS: Sucrosomial® B12 was significantly more effective than conventional B12 formulations in increasing and maintaining higher serum B12 levels across all time points.
   • Key findings · abstract:CONCLUSION: Sucrosomial® vitamin B12 demonstrated superior efficacy in rapidly and consistently elevating and maintaining higher circulatory B12 levels compared to conventional supplements.
   • Key findings · abstract:Its characteristic absorption mode and proven efficacy suggest it could effectively address B12 deficiency in a broad range of populations, including tho[excerpt truncated in our database — see source]
8. HumanSingle-blinded, stratified, dose ranging trial to assess pharmacokinetics and identify optimal dose of vitamin B12 in pregnancy in Tanzania.
   Gates Open Res, 2024 · Design: randomized · full text (Europe PMC XML) + abstract · open access (gold)
   PMID 41488590DOI 10.12688/gatesopenres.15991.2PMC12759048 (free full text)PDF
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   • Key findings · abstract:Primary endpoints include serum B12 concentrations, holotranscobalamin concentrations, and their ratio after four weeks of daily supplementation.
   • Key findings · abstract:We will answer questions about how pre supplementation vitamin B12 status and dosage impact vitamin B12 saturable absorption and steady-state over the course of four weeks.
   • Form comparison · full text, Section 'Explanation for the choice of comparator':One study in Bangladesh found that although pregnant women received a daily multivitamin with 2.6 µg B12 across pregnancy, there were still high rates of B12 deficiency (<150 pmol/L) in the third trimester compared to their early pregnancy, non-supplemented baseline 29 .
9. HumanEffect of roasted purple laver (nori) on vitamin B12 nutritional status of vegetarians: a dose-response trial.
   Eur J Nutr, 2024 · Design: randomized · full text (Europe PMC XML) + abstract · open access (hybrid)
   PMID 39352476DOI 10.1007/s00394-024-03505-9PMC11519184 (free full text)
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   • Key findings · abstract:PURPOSE: To investigate the bioavailability of vitamin B12 from nori and to evaluate the required dosage for improving vitamin B12 nutritional status in vegetarians not using supplements.
   • Key findings · abstract:The primary outcome was changes in vitamin B12 status as measured by serum vitamin B12, holotranscobalamin (holoTC), homocysteine (Hcy), and methylmalonic acid (MMA), and a combined score of these four markers (4cB12 score) during the four-week intervention.
   • Key findings · abstract:RESULTS: After adjusting for baseline status, nori consumption led to significant improvement in serum vitamin B12 (among-group P-value = 0.0029), ho[excerpt truncated in our database — see source]
   • Form comparison · full text, Section 'Changes in biochemical parameters throug':Compared with control group, low-dose (5 g nori) group showed significant improvement in serum vitamin B12 (lease square mean [95% CI] = + 59 [25, 93] pmol/L, P = 0.0014); holoTC (+ 28.2 [10.1, 46.3] pmol/L, P = 0.0035);
10. HumanThe Oral Bioavailability of Vitamin B12 at Different Doses in Healthy Indian Adults.
    Nutrients, 2024 · Design: randomized; crossover · full text (Europe PMC XML) + abstract · open access (gold)
    PMID 39683551DOI 10.3390/nu16234157PMC11643782 (free full text)
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    • Key findings · abstract:BACKGROUND/OBJECTIVES: The bioavailability of crystalline vitamin B12 (B12) through active absorption is reported to have a maximum capacity of 1.5-2.5 µg per dose.
    • Key findings · abstract:The present study aimed to determine the dose-dependency of active B12 absorption and to quantify its passive absorption at higher doses.
    • Key findings · abstract:METHODS: The dose-dependency of crystalline B12 bioavailability was determined in nine healthy adults, using oral [13C]-cyanocobalamin, in a cross-over design at doses of 2.5, 5, and 10 µg.
    • Key findings · abstract:Literature data from was added to the present study data in a meta-analysis of the relation between B[excerpt truncated in our database — see source]
    • Fractional absorption · full text, Section '3. Results':The maximum response of absolute bioavailability in the break-point analysis was found to be at 2.56 µg oral dose, where the maximum absorption was 1.2 µg.
    • Fractional absorption · full text, Section '5. Conclusions':When data from previous studies were added to the present study data, and a break-point analysis was performed on the bioavailability–dose relationship, it showed two phases, with a first phase up until a dose of 2.56 µg was reached, with a steep slope that signified an absorption of 43% of the administered dose, after which the slope was shallower, with an absorption of 1% of the administered dos
11. HumanKinetics of Cellular Cobalamin Uptake and Conversion: Comparison of Aquo/Hydroxocobalamin to Cyanocobalamin.
    Nutrients, 2024 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
    PMID 38337663DOI 10.3390/nu16030378PMC10857013 (free full text)
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    • Key findings · abstract:More HOCbl was accumulated over 4-48 h, but further extrapolation indicated similar uptake (>90%) for both vitamin forms.
    • Form comparison · full text, Section '3.1. Exploratory Tests of Cbl Uptake by ':The pilot assay showed a significant difference between the intracellular radioactivity when supplying the cells with CN[57Co]Cbl (≈29%) vs.
    • Form comparison · full text, Section '3.1. Exploratory Tests of Cbl Uptake by ':The same was the case for the residual radioactivity in the respective cell-free mediums (≈47% vs. ≈12%).
    • Form comparison · full text, Section '3.3. Intracellular Cbls and The Extracti':The material balance of radioactivity in the collected fraction vs. the injected sample corresponded to mean ± SEM = 81 ± 1% for CN[57Co]Cbl (n = 5) and 85 ± 3% for HO[57Co]Cbl (n = 5), probably reflecting a small loss in the injection loop.
12. HumanBioavailability and daily requirement of vitamin B12 in adult humans: an observational study of its colonic absorption and daily excretion as measured by [13C]-cyanocobalamin kinetics.
    Am J Clin Nutr, 2023 · Design: not stated · n: n = 11 · abstract only (PubMed) · open access (bronze)
    PMID 38044024DOI 10.1016/j.ajcnut.2023.08.020
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Extraileal absorption, such as from the colon, as well as reduced daily excretion, may be adaptive mechanisms to maintain B12 homeostasis with marginal intakes.
    • Key findings · abstract:OBJECTIVE: To measure the absorption of B12 from the small and large intestine, and its daily rate of excretion from the body, using a [13C]-cyanocobalamin tracer.
    • Key findings · abstract:METHODS: Oral B12 bioavailability was measured over 12 h after administration of [13C]-cyanocobalamin tracer (2.5 μg) in normal participants.
    • Key findings · abstract:The colonic B12 bioavailability was evaluated by direct instillation of [13C]-cyanocobalamin (5 μg) into the ascending colon. |[excerpt truncated in our database — see source]
    • Fractional absorption · abstract:CONCLUSIONS: B12 is absorbed in the human colon.
13. HumanMeasuring vitamin B-12 bioavailability with [13C]-cyanocobalamin in humans.
    Am J Clin Nutr, 2020 · Design: stable-isotope · n: n = 11 · abstract only (PubMed) · open access (bronze)
    PMID 32844171DOI 10.1093/ajcn/nqaa221
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The measurement of bioavailability of vitamin B-12 is etiologically important in deficiency but is limited due to the use of radioactive isotopes like [57Co]- or [14C]-cyanocobalamin.
    • Key findings · abstract:OBJECTIVES: The aim of this study was to measure the bioavailability of [13C]-cyanocobalamin in humans and to assess the effect of parenteral replenishment of vitamin B-12 on the bioavailability.
    • Key findings · abstract:After purification and mass spectrometry-based characterization, its oral bioavailability was measured in the fasted state with high and low oral doses, before and after parenteral replenishment of vitamin B-12 store[excerpt truncated in our database — see source]
    • Relative bioavailability · abstract:Parenteral replenishment of the vitamin B-12 store in deficient individuals prior to the measurement resulted in a 1.9-fold increase in bioavailability.
    • Food effect · abstract:After purification and mass spectrometry-based characterization, its oral bioavailability was measured in the fasted state with high and low oral doses, before and after parenteral replenishment of vitamin B-12 stores, from the kinetics of its plasma appearance in a 2-compartment model.
14. HumanRetention, stability, iron bioavailability and sensory evaluation of extruded rice fortified with iron, folic acid and vitamin B12.
    Matern Child Nutr, 2020 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
    PMID 33347722DOI 10.1111/mcn.12932PMC7752130 (free full text)
    Verification: full-text auto-extracted verbatim snippets with location; needs human check
    • Key findings · abstract:The objective of the present study is to assess the retention, stability and iron bioavailability from indigenously developed triple fortified rice (iron, folic acid and vitamin B12 ) during rinsing and different cooking methods.
    • Key findings · abstract:The retention of iron during rinsing with excess water was ≥90%, whereas folic acid and vitamin B12 levels were reduced by ~25% during rinsing.
    • Key findings · abstract:The dialyzable iron and ferritin synthesis in Caco-2 cells was significantly (P < .01) higher from fortified rice compared with unfortified rice.
    • Key findings · abstract:In addition, inclusion of ascorbic acid significantly (P < .01) increased[excerpt truncated in our database — see source]
    • Form comparison · full text, Section 'Retention and stability of nutrients dur':Interestingly, cooking of rice in electric or pressure cooker led to small additional decline in folic acid (~10–16%) but not vitamin B12 compared with rinsed rice, but the differences were not significant.
    • Form comparison · full text, Section 'Bioavailability of iron from fortified r':The percentage dialyzable iron from unfortified rice (16.66% ± 1.0) is significantly higher compared with fortified rice (4.54% ± 0.28) (Table 2).
15. HumanWolffia globosa-Mankai Plant-Based Protein Contains Bioactive Vitamin B12 and Is Well Absorbed in Humans.
    Nutrients, 2020 · Design: randomized · n: n = 294 · full text (Europe PMC XML) + abstract · open access (gold)
    PMID 33049929DOI 10.3390/nu12103067PMC7600829 (free full text)
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    • Key findings · abstract:We examined the presence of B12 in a cultivated strain of an aquatic plant: Wolffia globosa (Mankai), and predicted functional pathways using gut-bioreactor, and the effects of long-term Mankai consumption as a partial meat substitute, on serum B12 concentrations.
    • Key findings · abstract:We explored the effect of a green Mediterranean/low-meat diet, containing 100 g of frozen Mankai shake/day, on serum B12 levels during the 18-month DIRECT-PLUS (ID:NCT03020186) weight-loss trial, compared with control and Mediterranean diet groups.
    • Key findings · abstract:A higher abundance of 16S-rRNA gene amplicon sequences associated with a genome co[excerpt truncated in our database — see source]
    • Form comparison · full text, Section '3.2.2. The Effect of the Intervention on':Green-MED/low-meat: −3.9 ± 6.5%) compared with the HDG group (−0.6 ± 5.1%, p < 0.05 for both MEDs vs.
    • Form comparison · full text, Section '3.2.2. The Effect of the Intervention on':After 18 months, the HDG group had a non-significant 1.245 ± 126.5 pg/mL (+5.2%) change in serum vitamin B12 levels (p = 0.93 vs. baseline), while MED had a significant increase in serum vitamin B12 levels (32.6 ± 76.2 pg/mL (+9.9%); p < 0.001 vs. baseline) as well in group Green-MED/low-meat (48.8 ± 124.9 pg/mL (+15.4%); p < 0.001 vs. baseline).
16. HumanVitamin B12 Added as a Fortificant to Flour Retains High Bioavailability when Baked in Bread.
    Nucl Instrum Methods Phys Res B, 2019 · Design: not stated · n: 5 participants · abstract (PubMed); full-text PDF saved · open access (bronze)
    PMID 30555197DOI 10.1016/j.nimb.2018.05.042PMC6290905 (free full text)PDF
    Verification: full-text auto-extracted verbatim snippets with location; needs human check
    • Key findings · abstract:The purpose of this pilot study in five participants was to determine if fortification of flour with B12 produced a bread product with intact B12 still present and to determine if healthy elderly absorb sufficient B12 from bread fortified in this manner.
    • Key findings · abstract:Excess 14C first appeared in plasma 4 h after ingestion of the 14C fortified bread and plasma levels returned almost to background by 72 h.
    • Key findings · abstract:Measurement of 14C in plasma verified that the dose was absorbed into the systemic circulation.
    • Key findings · abstract:Bioavailability among the 5 participants, calculated by subtracting the sum of urinary and fecal 14C ex[excerpt truncated in our database — see source]
    • Fractional absorption · abstract:Measurement of 14C in plasma verified that the dose was absorbed into the systemic circulation.
    • Fractional absorption · abstract:Our pilot study shows that B12 added to bread as a fortificant in flour was absorbed as well as it is from endogenous food sources such as meat and fish.
    • Food effect · abstract:This study showed that when B12 is added as a fortificant to flour it survives the fermentation and baking processes, and retains ~ 50% bioavailability when fed in small doses to healthy subjects.
    • Food effect · full text, p.4:fed in small doses to healthy subjects. The Recommended Dietary Allowance of B12 for adults is 2.4 µg/d. This recommendation assumes that usual bioavailability of low doses of the vitamin in the crystalline form is 60%, while for the same amount in food
    • Food effect · full text, p.11:when the vitamin is added as a fortificant to flour it survives the fermentation and baking process, and retains its approx. 50% bioavailability when fed in small doses to healthy subjects. The Recommended Dietary Allowance for vitamin B12 established by the Institute of Medicine is 2.4 µg/d for adults [22]. This recommendation assumes that usual bioavailability of low doses of the vitamin in the
    • Form comparison · full text, p.9:This was probably primarily due to B12 bound to haptocorrin, which has a longer circulating plasma half-life than transcobalamin, approximately 10 d compared to 2 h [17]. The measurement of 14C in plasma served to verify that the dose was absorbed into the systemic circulation. The percentages of the dose radioactivity recovered in urine and stool homogenates are shown in Figure 4. The majority of
17. HumanComparative Bioavailability of Synthetic B12 and Dietary Vitamin B12 Present in Cow and Buffalo Milk: A Prospective Study in Lactovegetarian Indians.
    Nutrients, 2019 · Design: randomized · n: n = 22 · full text (Europe PMC XML) + abstract · open access (gold)
    PMID 30717112DOI 10.3390/nu11020304PMC6412291 (free full text)PDF
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    • Key findings · abstract:The baselines (median (min/max)) indicated a low B12 status: plasma B12 (116(51/314)) pmol/L, holotranscobalamin (holoTC) (30(7/119)) pmol/L, total homocysteine (Hcy) (24(10/118)) µmol/L, methylmalonic acid (MMA) (0.58(0.15/2.2)) µmol/L and combined B12 index (cB12) (-1.32 - (-3.12/+0.29)).
    • Key findings · abstract:The cyano-B12 treatment gave more total B12 in plasma at week one (+29 pmol/L, p = 0.004) but showed no further increase.
18. HumanHuman Intrinsic Factor Expression for Bioavailable Vitamin B12 Enrichment in Microalgae.
    Biology (Basel), 2018 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
    PMID 29463047DOI 10.3390/biology7010019PMC5872045 (free full text)PDF
    Verification: full text read; no PK numbers matched
    • Key findings · abstract:In this study, the suitability of using the human B12-binding protein intrinsic factor (IF) to enrich bioavailable B12 using microalgae was tested.
    • Key findings · abstract:Utilizing IF expression could be an efficient tool to generate B12-enriched microalgae in a controlled manner that is suitable for vegetarians and, potentially, more bioavailable for humans.
19. HumanLaparoscopy-assisted Proximal Gastrectomy with Double Tract Anastomosis Is Beneficial for Vitamin B12 and Iron Absorption.
    Anticancer Res, 2016 · Design: not stated · n: 17 patients · abstract only (PubMed) · open access (bronze)
    PMID 27630323DOI 10.21873/anticanres.11031
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Laboratory results, including hemoglobin, serum ferritin, serum iron and vitamin B12, were compared.
    • Key findings · abstract:CONCLUSION: LAPG-DTA has the advantages of allowing absorption of iron and vitamin B12 without reflux esophagitis in proximal early gastric cancer compared to LATG.
20. HumanIntestinal uptake and transport of vitamin B12-loaded soy protein nanoparticles.
    Pharm Res, 2015 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 25319101DOI 10.1007/s11095-014-1533-x
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:BACKGROUND: Intestinal absorption of vitamin B12 (VB12) is a major challenge in combating pernicious anemia due to intrinsic factor (IF) deficiency.
    • Key findings · abstract:PURPOSE: The aim of this study was to explore the feasibility of using soy protein isolates (SPI) nanoparticles to improve the intestinal transport and absorption of VB12.
    • Key findings · abstract:The intestinal uptake and transport mechanisms of SPI nanoparticles for VB12 delivery were investigated and related to particle size.
    • Key findings · abstract:The intestinal transport of VB12, assessed using rodent jejunum in Ussing chambers, was improved up to 4-fold after being encapsulated into[excerpt truncated in our database — see source]
    • Relative bioavailability · abstract:The intestinal transport of VB12, assessed using rodent jejunum in Ussing chambers, was improved up to 4-fold after being encapsulated into 30 nm SPI nanoparticles.
21. HumanLack of megalin expression in adult human terminal ileum suggests megalin-independent cubilin/amnionless activity during vitamin B12 absorption.
    Physiol Rep, 2014 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
    PMID 25052491DOI 10.14814/phy2.12086PMC4187553 (free full text)
    Verification: full text read; no PK numbers matched
    • Key findings · abstract:Cubilin plays an essential role in terminal ileum and renal proximal tubules during absorption of vitamin B12 and ligands from the glomerular ultrafiltrate.
    • Key findings · abstract:Patients with defects in either protein suffer from vitamin B12-malabsorption and in some cases proteinuria.
    • Key findings · abstract:To further investigate the potential role of amnionless and megalin in relation to cubilin function in terminal ileum and vitamin B12 uptake, we initiated a study of CUBN/cubilin, AMN/amnionless, and LRP2/megalin expression in adult human terminal ileum.
22. HumanHow can cobalamin injections be spaced in long-term therapy for inborn errors of vitamin B(12) absorption?
    Mol Genet Metab, 2012 · Design: not stated · n: 7 patients · abstract only (PubMed) · closed/paywalled
    PMID 22854512DOI 10.1016/j.ymgme.2012.07.007
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Inborn errors of cobalamin (Cbl, vitamin B(12)) absorption include hereditary intrinsic factor deficiency (HIFD) and Imerslund-Gräsbeck disease (IGD).
    • Key findings · abstract:In order to evaluate the optimal maintenance schedule of cobalamin injections, we retrospectively collected clinical, biological, molecular and treatment data on 7 patients affected with congenital Cbl malabsorption.
    • Key findings · abstract:These data suggest that patients affected with inborn errors of cobalamin absorption may be safely long-term treated with cobalamin injections every 6 months with careful follow-up of hematological and metabolic parameters.
23. HumanPharmacokinetics of oral cyanocobalamin formulated with sodium N-[8-(2-hydroxybenzoyl)amino]caprylate (SNAC): an open-label, randomized, single-dose, parallel-group study in healthy male subjects.
    Clin Ther, 2011 · Design: randomized · n: n = 4 · abstract only (PubMed) · closed/paywalled
    PMID 21722960DOI 10.1016/j.clinthera.2011.05.088
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:BACKGROUND: Vitamin B12 (cobalamin) deficiency may be caused by inadequate dietary intake of B12 or by conditions that result in malabsorption of the vitamin.
    • Key findings · abstract:OBJECTIVE: This study was conducted to compare the pharmacokinetics and tolerability of 2 oral formulations of cyanocobalamin-a marketed cyanocobalamin tablet (immediate-release B12 5 mg) and cyanocobalamin formulated with a proprietary carrier, sodium N-[8-(2-hydroxybenzoyl)amino]caprylate (SNAC)-to establish the feasibility of using an absorption enhancer with B12 to improve uptake of the vitamin.
    • Key findings · abstract:Human serum B12 was analyzed by ch[excerpt truncated in our database — see source]
    • Tmax · abstract:It also had a reduced T(max) compared with the commercial formulation (0.5 hours vs 6.83 hours, respectively).
    • Tmax · abstract:CONCLUSIONS: An oral formulation of 5-mg cyanocobalamin containing 100-mg SNAC, an absorption enhancer, provided significantly improved bioavailability and a significant decrease in T(max) for B12 in a small study of normal healthy subjects compared with a commercially available 5-mg cyanocobalamin oral formulation.
    • AUC · abstract:The oral cyanocobalamin formulation containing SNAC had greater mean absolute bioavailability than the commercial oral formulation (5.09% vs 2.16%, respectively), calculated on AUC(0-last) values uncorrected for baseline, weight, or body mass index.
24. HumanComparing the efficacy and tolerability of a new daily oral vitamin B12 formulation and intermittent intramuscular vitamin B12 in normalizing low cobalamin levels: a randomized, open-label, parallel-group study.
    Clin Ther, 2011 · Design: randomized · n: 22 patients · abstract only (PubMed) · closed/paywalled
    PMID 21600388DOI 10.1016/j.clinthera.2011.03.003
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Oral vitamin B(12) formulations have low bioavailability in patients with malabsorption and are considered less reliable than parenteral treatments.
    • Key findings · abstract:OBJECTIVE: The objective of this study was to compare the efficacy and safety profile of a new proprietary oral vitamin B(12) formulation (oral B(12)) with intramuscular (IM) vitamin B(12) (IM B(12)) in restoring normal serum B(12) concentrations in patients with low cobalamin levels (<350 pg/mL).
    • Key findings · abstract:The effect on holotranscobalamin II (active B(12)) levels was assessed as an exploratory end point and correlated to serum cobalamin levels in both[excerpt truncated in our database — see source]
25. HumanUptake of cobalamin and markers of cobalamin status: a longitudinal study of healthy pregnant women.
    Clin Chem Lab Med, 2011 · Design: not stated · abstract (PubMed); full-text PDF saved · open access (gold)
    PMID 21875397DOI 10.1515/CCLM.2011.682PDF
    Verification: full-text auto-extracted verbatim snippets with location; needs human check
    • Key findings · abstract:The absorption test CobaSorb was performed in all women implying measurement of holotranscobalamin or cyanocobalamin bound to transcobalamin before and after 2 days intake of 3 × 9 μg cobalamin.
    • Key findings · abstract:Serum cobalamin displayed a gradual decline during pregnancy (p<0.0001), while holotranscobalamin remained unchanged, despite an increase in total transcobalamin (p<0.0001).
    • Food effect · full text, p.2:three times; at pregnancy apoTC with cobalamin-coated beads (13). The total imprecision was weeks 13 (–1/q3), 24 ("1) and 36 ("1). At each visit, non-fasting 8% (13) and the intra-assay imprecision was 4% (14). ApoTC was EDTA blood and whole blood samples were collected from each calculated as totalTC minus holoTC. TotalHC was measured by an participant and used for analysis of markers of cobalami
    • Form comparison · full text, p.2:multivariate analyses, which is compa- increases more than 6 pmol/L and more than three-fold on day 3 rable to performing two-paired t-tests (week 13 vs. week 24 and compared to baseline (11). week 24 vs. week 36), which again is the same as testing week Fifty-two healthy Danish non-pregnant individuals that previous- 13sweek 24sweek 36. p-Values -0.05 were regarded as statis- ly underwent the Cob
    • Form comparison · full text, p.3:of HC for 27 pregnant out pregnancy (p-0.0001) resulting in mean increases of women analyzed at gestational week 13, -24 and -36. 55 pmol/L (week 13 compared to week 24) and 130 pmol/L (week 13 compared to week 36). HoloHC levels decreased during pregnancy (p-0.0001) and the changes were caused at two of the three (ns2) examinations. In six women, base- by a decline in Cbl-HC (p-0.0001), while ana
26. HumanVitamin B12 absorption judged by measurement of holotranscobalamin, active vitamin B12: evaluation of a commercially available EIA kit.
    Clin Chem Lab Med, 2011 · Design: not stated · n: n=25 · abstract only (PubMed) · closed/paywalled
    PMID 21995605DOI 10.1515/CCLM.2011.754
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:BACKGROUND: Active vitamin B12 absorption is followed by an increase in holotranscobalamin (holoTC) upon loading with a high physiological dose of the vitamin (the CobaSorb test).
    • Key findings · abstract:The EIA kit performed well in relation to the CobaSorb test and classified the patients studied as capable of absorbing vitamin B12 (n=10) or not (n=15), as did the in-house ELISA.
    • Key findings · abstract:CONCLUSIONS: The Active B12 (holoTC) EIA kit proved suitable for use with the CobaSorb test, but not for analysis of diluted serum samples.
27. HumanThe vitamin B12 absorption test, CobaSorb, identifies patients not requiring vitamin B12 injection therapy.
    Scand J Clin Lab Invest, 2011 · Design: clinical trial · n: 44 patients · abstract only (PubMed) · closed/paywalled
    PMID 21623649DOI 10.3109/00365513.2011.581389
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The capacity to absorb vitamin B12 was examined after a median of 13 months (range 5-32 months) by measurement of holotranscobalamin or cyanocobalamin on transcobalamin before and after 1 and 2 days intake of 3 × 9 μg of vitamin B12.
    • Key findings · abstract:Patients unable to absorb the vitamin continued treatment with vitamin B12 injection.
    • Key findings · abstract:RESULTS: Of the 44 patients studied, 35 patients were able to absorb vitamin B12.
    • Key findings · abstract:CONCLUSION: Our results suggest that the capacity for absorbing vitamin B12 should be examined prior to the choice of treatment.
28. HumanInborn errors of cobalamin absorption and metabolism.
    Am J Med Genet C Semin Med Genet, 2011 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 21312325DOI 10.1002/ajmg.c.30288
    Verification: abstract-only auto-extract; unverified
29. HumanAssessment of vitamin B(12) absorption based on the accumulation of orally administered cyanocobalamin on transcobalamin.
    Clin Chem, 2010 · Design: not stated · n: n = 31 · abstract only (PubMed) · open access (bronze)
    PMID 20040621DOI 10.1373/clinchem.2009.131524PMC10594690 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:BACKGROUND: Vitamin B(12), or cobalamin (Cbl), is absorbed in the intestine and transported to the cells bound to transcobalamin (TC).
    • Key findings · abstract:METHODS: TC was immunoprecipitated from serum samples obtained from healthy donors at baseline and at 24 h after oral administration of three 9-microg CNCbl doses over 1 day.
    • Key findings · abstract:We designed an absorption test based on measuring TC-CNCbl at baseline and 24 h after CNCbl intake and established a reference interval for the increase in TC-CNCbl (n = 78).
    • Key findings · abstract:The median absolute increase was 23 pmol/L (range, 6-64 pmol/L), and the relative increase was >3-fold.
    • Key findings · abstract:We[excerpt truncated in our database — see source]
    • Relative bioavailability · abstract:The median absolute increase was 23 pmol/L (range, 6-64 pmol/L), and the relative increase was >3-fold.
    • Fractional absorption · abstract:BACKGROUND: Vitamin B(12), or cobalamin (Cbl), is absorbed in the intestine and transported to the cells bound to transcobalamin (TC).
30. HumanChanges in blood pressure after administration of hydroxocobalamin: relationship to changes in plasma cobalamins-(III) concentrations in healthy volunteers.
    Clin Toxicol (Phila), 2008 · Design: randomized · n: n = 41 · abstract only (PubMed) · closed/paywalled
    PMID 18584369DOI 10.1080/15563650701829763
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Change in mean arterial pressure (MAP) was strongly correlated with plasma area-under-the-concentration-time curves (AUCs) of total and free cobalamins-(III) during infusion (r > 0.7) but not through 24 hours post-infusion (r < or = 0.36).
    • AUC · abstract:Change in mean arterial pressure (MAP) was strongly correlated with plasma area-under-the-concentration-time curves (AUCs) of total and free cobalamins-(III) during infusion (r > 0.7) but not through 24 hours post-infusion (r < or = 0.36).
31. HumanNonradioactive vitamin B12 absorption test evaluated in controls and in patients with inherited malabsorption of vitamin B12.
    Clin Chem, 2005 · Design: not stated · n: 17 patients · abstract only (PubMed) · open access (green)
    PMID 16166166DOI 10.1373/clinchem.2005.055509
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:BACKGROUND: Current tests for evaluation of vitamin B(12) absorption are problematic because they involve the use of radioactively labeled vitamin B(12).
    • Key findings · abstract:We describe a vitamin B(12) absorption test that circumvents this problem.
    • Key findings · abstract:We studied 17 patients with inherited malabsorption of vitamin B(12) attributable to Imerslund-Grasbeck syndrome (n = 13) or intrinsic factor deficiency (n = 4), their obligate heterozygous biological parents (n = 19), and healthy controls (n = 44).
    • Key findings · abstract:RESULTS: In the patients, the median (range) change of holo-TC after the B(12) load was not significant [1 (-42 to[excerpt truncated in our database — see source]
32. HumanSerum folate and Vitamin B12 levels in women using modern oral contraceptives (OC) containing 20 microg ethinyl estradiol.
    Eur J Obstet Gynecol Reprod Biol, 2003 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 12593896DOI 10.1016/s0301-2115(02)00371-8
    Verification: abstract-only auto-extract; unverified
33. HumanEfficacy of methylcobalamin on lowering total homocysteine plasma concentrations in haemodialysis patients receiving high-dose folic acid supplementation.
    Nephrol Dial Transplant, 2002 · Design: randomized · n: n=7 · abstract only (PubMed) · not checked (off-topic)
    PMID 11981084DOI 10.1093/ndt/17.5.916
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:METHODS: In order to assess the efficacy on lowering plasma tHcy levels (fasting concentration), 21 HD patients, were randomly assigned and provided folic acid supplementation: 15 mg/day orally (group I, n=7); methylcobalamin 500 mg intravenously after each HD, in addition to folic acid (group II, n=7); or vitamin B(6) (B(6)), 60 mg/day orally, in addition to folic acid and methylcobalamin (group III, n=7).
    • Key findings · abstract:The following measurements were also made before and after supplementation for each group: serum folic acid, B(6), and vitamin B(12) (B(12)) concentrations (including measurement of propo[excerpt truncated in our database — see source]
    • Food effect · abstract:METHODS: In order to assess the efficacy on lowering plasma tHcy levels (fasting concentration), 21 HD patients, were randomly assigned and provided folic acid supplementation: 15 mg/day orally (group I, n=7); methylcobalamin 500 mg intravenously after each HD, in addition to folic acid (group II, n=7); or vitamin B(6) (B(6)), 60 mg/day orally, in addition to folic acid and methylcobalamin (group III, n=7).
    • Food effect · abstract:Mean percentage reduction in fasting tHcy was 17.3+/-8.4% in group I, 57.4+/-13.3% in group II, 59.9+/-5.6% in group III, and 18.7+/-7.5% in HD controls.
    • Food effect · abstract:Treatment resulted in normaliza
34. HumanVitamin B12 and folate bioavailability from two prenatal multivitamin/multimineral supplements.
    Am J Perinatol, 2000 · Design: crossover · abstract only (PubMed) · closed/paywalled
    PMID 11041441DOI 10.1055/s-2000-9420
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:In this crossover, single-blind study, the bioavailability of B12 and folate, fasting and postprandially, was measured in 30 pregnant women for two prenatal multivitamin/multimineral supplements (Stuartnatal Plus and Materna, Wyeth-Ayerst Pharmaceuticals, Philadelphia, PA) and a placebo.
    • Key findings · abstract:Blood samples were obtained before supplementation and at 1, 3, 6, and 8 hr after supplementation serum levels of the two vitamins were measured by radioimmunoassay.
    • Key findings · abstract:The absorption peak of both vitamins occurred at 3 hours after ingestion of a supplement.
    • Key findings · abstract:There was 30% greater B12 absorption for Stuartna[excerpt truncated in our database — see source]
    • Fractional absorption · abstract:Both vitamins were readily absorbed (within 3 hours) into the maternal hepatic portal circulation.
    • Food effect · abstract:In this crossover, single-blind study, the bioavailability of B12 and folate, fasting and postprandially, was measured in 30 pregnant women for two prenatal multivitamin/multimineral supplements (Stuartnatal Plus and Materna, Wyeth-Ayerst Pharmaceuticals, Philadelphia, PA) and a placebo.
    • Food effect · abstract:Similarly, there was 117% greater folate absorption fasting for Stuartnatal Plus (163 +/- 15 vs. 75 +/- 15 nmol, p < or = 0.001) and 57% greater absorption for Materna (207 +/- 21 vs. 132 +/- 13 nmol, p < or = 0.01).
35. HumanIncreased intake of calcium reverses vitamin B12 malabsorption induced by metformin.
    Diabetes Care, 2000 · Design: clinical trial · n: 21 patients · abstract only (PubMed) · closed/paywalled
    PMID 10977010DOI 10.2337/diacare.23.9.1227
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:OBJECTIVE: Of patients who are prescribed metformin, 10-30% have evidence of reduced vitamin B12 absorption.
    • Key findings · abstract:B12-intrinsic factor complex uptake by ileal cell surface receptors is known to be a process dependent on calcium availability Metformin affects calcium-dependent membrane action.
    • Key findings · abstract:The objective of this study was to determine the magnitude and mechanism of the reduction in serum vitamin B12 after metformin administration.
    • Key findings · abstract:Monthly serum total vitamin B12 measurements and holotranscobalamin (holoTCII) (B12-TCII) were performed.
    • Key findings · abstract:RESULTS: Serial serum vitamin B12 determinations revea[excerpt truncated in our database — see source]
36. HumanCyanocobalamin absorption abnormality in alcoholics is improved by oral supplementation with a fermented papaya-derived antioxidant.
    Hepatogastroenterology, 2000 · Design: not stated · abstract only (PubMed) · unknown
    PMID 11020912
    Verification: abstract-only auto-extract; unverified
37. HumanGastric intrinsic factor production and vitamin B12 absorption after oesophageal resection using stomach as substitute.
    Eur J Cardiothorac Surg, 1999 · Design: stable-isotope · abstract only (PubMed) · open access (bronze)
    PMID 10554842DOI 10.1016/s1010-7940(99)00214-6
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:OBJECTIVE: To investigate whether the use of the stomach as a substitute after oesophageal resections causes disturbances in vitamin B12 absorption due to deficient intrinsic factor (IF) production.
    • Key findings · abstract:RESULTS: In two patients the test showed abnormally low absorption of vitamin B12.
    • Key findings · abstract:However, no patient showed deficient intrinsic factor production with absorption ratios between vitamin B12 +/- IF of 0.87-1.14 (reference interval: 0.70-1.20).
    • Key findings · abstract:However, vitamin B12 absorption may be low due to other factors, and should be looked for in all patients surviving more than a couple of months postop[excerpt truncated in our database — see source]
38. HumanDiscovery of vitamin B12 in the liver and its absorption factor in the stomach: a historical review.
    J Gastroenterol Hepatol, 1999 · Design: not stated · abstract only (PubMed) · unknown
    PMID 10207776
    Verification: abstract-only auto-extract; unverified
39. HumanBioavailability of dried asakusanori (porphyra tenera) as a source of Cobalamin (Vitamin B12).
    Int J Vitam Nutr Res, 1999 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 10642899DOI 10.1024/0300-9831.69.6.412
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The urinary methylmalonic acid excretion increased when human female volunteers were given 40 g of dried nori daily during the test period.
    • Key findings · abstract:On the other hand, the urinary methylmalonic acid excretion did not change when volunteers were daily given 320 g of raw nori, which was equivalent to 40 g of the dried one on the basis of dehydrated weight, during the test period.
40. HumanNasal absorption of hydroxocobalamin in healthy elderly adults.
    Br J Clin Pharmacol, 1998 · Design: randomized; crossover; stable-isotope · abstract only (PubMed) · open access (green)
    PMID 9489599DOI 10.1046/j.1365-2125.1998.00642.xPMC1873990 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:AIMS: To investigate the nasal absorption of hydroxocobalamin in 10 healthy elderly adults.
    • Key findings · abstract:RESULTS: The maximal plasma cobalamin concentration (Cmax) after nasal administration of 750 microg hydroxocobalamin was 1900 +/- 900 pmol l(-1) (mean +/- s.d.).
    • Key findings · abstract:The maximal plasma cobalamin concentration was reached in 35 +/- 13 min (t[max]).
    • Key findings · abstract:The Cmax after nasal administration of 1500 microg hydroxocobalamin was 3500 +/- 2500 pmol l(-1) with a t(max) of 28 +/- 16 min.
    • Key findings · abstract:Both the AUC(0,240 min) and AUC(0,00) increased significantly with an increase of the dose from 750 microg to 1500 microg (P =[excerpt truncated in our database — see source]
    • Cmax · abstract:RESULTS: The maximal plasma cobalamin concentration (Cmax) after nasal administration of 750 microg hydroxocobalamin was 1900 +/- 900 pmol l(-1) (mean +/- s.d.).
    • Cmax · abstract:The Cmax after nasal administration of 1500 microg hydroxocobalamin was 3500 +/- 2500 pmol l(-1) with a t(max) of 28 +/- 16 min.
    • Tmax · abstract:The Cmax after nasal administration of 1500 microg hydroxocobalamin was 3500 +/- 2500 pmol l(-1) with a t(max) of 28 +/- 16 min.
    • AUC · abstract:Both the AUC(0,240 min) and AUC(0,00) increased significantly with an increase of the dose from 750 microg to 1500 microg (P = 0.037 and P = 0.028, respectively).
41. HumanEffects of aldose reductase inhibitor and vitamin B12 on myocardial uptake of iodine-123 metaiodobenzylguanidine in patients with non-insulin-dependent diabetes mellitus.
    Eur J Nucl Med, 1998 · Design: not stated · n: 20 healthy volunteers · abstract only (PubMed) · closed/paywalled
    PMID 9871096DOI 10.1007/s002590050343
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:This study was undertaken to examine the effects of aldose reductase inhibitor (ARI) and vitamin B12 (VB12) on myocardial uptake of iodine-123 metaiodobenzylguanidine (MIBG) in patients with diabetic autonomic disorder.
    • Food effect · abstract:Seventeen of these 34 patients received 150 mg/day of doses before meals, and the other 17 received 1.5 mg/day of mecobalamin (VB12 group) in three divided doses after meals, for 3-5 months.
42. HumanLow serum vitamin B12 levels in chronic high-flux haemodialysis patients.
    Nephron, 1997 · Design: stable-isotope · n: 22 patients · abstract only (PubMed) · not checked (off-topic)
    PMID 9069445DOI 10.1159/000189546
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:We measured serial predialysis serum B12 levels, at 3- to 6-month intervals, in 67 unselected patients on our high-flux haemodialysis programme.
    • Key findings · abstract:Over a 12-month period, there was a significant fall in serum B12 from 497 +/- 200 (SD) to 391 +/- 131 ng/l (p < 0.001). 22 patients developed subnormal serum B12 levels and were commenced on hydroxocobalamin supplements.
    • Key findings · abstract:Absorption studies by whole-body counting on 6 patients using 57Co and 58Co showed normal B12 absorption.
    • Key findings · abstract:This study demonstrates that low serum B12 levels occur in high-flux haemodialysis patients and that losses during dialys[excerpt truncated in our database — see source]
43. HumanNormalization of plasma vitamin B12 concentration by intranasal hydroxocobalamin in vitamin B12-deficient patients.
    Gastroenterology, 1997 · Design: clinical trial · n: 6 patients · abstract (PubMed); full-text PDF saved · open access (green)
    PMID 9247460DOI 10.1053/gast.1997.v113.pm9247460PDF
    Verification: full-text auto-extracted verbatim snippets with location; needs human check
    • Key findings · abstract:METHODS: Six patients with plasma cobalamin concentrations of < 200 ng/L were recruited.
    • Key findings · abstract:Plasma cobalamin concentrations were determined 1 hour after hydroxocobalamin application and on days 0, 7, 21, 28, and 35.
    • Key findings · abstract:In these 6 patients, there was an eightfold increase of mean baseline cobalamin concentrations.
    • Form comparison · full text, p.3:hip has been established between the molecular weight of a drug and the propor- tion of the intranasal dose absorbed.4 A log-plot of nasal absorption vs. molecular weight shows good bioavailabil- Figure 1. Increase of plasma cobalamin concentration 1 hour after ity for all compounds up to a molecular weight of about 1500 mg of intranasal hydroxocobalamin on days 0, 14, and 21 in 6 patients. j, Bef
44. HumanFree and protein-bound cobalamin absorption in healthy middle-aged and older subjects.
    J Am Geriatr Soc, 1996 · Design: not stated · n: 13 subjects · abstract only (PubMed) · open access (green)
    PMID 8708306DOI 10.1111/j.1532-5415.1996.tb01866.x
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:MEASUREMENTS: Protein-bound cobalamin absorption was assessed by 48-hour urinary excretion method following oral administration of scrambled egg yolk, labeled in vivo with 57 Co-cobalamin by injecting a hen with 57 Co-cyanocobalamin.
    • Key findings · abstract:Free cobalamin absorption was assessed by 48-hour urinary excretion method following oral administration of crystalline 57 Co-cyanocobalamin.
    • Key findings · abstract:RESULTS: The median urinary excretion of egg yolk 57 Co-cobalamin in middle-aged subjects was 12.3% (25th and 75th percentiles 10.5%-14.5%) compared with 11.7% (25th and 75th percentiles 9.8%-13.6%) in older subjects (P[excerpt truncated in our database — see source]
45. HumanEffect of short- and long-term treatment with omeprazole on the absorption and serum levels of cobalamin.
    Aliment Pharmacol Ther, 1996 · Design: clinical trial · n: 25 patients · abstract only (PubMed) · closed/paywalled
    PMID 8853757DOI 10.1046/j.1365-2036.1996.27169000.x
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:METHODS: In eight former duodenal ulcer patients absorption of unbound and protein-bound cobalamin was determined by measuring 24-h urinary excretion of unbound 58Co-cyancobalamin or protein-bound 57Co-cyanocobalamin during a modified Schilling test.
    • Key findings · abstract:Serum cobalamin levels were assessed in 25 patients with gastro-oesophageal reflux disease (GERD) before and during long-term maintenance therapy with omeprazole.
    • Key findings · abstract:Excretion of 57Co-cyanocobalamin, however, decreased significantly during treatment with both 20 mg omeprazole (mean +/- S.E.M.: 1.31 +/- 0.20 vs. 0.54 +/- 0.17%;[excerpt truncated in our database — see source]
    • Key findings · abstract:Mean serum cobala[excerpt truncated in our database — see source]
46. HumanInfluence of continent ileal urinary diversion on vitamin B12 absorption.
    J Urol, 1996 · Design: not stated · n: 25 patients · abstract only (PubMed) · unknown
    PMID 8632531
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:PURPOSE: Because vitamin B12 is mainly absorbed in the terminal ileum, we evaluated potential absorption deficiencies in continent ileal reservoirs.
    • Key findings · abstract:A Schilling test and red blood count were done, and serum levels of vitamin B12 and folic acid were determined.
    • Key findings · abstract:RESULTS: Absorptive capacity was decreased in 20 of the 25 Kock pouch patients but none of the 29 ileal neobladder patients.
    • Key findings · abstract:CONCLUSIONS: A loss of 50 cm. of terminal ileum seems to be the critical margin sufficient vitamin B12 absorption.
    • Fractional absorption · abstract:PURPOSE: Because vitamin B12 is mainly absorbed in the terminal ileum, we evaluated potential absorption deficiencies in continent ileal reservoirs.
47. HumanCobalamin forms and analogues in plasma and myeloid cells during chronic myelogenous leukaemia related to clinical condition.
    Br J Haematol, 1995 · Design: stable-isotope · abstract only (PubMed) · closed/paywalled
    PMID 7772517DOI 10.1111/j.1365-2141.1995.tb08419.x
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Buffy coat cells and splenic tissue had a higher proportion of 5'-deoxyadenosylcobalamin and a lower proportion of methylcobalamin than plasma; still, there was relatively more methylcobalamin than in normal tissue.
48. HumanEffects of vitamin B12, folate, and vitamin B6 supplements in elderly people with normal serum vitamin concentrations.
    Lancet, 1995 · Design: randomized; double-blind · abstract only (PubMed) · open access (hybrid)
    PMID 7603218DOI 10.1016/s0140-6736(95)92113-3
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:In a prospective, multicentre, double-blind controlled study, the effect of an intramuscular vitamin supplement containing 1 mg vitamin B12, 1.1 mg folate, and 5 mg vitamin B6 on serum concentrations of methylmalonic acid (MMA), homocysteine (HCYS), 2-methylcitric acid (2-MCA), and cystathionine (CYSTA) was compared with that of placebo in 175 elderly subjects living at home and 110 in hospital.
    • Key findings · abstract:Initially elevated metabolite concentrations returned to normal in a higher proportion of the vitamin than of the placebo group: 92% vs 20% for HYCS; 82% vs 20% for MMA; 62% vs 25% for 2-MCA; and 42%
49. HumanMalabsorption and deficiency of vitamin B12 in HIV-infected patients with chronic diarrhea.
    Dig Dis Sci, 1994 · Design: not stated · n: 16 patients · abstract only (PubMed) · closed/paywalled
    PMID 7924736DOI 10.1007/BF02090365
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:These 16 patients had both a stage II Schilling test and measurement of multiple serum D-xylose concentrations performed after both oral and intravenous doses of D-xylose.
    • Key findings · abstract:D-Xylose bioavailability correlated closely with vitamin B12 absorption (r = 0.648, P < 0.01).
    • Key findings · abstract:Comparisons of mean values for CD4 count, serum albumin, Karnovsky score, six-month weight loss, 1-hr serum D-xylose levels and MCV failed to reveal a significant difference between those with and without abnormal serum vitamin B12 levels.
    • Key findings · abstract:Malabsorption of vitamin B12 occurs in the setting of an enteropathic process effecting[excerpt truncated in our database — see source]
50. HumanEffect of hypochlorhydria due to omeprazole treatment or atrophic gastritis on protein-bound vitamin B12 absorption.
    J Am Coll Nutr, 1994 · Design: randomized · n: n = 8 · abstract only (PubMed) · closed/paywalled
    PMID 7706591DOI 10.1080/07315724.1994.10718452
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:OBJECTIVE: To investigate the effects of hypochlorhydria and acidic drink ingestion on protein-bound vitamin B12 absorption in elderly subjects.
    • Key findings · abstract:METHODS: Absorption of protein-bound vitamin B12 was examined in elderly normal subjects (n = 8), and in hypochlorhydric subjects due to omeprazole treatment (n = 8) or with atrophic gastritis (n = 3).
    • Key findings · abstract:Subjects underwent absorption tests of protein-bound vitamin B12 ingested with water, cranberry juice and 0.1 N hydrochloric acid.
    • Key findings · abstract:RESULTS: Protein-bound vitamin B12 absorption was lower in the omeprazole-treated group (0.50%) compared to the norm[excerpt truncated in our database — see source]
    • Fractional absorption · abstract:With cranberry juice ingestion, the omeprazole-treated group showed an increase in absorbed protein-bound vitamin B12 (p = 0.025).
51. HumanOmeprazole therapy causes malabsorption of cyanocobalamin (vitamin B12).
    Ann Intern Med, 1994 · Design: randomized · abstract only (PubMed) · closed/paywalled
    PMID 8273984DOI 10.7326/0003-4819-120-3-199402010-00006
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:OBJECTIVE: To evaluate protein-bound cyanocobalamin (vitamin B12) absorption before and after omeprazole (Prilosec) therapy in healthy male volunteers.
    • Key findings · abstract:INTERVENTION: Each participant had a modified Schilling test (protein-bound cyanocobalamin) and a gastric analysis, as well as measurements of serum vitamin B12, gastrin, and folate levels.
    • Key findings · abstract:RESULTS: At the end of the 2-week treatment period, cyanocobalamin absorption decreased from 3.2% to 0.9% (P = 0.031) in participants receiving 20 mg of omeprazole daily.
    • Key findings · abstract:In patients taking 40 mg of omeprazole daily, cyanocobalamin absorption decreased[excerpt truncated in our database — see source]
52. HumanHydroxocobalamin as a cyanide antidote: safety, efficacy and pharmacokinetics in heavily smoking normal volunteers.
    J Toxicol Clin Toxicol, 1993 · Design: not stated · abstract only (PubMed) · not checked (off-topic)
    PMID 8492341DOI 10.3109/15563659309000395
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Hydroxocobalamin alone decreased whole blood cyanide levels by 59% and increased urinary cyanide excretion.
    • Key findings · abstract:Vd (beta), 0.24 L/kg; and mean peak serum concentration 753 mcg/mL (560 mumol/L) at 0-50 minutes after completion of infusion.
    • Cmax · abstract:Vd (beta), 0.24 L/kg; and mean peak serum concentration 753 mcg/mL (560 mumol/L) at 0-50 minutes after completion of infusion.
53. HumanEffect of histamine H2-receptor antagonists on vitamin B12 absorption.
    Ann Pharmacother, 1992 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 1358279DOI 10.1177/106002809202601018
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:OBJECTIVE: To discuss the potential of histamine H2-receptor antagonists (H2RAs) to cause malabsorption of vitamin B12 (cyanocobalamin).
    • Key findings · abstract:STUDY SELECTION: Studies evaluating the effect of H2RAs on vitamin B12 absorption were reviewed.
    • Key findings · abstract:Intrinsic factor (IF), also produced by gastric parietal cells, is required for vitamin B12 absorption from the gastrointestinal tract.
    • Key findings · abstract:Although H2RAs have not conclusively been shown to decrease IF secretion, studies have demonstrated a significant reduction in food-bound vitamin B12 absorption secondary to decreased acid secretion in patients taking these[excerpt truncated in our database — see source]
54. HumanBound vitamin B12 absorption in patients with low serum B12 levels.
    Am J Hematol, 1992 · Design: not stated · n: 94 patients · abstract only (PubMed) · closed/paywalled
    PMID 1609768DOI 10.1002/ajh.2830400302
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:In many patients with low serum levels of vitamin B12, the absorption of the free vitamin has been normal.
    • Key findings · abstract:The present study, using a total body counter 57CoB12 absorption method that clearly separated those with intrinsic factor deficiency from controls, found that of 94 patients with low B12 levels and intact stomachs in whom the absorption of free and bound B12 was determined, 44 (47%) had normal absorption of both.
    • Key findings · abstract:However, 20 of the 94 (21%) with normal absorption of free B12 had low absorption of bound B12.
    • Key findings · abstract:The remainder (32%) had low absorption of both free and bound B12.
    • Key findings · abstract:All pa[excerpt truncated in our database — see source]
55. HumanNormalization of vitamin B12 absorption after ileal resection in children.
    J Paediatr Child Health, 1992 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 1562369DOI 10.1111/j.1440-1754.1992.tb02635.x
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Impaired Vitamin B12 absorption after significant ileal resection has been reported to be permanent, although partial recovery after ileal bypass can occur.
    • Key findings · abstract:Three children are presented in whom Vitamin B12 malabsorption returned to normal 6-8 years after ileal resection.
56. HumanThe ileum is the major site of absorption of vitamin B12 analogues.
    Am J Gastroenterol, 1989 · Design: not stated · n: 93 patients · abstract only (PubMed) · unknown
    PMID 2912026
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Non-cobalamin vitamin B12 analogues constitute a significant percentage of total corrinoids in human serum.
    • Key findings · abstract:We studied the sites of production and absorption of B12 analogues by measuring serum vitamin B12 and analogues in 93 patients with various gastrointestinal diseases: pernicious anemia (PA), ileal resections, ileitis, Crohn's colitis, ulcerative colitis, and irritable bowel syndrome (IBS).
    • Key findings · abstract:These data suggest that serum B12 analogues are absorbed in the ileum by a mechanism independent of intrinsic factor, and that colonic bacteria and endogenous metabolism of vitamin B12 do not contr[excerpt truncated in our database — see source]
    • Fractional absorption · abstract:These data suggest that serum B12 analogues are absorbed in the ileum by a mechanism independent of intrinsic factor, and that colonic bacteria and endogenous metabolism of vitamin B12 do not contribute significantly to their level.
57. HumanVitamin B12 absorption after allogeneic bone marrow transplantation.
    J Clin Pathol, 1987 · Design: not stated · n: 26 patients · abstract only (PubMed) · open access (bronze)
    PMID 3323253DOI 10.1136/jcp.40.12.1472PMC1141286 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The B12 absorption test (Schilling test) with intrinsic factor was used to examine ileal B12 absorption in 26 patients after allogeneic transplantation.
    • Key findings · abstract:The test was well tolerated and showed a profound fall in B12 absorption, which was maximal at two weeks after transplantation and recovered by eight weeks.
    • Key findings · abstract:When compared with nine patients without GVHD there was a significant (p less than 0.005) reduction of B12 absorption.
    • Key findings · abstract:These findings suggest that the B12 absorption test may be a useful non-invasive method of studying bowel function after bone marrow transplantation.
58. HumanVitamin B12 absorption capacity in healthy children.
    J Pediatr Gastroenterol Nutr, 1986 · Design: stable-isotope · n: 47 healthy children · abstract only (PubMed) · unknown
    PMID 3958854
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:B12 absorption was investigated in 47 healthy children aged 7 months to 15.8 years (median 4.9 years).
    • Key findings · abstract:The B12 absorption was measured by a double-isotope technique using 57CoB12 and 51CrCl3, the latter being the inabsorbable marker.
    • Key findings · abstract:The results were presented as fractional absorption of B12 (FAB12).
    • Key findings · abstract:Within the different age groups, the absorption test was performed by means of the following oral amounts of B12: 0- less than 1 year, 0.5 microgram; 1-3 years: 1.7 micrograms, 4-6 years, 2.5 micrograms; 7-10 years; 3.3 micrograms; and 11-15 years, 4.5 micrograms.
    • Key findings · abstract:These results may be inte[excerpt truncated in our database — see source]
    • Fractional absorption · abstract:The results were presented as fractional absorption of B12 (FAB12).
    • Fractional absorption · abstract:When a high oral amount of B12 was given (i.e., three times the saturation dose), the FAB12 ranged from 0 to 20% (median 9%), whereas a low amount (i.e., one-ninth of the saturation dose) produced fractional absorptions from 65 to 82% (median 74%).(ABSTRACT TRUNCATED AT 250 WORDS)
59. HumanDisorders of cobalamin (vitamin B12) absorption and transport.
    Annu Rev Med, 1985 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 3994330DOI 10.1146/annurev.me.36.020185.000521
    Verification: abstract-only auto-extract; unverified
60. HumanVitamin B12 absorption in cystic fibrosis.
    Acta Paediatr Scand, 1984 · Design: not stated · n: 30 patients · abstract only (PubMed) · closed/paywalled
    PMID 6464742DOI 10.1111/j.1651-2227.1984.tb09967.x
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Vitamin B12 absorption was measured in 30 patients with cystic fibrosis by means of the urinary excretion method and found to be impaired, i.e. less than 10%, in 25.
    • Key findings · abstract:The mean urinary excretion amounted to 4.7 +/- 0.8%.
    • Key findings · abstract:In all patients vitamin B12 absorption improved by the addition of trypsin (18.9 +/- 2.1%).
    • Key findings · abstract:Addition of the vitamin B12 analogue cobinamide, which prevents vitamin B12-binding by R-binders, raised the vitamin B12 absorption to 15.0 +/- 2.2%.
    • Key findings · abstract:Assuming that cobinamide addition was effective in suppressing all R-binder activity, the additional effect of trypsin suggests a s[excerpt truncated in our database — see source]
61. HumanVitamin B12 absorption after necrotizing enterocolitis.
    Arch Dis Child, 1984 · Design: not stated · abstract only (PubMed) · open access (bronze)
    PMID 6476869DOI 10.1136/adc.59.8.731PMC1628616 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:They may therefore be at risk of vitamin B12 malabsorption, and later of vitamin B12 deficiency.
    • Key findings · abstract:A method of measuring B12 absorption is described and the results are given.
62. HumanInfluence of dietary fiber (konjac mannan) on absorption of vitamin B12 and vitamin E.
    Tohoku J Exp Med, 1983 · Design: not stated · abstract (PubMed); full-text PDF saved · open access (bronze)
    PMID 6096987DOI 10.1620/tjem.141.suppl_677PDF
    Verification: full-text auto-extracted verbatim snippets with location; needs human check
    • Key findings · abstract:The absorption rate of vitamin E into the intestine was reduced when konjac mannan was added to the test meals, but that of vitamin B12 was not reduced in normal or diabetic subjects.
    • Food effect · abstract:On the first day of the study, subjects were given a control test meal, prepared by adding vitamin B12 3000r (mecobalamin) and vitamin E 500 mg (tocopherol acetate), after a 12-hr overnight fast.
    • Food effect · abstract:Then, on the second day in the case of the normal subjects, and on the seventh day in the case of the diabetic subjects, the subjects received a second test meal with 3.9 g konjac mannan (glucomannan).
    • Food effect · abstract:Venous blood samples were taken immediately before the test meal and again after 1, 3, 5, 8, 12 and 24 hr for analysis of vitamins.
    • Food effect · abstract:The absorption rate of vitamin E into the intestine was reduced
    • Form comparison · full text, p.4:and, when konjac mannan was added to the test meals, the serum levels of vitamin E in normal subjects were significantly reduced at 1 hr (17. 8•}8.7% vs. -4.3•}2.7% ; p <0.0125), 3 hr (15.6•}4.8% vs. -0.1•}4.7% ; p <0. 025), 8 hr (47.1•}11.5% vs. 17.8•}4.8% ; p <0.0125) and 12 hr (49.8•}14.2% vs. 20.4•}8.2% ; p <0.05) respectively (Fig. 3). The peak serum vitamin E levels were reduced in all diabe
63. HumanVitamin B12 malabsorption after jejuno-ileal bypass surgery.
    Acta Med Acad Sci Hung, 1982 · Design: not stated · abstract only (PubMed) · unknown
    PMID 7180363
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Six patients subjected to jejuno-ileal bypass surgery for obesity were studied for vitamin B12 absorption by the use of the Schilling test, together with measurement of the serum B12 level preoperatively and at 2, 6, 12, 18 and 24 months after the operation.
    • Key findings · abstract:During the follow-up period of 2 years, the serum vitamin B12 level gradually declined to abnormally low values.
    • Key findings · abstract:A postoperative fall of the originally normal vitamin B12 absorption to abnormal values was found.
    • Key findings · abstract:Oral administration of tetracycline resulted in a transitory improvement of the results by the Schilling test, but after it[excerpt truncated in our database — see source]
64. HumanEffect of folate deficiency on vitamin B12 absorption.
    Ann Nutr Metab, 1982 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 7149639DOI 10.1159/000176587
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:In three different groups of patients presenting severe folate deficiency (purely nutritional folate deficiency, chronic alcoholism or various intestinal diseases), vitamin B12 absorption has been tested by Schilling test in order to investigate the possible effect of folate deficiency on B12 absorption.
    • Key findings · abstract:Following this study, it appears that folate deficiency in itself, even severe, cannot induce vitamin B12 malabsorption, since in the first group, consisting of malnourished old people, the Schilling test was always normal even in those who presented a lowered B12 serum level; in the group o[excerpt truncated in our database — see source]
65. HumanVitamin B12 absorption and exocrine pancreatic insufficiency in childhood.
    Eur J Pediatr, 1981 · Design: not stated · n: 19 patients · abstract only (PubMed) · closed/paywalled
    PMID 7215391DOI 10.1007/BF00441715
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The absorption of vitamin B12, labelled with radioactive 58Co, was measured in 19 patients with cystic fibrosis and one child with the Shwachman-Diamond syndrome using the whole body counting technique.
    • Key findings · abstract:We found vitamin B12 absorption reduced to 7.97 on average, compared to 59.2% for the control group.
    • Key findings · abstract:The low vitamin B12 absorption correlated well with the reduced fat retention coefficients.
    • Key findings · abstract:After adding 0.212 pancreatin to the radioactive vitamin B12 test dose, the absorption quotas improved in all cases, the average being 61%.
    • Key findings · abstract:A meal poor in vitamin B12 tended to increase the absorp[excerpt truncated in our database — see source]
    • Food effect · abstract:A meal poor in vitamin B12 tended to increase the absorption of the radioactive test dose to 23% on average.
66. HumanIntrinsic factor mediated cobalamin absorption.
    Ann Clin Lab Sci, 1980 · Design: not stated · abstract only (PubMed) · unknown
    PMID 7004331
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The physiological absorption of vitamin B12 is a complex process which requires the interaction of several macromolecules.
    • Key findings · abstract:As a measure of this overall process, the vitamin B12 absorption test has helped to identify abnormal vitamin B12 absorption in patients with exocrine pancreatic insufficiency and familial vitamin B12 malabsorption (Immerslung-Grasbeck syndrome).
    • Key findings · abstract:Progress into understanding the role of proteolytic enzymes in promoting vitamin B12 absorption as well as the molecular events of vitamin B12 transport across the ileal cell has been brought about by recent investigation base[excerpt truncated in our database — see source]
67. Human[Symptom changes and rational therapy of vitamin B12 absorption disturbances (author's transl)].
    MMW Munch Med Wochenschr, 1977 · Design: not stated · abstract only (PubMed) · unknown
    PMID 409935
    Verification: abstract-only auto-extract; unverified
68. HumanThe relation between ileal resection and vitamin B12 absorption.
    Can J Surg, 1977 · Design: not stated · n: 33 patients · abstract only (PubMed) · unknown
    PMID 890622
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Over 15 years, 33 patients, who had had 36 ileal resections that included the terminal ileum, had Schilling tests to measure the absorption of vitamin B12.
    • Key findings · abstract:Retention of terminal ileum tends to preserve vitamin B12 absorption capacity.
    • Key findings · abstract:Thus, if more than 60 cm of terminal ileum is removed, fat and B12 malabsorption are likely.
69. HumanBile acid metabolism and vitamin B12 absorption in ulcerative colitis.
    Scand J Gastroenterol, 1976 · Design: stable-isotope · n: 10 patients · abstract only (PubMed) · unknown
    PMID 1006150
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Bile acid and vitamin B12 malabsorption were evaluated in 34 cases of ulcerative colitis.
    • Key findings · abstract:Bile acid absorption was assessed by the cholyl-glycine-1-14C breath test combined with faecal analysis.
    • Key findings · abstract:The 14C-excretion in breath was abnormally elevated in only one of the patients in the total material.
    • Key findings · abstract:Patients colectomized for ulcerative colitis had an extremely high excretion of isotope in the ileal effluent, from 15 to 81 per cent of the dose given.
    • Key findings · abstract:Vitamin B12 malabsorption was only present in five patients.
    • Food effect · abstract:The postprandial duodenal bile acid concentration was abnormally low in 13 of 24 non-operated cases and found to be correlated to the activity of the disease.
70. HumanInhibitory effect of eggs on vitamin B12 absorption: description of a simple ovalbumin 57Co-vitamin B12 absorption test.
    Br J Haematol, 1976 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 944587DOI 10.1111/j.1365-2141.1976.tb03537.x
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Ovalbumin, and to a lesser degree, egg yolks were observed to inhibit vitamin B12 absorption.
71. HumanComparison of the bioavailability of cyanocobalamin from capsule and liquid dosage forms.
    Am J Hosp Pharm, 1975 · Design: not stated · abstract only (PubMed) · unknown
    PMID 1190217
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Excretion, a measure of absorption, was between 2 percent and 66 percent greater with the liquid form.
72. HumanVitamin B12 absorption from eggs.
    Proc Soc Exp Biol Med, 1975 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 1172618DOI 10.3181/00379727-149-38940
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Judged by the urinary excretion test and the plasma absorption of radioactivity the average absorption from boiled and fried eggs was more than twice that from scrambled whole eggs, but less than half that absorbed from crystalline 57Co B12.
    • Fractional absorption · abstract:Judged by the urinary excretion test and the plasma absorption of radioactivity the average absorption from boiled and fried eggs was more than twice that from scrambled whole eggs, but less than half that absorbed from crystalline 57Co B12.
73. HumanIntestinal iron absorption under the influence of available storage iron and erythroblastic hyperplasia. Comparative studies in children with hereditary spherocytosis, nonspherocytic enzymopenic hemolytic anemia, acquired hemolytic anemia, vitamin B12 deficiency induced megaloblastic anemia, erythroblastic hypoplasia and aplastic anemia.
    Z Kinderheilkd, 1975 · Design: not stated · abstract only (PubMed) · unknown
    PMID 1130121
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:A high negative correlation (coefficient similar to 0.9) between increased 59Fe absorption from a diagnostic 0.56 mg 59Fe2+ dose and the depletion of available storage iron was observed in menstruating and pregnant women, fullterm and premature infants, blood donors, patients with infections, inflammations, tumors, hepatic cirrhosis, gastric surgery, increased urogenital or gastrointestinal blood loss.
    • Key findings · abstract:The increased diagnostic 59Fe2+ absorption is a reliable and sensitive indicator of at least depleted iron stores or prelatent iron deficiency as caused by iron malnutrition or maldigestion, i[excerpt truncated in our database — see source]
74. HumanCharacterization of a cobalamin-binding plasma protein from a patient with hepatoma.
    Scand J Clin Lab Invest, 1975 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 174188DOI 10.1080/00365517509095798
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:A cobalamin-binding protein has been purified by affinity chromatography from plasma of a patient with hepatoma and a 10,000-fold increase in the concentration of the plasma cobalamin-binding capacity.
    • Key findings · abstract:The molar absorption coefficient of cyanocobalamin bound to the protein was determined to be 36,000 at 362 nm.
    • Relative bioavailability · abstract:A cobalamin-binding protein has been purified by affinity chromatography from plasma of a patient with hepatoma and a 10,000-fold increase in the concentration of the plasma cobalamin-binding capacity.
75. HumanVitamin B12 absorption--a study of intraluminal events in control subjects and patients with tropical sprue.
    Gut, 1975 · Design: not stated · abstract only (PubMed) · open access (bronze)
    PMID 3457DOI 10.1136/gut.16.12.988PMC1413170 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The intraluminal fate of orally administered radioactive vitamin B12 has been studied in control subjects with normal vitamin B12 absorption and those with vitamin B12 malabsorption due to tropical sprue.
    • Key findings · abstract:In subjects with vitamin B12 malabsorption due to tropical sprue, the results were identical with the control subjects.
    • Key findings · abstract:Bacteriological studies showed a statistically significant correlation between both the number of flora in the jejunum and the number of bacteroides in both the jejunum and ileum and vitamin B12 malabsorption.
    • Key findings · abstract:In patients with tropical sprue who have normal intrinsic f[excerpt truncated in our database — see source]
76. HumanVitamin B12 absorption in patients with continent ileostomy.
    Scand J Gastroenterol, 1975 · Design: not stated · n: 34 patients · abstract only (PubMed) · unknown
    PMID 1124347
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Vitamin B12 absorption was studied in 34 patients, 10 months to 6 years after construction of a continent ileostomy.
    • Key findings · abstract:Normal Schilling test values (greater than 10 percent) were obtained in 21 of the cases after a single determination.
    • Key findings · abstract:Repeated tests showed a normal B12 absorption in 8 of the 13 patients who had revealed a Schilling test value below 10 percent at the first determination.
    • Key findings · abstract:When vitamin B12-intrinsic factor complex was instilled directly into the reservoir in 3 patients, it was found that the vitamin was absorbed by the mucous membrane of the reservoir.
    • Key findings · abstract:The construction of[excerpt truncated in our database — see source]
    • Fractional absorption · abstract:When vitamin B12-intrinsic factor complex was instilled directly into the reservoir in 3 patients, it was found that the vitamin was absorbed by the mucous membrane of the reservoir.
77. HumanVitamin B12 absorption after resection of ileum in childhood.
    Arch Dis Child, 1974 · Design: not stated · n: 10 infants · abstract only (PubMed) · open access (bronze)
    PMID 4217126DOI 10.1136/adc.49.12.932PMC1649116 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Impaired absorption of vitamin B12 has been shown by a whole body counter technique in 7 of 10 infants and children who had resection of over 45 cm of ileum.
    • Key findings · abstract:Absorption was normal in 2 patients who had 15 cm or more terminal ileum remaining.
    • Key findings · abstract:If absorption was abnormal the serum level of vitamin B12 did not fall below the lower limit of the normal range for several years, puberty being a particularly vulnerable time.
    • Key findings · abstract:Though the site and length of the resection often suggested whether vitamin B12 deficiency was likely to occur, an absorption test was necessary for accurate prediction and t[excerpt truncated in our database — see source]
78. HumanVitamin B12 absorption in some neurological and neuroendocrine disorders.
    J Clin Pathol, 1970 · Design: not stated · abstract only (PubMed) · open access (bronze)
    PMID 5483383DOI 10.1136/jcp.23.7.563PMC476836 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:An assessment of vitamin B(12) absorption in neurological patients has been made by both serum and urine counting of (57)Co cyanocobalamin during the conventional Schilling test.
79. HumanStudies on the 57Co vitamin B12 plasma level absorption test.
    J Clin Pathol, 1970 · Design: not stated · n: 163 patients · abstract only (PubMed) · open access (bronze)
    PMID 5483384DOI 10.1136/jcp.23.7.569PMC476837 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Results of the (57)Co vitamin B(12) plasma level absorption test are described in 163 patients.
    • Key findings · abstract:Injection of 1,000 mug of unlabelled vitamin B(12) during the test augmented plasma levels in patients with normal absorption but tests without this injection gave satisfactory differentiation between the normal and malabsorption ranges.
80. HumanEffect of vitamin B12 and folic acid deficiency on small intestinal absorption.
    J Clin Pathol, 1969 · Design: not stated · abstract only (PubMed) · open access (bronze)
    PMID 5364438DOI 10.1136/jcp.22.5.551PMC474245 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Malabsorption of both xylose and vitamin B(12) returned to normal in one patient after treatment of a megaloblastic anaemia due to dietary deficiency of folic acid.
    • Key findings · abstract:Impaired absorption of vitamin B(12) was corrected by vitamin B(12) therapy in the other two patients.
    • Key findings · abstract:In the third patient the small intestinal defect was secondary to pernicious anaemia, and in a group of 98 other patients with pernicious anaemia intrinsic factor did not improve vitamin B(12) absorption in six, and only partially corrected absorption in 30.
81. HumanVitamin B12 absorption studies: effect of parenteral non-radioactive B12 on serum level of 57CO vitamin B12.
    J Clin Pathol, 1967 · Design: not stated · abstract only (PubMed) · not checked (off-topic)
    PMID 5602975DOI 10.1136/jcp.20.5.687PMC473551 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The intestinal absorption of (57)Co vitamin B(12) has been measured by counting the radioactivity in the serum, and the effect of the parenteral administration of 1 mg. non-radioactive vitamin B(12) two hours after the oral dose has been studied.
    • Key findings · abstract:When parenteral vitamin B(12) was not given, the mean radioactivity in the serum was lower in both patients with pernicious anaemia and in control subjects, and the results in the patients with pernicious anaemia were more definitive.
    • Key findings · abstract:This is the simplest and most convenient method of measuring vitamin B(12) absorption.
82. HumanTHE URINARY EXCRETION AND TISSUE RETENTION OF CYANOCOBALAMIN BY SUBJECTS GIVEN REPEATED PARENTERAL DOSES.
    J Clin Pathol, 1964 · Design: not stated · abstract only (PubMed) · not checked (off-topic)
    PMID 14099998DOI 10.1136/jcp.17.1.31PMC480666 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The urinary excretion of injected cyanocobalamin was studied in 30 previously untreated vitamin B(12)-deficient patients by measuring the urinary radioactivity after repeated injections of (58)Co vitamin B(12).
    • Key findings · abstract:The excretion of radioactivity after parenteral infections of (58)Co vitamin B(12) was usually complete within 24 hours but exceptions to this were seen.
83. PrimateAbsorption of biliary cobalamin in baboons following total gastrectomy.
    J Lab Clin Med, 1982 · Design: not stated · abstract only (PubMed) · unknown
    PMID 7130832
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Retention of biliary cobalamin and an aqueous solution of cyanocobalamin was measured in normal baboons and in baboons after total gastrectomy by using 57Co-labeled biliary cobalamin and 58C0-cyanocobalamin, with and without baboon gastric juice containing intrinsic factor.
84. PigBioavailability of Vitamin B12 from Dairy Products Using a Pig Model.
    Nutrients, 2018 · Design: crossover · full text (Europe PMC XML) + abstract · open access (gold)
    PMID 30134590DOI 10.3390/nu10091134PMC6163222 (free full text)PDF
    Verification: full text read; no PK numbers matched
    • Key findings · abstract:The present study compares the bioavailability of vitamin B12 (B12) of dairy products or synthetic B12, using the pig as an experimental model for humans.
    • Key findings · abstract:Eleven pigs were used in a cross-over design to assess the net portal drained viscera (PDV) flux of blood plasma B12 after ingestion of tofu (TF; devoid of B12), Swiss cheese (SC), Cheddar cheese (CC), yogurt (YG), and synthetic B12 (TB12;[excerpt truncated in our database — see source]
    • Key findings · abstract:PDV blood plasma flow for SC and CC were higher than for TF and TB12 (p ≤ 0.04) whereas YG was higher than TF (p = 0.05).
    • Key findings · abstract:Porto-arterial difference of blood plasma B12 concentrations were higher for[excerpt truncated in our database — see source]
    • Food effect · abstract:Cumulative net PDV flux of B12 for SC, TB12, and CC were 2.9, 4.4, and 8.3 µg 23 h post-meal, corresponding to a bioavailability of 11.6%, 17.5%, and 33.0%, respectively.
85. PigBioavailability of dietary cyanocobalamin (vitamin B12) in growing pigs.
    J Anim Sci, 2010 · Design: crossover · n: 3 pigs · abstract only (PubMed) · closed/paywalled
    PMID 20709870DOI 10.2527/jas.2010-2979
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The present project aimed to estimate bioavailability of dietary vitamin B(12), for which little information is available in growing pigs.
    • Key findings · abstract:Two approaches, each using 2 quantities of dietary cyanocobalamin, were compared; the first was based on whole body retention for 8 d and the second was based on nycthemeral portal net flux of vitamin B(12).
    • Key findings · abstract:The whole body retention of vitamin B(12) was greater (P = 0.02) in B(12)-250 than B(12)-25 pigs, but the corresponding bioavailability was estimated to be 5.3 and 38.2%, respectively.
    • Key findings · abstract:Postprandial nycthemeral arterial plasma concentrations of vit[excerpt truncated in our database — see source]
    • Food effect · abstract:The remaining 2 piglets were fed 25 (B(12)-25) or 250 (B(12)-250) μg daily of cyanocobalamin for 8 d.
    • Food effect · abstract:In trial 2, 11 pigs (35.1 ± 4.0 kg of BW and 75.4 ± 5.9 d of age) fed a diet unsupplemented with vitamin B(12) from weaning at 28 d of age were surgically equipped with catheters in the portal vein and carotid artery and an ultrasonic flow probe around the portal vein.
    • Food effect · abstract:Postprandial nycthemeral arterial plasma concentrations of vitamin B(12) reached minimum values (P < 0.01) between 15 and 18 h postmeal that were 29.6, 15.6, and 10.0% less than the premeal values for B(12)-0, B(12)-25, and
86. PigVitamin B12 absorption in the neonatal piglet. 1. Studies in vivo on the influence of the vitamin B12-binding protein from sows' milk on the absorption of vitamin B12 and related compounds.
    Br J Nutr, 1985 · Design: not stated · abstract (PubMed); full-text PDF saved · open access (bronze)
    PMID 4063308DOI 10.1079/bjn19850108PDF
    Verification: full-text auto-extracted verbatim snippets with location; needs human check
    • Key findings · abstract:The influence of this 'binder' on the uptake and retention of cyanocobalamin and two natural analogues (cobinamide and Co-alpha-[2-methyladenyl]cobamide) was investigated with neonatal piglets.
    • Key findings · abstract:Retention of a single oral dose of cyano[58Co]cobalamin given before 7 d of age was consistently higher with suckled than with early-weaned piglets, as determined by measurement of whole-body radioactivity.
    • Key findings · abstract:Efficiency of retention declined with age, more rapidly in early-weaned than in suckled animals; when the dose was given at 14 d approximately 30% was retained by both groups.
    • Key findings · abstract:The influence of[excerpt truncated in our database — see source]
    • Food effect · full text, p.3:pe described by Braude et al. (1969). The diet given daily to each piglet was divided into three 100ml portions, placed in stainless-steel dishes and fed at 09.00, 13.00 and 18.00 hours. The basal diet, containing dried skimmed milk (146 g/l) and soya-bean oil (54 g/l), was homogenized and pasteurized and supplemented with fat-soluble vitamins, as described by Newport (1 980). Sows’ milk was obtai
87. PigIntrinsic factor-mediated absorption of cobalamin by guinea pig ileal cells.
    J Clin Invest, 1983 · Design: not stated · abstract only (PubMed) · open access (bronze)
    PMID 6826716DOI 10.1172/jci110788PMC436891 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:To investigate the fate of intrinsic factor and cobalamin during cobalamin absorption, we incubated enterocytes isolated from guinea pig ileum for periods of up to 30 min with (57)Co-labeled cyano-cobalamin bound either to human intrinsic factor or to rabbit intrinsic factor biosynthetically labeled with [(35)S]methionine.
88. PigSubcellular localisation of vitamin B12 during absorption in the guinea-pig ileum.
    Gut, 1981 · Design: not stated · abstract only (PubMed) · open access (bronze)
    PMID 7286777DOI 10.1136/gut.22.8.617PMC1420053 (free full text)
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The subcellular distribution of vitamin B12 was studied during its absorption in the guinea-pig ileum.
    • Key findings · abstract:These findings are consistent with vitamin B12 absorption by receptor-mediated endocytosis.
    • Food effect · abstract:Animals were fed either (57Co) or (58Co) cyanocobalamin and killed two or four hours later.
89. RodentDistinct intestinal adaptation for vitamin B12 and bile acid absorption revealed in a new mouse model of massive ileocecal resection.
    Biol Open, 2017 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
    PMID 28818841DOI 10.1242/bio.024927PMC5612230 (free full text)
    Verification: full-text auto-extracted verbatim snippets with location; needs human check
    • Key findings · abstract:Cubn mRNA and its protein product, which play an essential role in vitamin B12 absorption in the ileum, are not compensatory up-regulated in any part of the remnant intestine, demonstrating a clear contrast with post-operative up-regulation of genes involved in bile acid absorption.
    • Food effect · full text, Section 'Diets and operation':They were fasted for 12 h prior to surgery, but had free access to water.
90. RodentAbsorption and retention of free and milk protein-bound cyano- and hydroxocobalamins. An experimental study in rats.
    Biochimie, 2016 · Design: not stated · n: n = 15 · abstract only (PubMed) · open access (hybrid)
    PMID 26626348DOI 10.1016/j.biochi.2015.11.024
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:We compared absorption of free or rbTC-bound CN[(57)Co]Cbl added to cows' milk and analogous absorption of OH[(57)Co]Cbl, free or rbTC-bound, to absorption of free CN[(57)Co]Cbl, (n = 10 in each group).
    • Key findings · abstract:Absorption increased in the first 24 h with no further tissue accumulation during the subsequent 24 h.
    • Key findings · abstract:Accumulation of free CNCbl and (OHCbl) was 1.4, (4.1) (liver); 20.2, (16.4) (kidney); and 0.05, (0.02) (plasma)% 24 h after administration.
    • Key findings · abstract:While total accumulations of CNCbl and OHCbl were equal, distributions between liver, kidney, and plasma showed significant differences (p < 0.0001;[excerpt truncated in our database — see source]
91. RodentIn vivo application of chitosan to improve bioavailability of cyanocobalamin, a form of vitamin B12, following intraintestinal administration in rats.
    Int J Pharm, 2015 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 25681732DOI 10.1016/j.ijpharm.2015.02.016
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The effect of chitosan on the intestinal absorption of cyanocobalamin (VB12), a stable form of vitamin B12, was investigated in vivo in rats, with the aim of improving the oral bioavailability of VB12 for anemia treatment in patients with gastrectomy.
    • Key findings · abstract:The bioavailability was evaluated based on the plasma concentration profile of VB12 following intraintestinal administration of the VB12 solution containing chitosan at various concentrations.
    • Key findings · abstract:The bioavailability of VB12 was 0.6±0.2% when the chitosan-free VB12 solution was administered, while it increased to 10.5±3.3% when chitosan was disso[excerpt truncated in our database — see source]
    • Fractional absorption · abstract:The bioavailability of VB12 increases with the chitosan concentration, in which chitosan seems to augment the amount of VB12 absorbed without affecting the absorption rate constant of VB12.
92. RodentPharmacokinetics of high doses of cyanocobalamin administered by intravenous injection for 26 weeks in rats.
    Clin Exp Pharmacol Physiol, 2005 · Design: not stated · abstract only (PubMed) · not checked (off-topic)
    PMID 15730428DOI 10.1111/j.1440-1681.2005.04145.x
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Cyanocobalamin plasma levels were quantified by HPLC on days 1, 85 and 182 of treatment and were analysed by means of non-compartment pharmacokinetic (PK) analysis.
    • Key findings · abstract:In addition, population PK analysis was used to fit cyanocobalamin plasma concentrations to time by means of a two-compartment model for intravascular administration. 3.
93. RodentHydroxocobalamin uptake into the cerebrospinal fluid after nasal and intravenous delivery in rats and humans.
    J Drug Target, 2003 · Design: not stated · n: n=8 · abstract only (PubMed) · not checked (off-topic)
    PMID 14668053DOI 10.1080/10611860310001640075
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:This same transport route is confirmed by the cumulative AUC-time profiles in CSF and plasma, demonstrating a 30 min delay between plasma absorption and CSF uptake of hydroxocobalamin in rats and in a comparative human study.
    • AUC · abstract:This same transport route is confirmed by the cumulative AUC-time profiles in CSF and plasma, demonstrating a 30 min delay between plasma absorption and CSF uptake of hydroxocobalamin in rats and in a comparative human study.
94. RodentOral absorption of peptides through the cobalamin (vitamin B12) pathway in the rat intestine.
    Pharm Res, 2000 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 10990201DOI 10.1023/a:1007556108673
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:METHODS: To enable acquisition of quantitative absorption data of Cbl-peptides, metabolically stable octapeptides (DP3), with (Cbl-Hex-DP3) or without a hexyl spacer (Cbl-DP3), were coupled to Cbl and radiolabeled.
    • Key findings · abstract:Biological recognition of Cbl-peptides was studied in the physiological order: binding by Intrinsic Factor (IF), recognition and transport of the IF-complexes by IF-Cbl receptors (IFCR) on Caco-2 monolayers and oral absorption of the Cbl-conjugates in the rat.
    • Key findings · abstract:Binding was saturable and could be inhibited by a 20-fold excess of IF-Cbl, but not of Non-intrinsic Factor (NIF)-Cbl. |[excerpt truncated in our database — see source]
    • Relative bioavailability · abstract:Binding was saturable and could be inhibited by a 20-fold excess of IF-Cbl, but not of Non-intrinsic Factor (NIF)-Cbl.
    • Relative bioavailability · abstract:Simultaneous administration of a >10(5)-fold excess of unlabeled Cbl reduced uptake of all compounds to <4%.
95. RodentIntestinal uptake and release of cobalamin complexed with rat intrinsic factor.
    Am J Physiol, 1985 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 3976892DOI 10.1152/ajpgi.1985.248.3.G326
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:When cathepsins were added, the Cbl released was no greater than could be attributed to pH 5.0 alone.
96. RodentThe uptake of R-type cobalamin-binding protein by isolated rat liver cells.
    Biochim Biophys Acta, 1982 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 7082685DOI 10.1016/0167-4889(82)90013-1
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:Vitamin B-12 bound to plasma transcobalamin I, however, was not taken up unless the protein was desialylated by neuraminidase from Vibrio cholerae.
    • Key findings · abstract:The uptake of iodinated pure granulocyte-binding protein, saturated with cobalamin, reached 100% and was accompanied by increasing intracellular proteolytic degradation of the binding protein.
97. RodentHumoral regulation of vitamin B12 absorption by pregnant mouse small intestine.
    Gastroenterology, 1977 · Design: not stated · abstract only (PubMed) · unknown
    PMID 849818
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:In vivo experiments in which pregnant mice were fed an oral dose of 40 ng of [57Co]B12 demonstrated that there was a progressive increase in B12 absorption in the 3rd week of pregnancy.
    • Key findings · abstract:Hourly injections of serum from mice in late pregnancy, or from a female at the 37th week of gestation, maintained IF-B12 binding at levels reached during pregnancy, whereas nonpregnant serum was ineffective.
    • Food effect · abstract:In vivo experiments in which pregnant mice were fed an oral dose of 40 ng of [57Co]B12 demonstrated that there was a progressive increase in B12 absorption in the 3rd week of pregnancy.
98. RodentUptake of hydroxocobalamin by rat liver mitochondria. Binding to a mitochondrial protein.
    J Biol Chem, 1976 · Design: not stated · abstract only (PubMed) · unknown
    PMID 977589
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The uptake system is saturable and unidirectional, leading to inside/outside concentration ratios of 17.
    • Key findings · abstract:The process also exhibits specificity: cyano[57Co]cobalamin is taken up less rapidly and to a lesser extent than hydroxocobalamin; methylcobalamin and adenoslcobalamin inhibit hydroxocobalamin uptake markedly, while cyanocobalamin does not.
99. Other animalCyanocobalamin-loaded dissolving microneedles for enhanced transdermal delivery: development, characterization, and pharmacokinetic evaluation.
    Biomed Microdevices, 2025 · Design: not stated · abstract only (PubMed) · closed/paywalled
    PMID 40310523DOI 10.1007/s10544-025-00747-0
    Verification: abstract-only auto-extract; unverified
    • Key findings · abstract:The in-vivo pharmacokinetic evaluation in Wistar rats demonstrates that CNBL-MNs-2 exhibited a larger area under the curve (AUC₀-t) (61.57 ± 4.23 ng·h/mL) than the IP injection (37.04 ± 5.83 ng·h/mL), indicating significant (p > 0.05) increase in systemic availability and sustained release.
    • Key findings · abstract:The Cmax of CNBL-MNs-2 (6.10 ± 0.533 ng/mL) was comparable to that of the IP injection (6.20 ± 1.5 ng/mL), confirming efficient systemic absorption via the microneedle system.
    • Cmax · abstract:The Cmax of CNBL-MNs-2 (6.10 ± 0.533 ng/mL) was comparable to that of the IP injection (6.20 ± 1.5 ng/mL), confirming efficient systemic absorption via the microneedle system.
    • Tmax · abstract:Additionally, Tmax was significantly (p > 0.05) prolonged with CNBL-MNs-2 (8 h) compared to the IP injection (2 h), suggesting a slower, more controlled CNBL release.
    • AUC · abstract:The in-vivo pharmacokinetic evaluation in Wistar rats demonstrates that CNBL-MNs-2 exhibited a larger area under the curve (AUC₀-t) (61.57 ± 4.23 ng·h/mL) than the IP injection (37.04 ± 5.83 ng·h/mL), indicating significant (p > 0.05) increase in systemic availability and sustained release.
100. Other animalSalvage pathway of vitamin B12 absorption in chickens with mutant tumor virus a receptor.
     Poult Sci, 2025 · Design: not stated · abstract only (PubMed) · not checked (off-topic)
     PMID 39754921DOI 10.1016/j.psj.2024.104744PMC11758413 (free full text)
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:Naturally occurring genetic variants in the TVA gene determine susceptibility or resistance to ALV-A and -K, but the effects of these mutated TVA on vitamin B12 uptake have not been investigated systemically.
     • Key findings · abstract:This study investigates the relationship between the various genotypes of TVA alleles and uptake of vitamin B12 in chickens.
     • Key findings · abstract:A protein interaction model suggested that mutant TVAs (i.e., TVASNP, TVAR) may have reduced ability to take up vitamin B12 due to a disrupted LDL-A domain, a pivotal region involved in vitamin B12 uptake; however, we found no significant difference in absorptio[excerpt truncated in our database — see source]
101. Other animalCo-encapsulation of vitamins B6 and B12 using zein/gum arabic nanocarriers for enhanced stability, bioaccessibility, and oral bioavailability.
     J Food Sci, 2024 · Design: not stated · abstract only (PubMed) · open access (bronze)
     PMID 39656779DOI 10.1111/1750-3841.17567
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:The present study aimed to fabricate a co-deliver system using zein/gum arabic (GA) polymers for enhanced stability and bioavailability of vitamins (B6 and B12).
     • Key findings · abstract:In Caco-2 cells, the cellular uptake of vitamins was higher from nanoforms compared to the free-forms.
     • Key findings · abstract:Further, oral administration of PC-ZG NPs in rats exhibited 4.8- and 2.2-fold increases in relative bioavailability of vitamins B6 and B12, respectively.
     • Key findings · abstract:A significant reduction of plasma homocysteine level (p ˂ 0.05) in the treated group was also observed.
     • Relative bioavailability · abstract:Further, oral administration of PC-ZG NPs in rats exhibited 4.8- and 2.2-fold increases in relative bioavailability of vitamins B6 and B12, respectively.
102. Other animalThe passive diffusion improvement of Vitamin B12 intestinal absorption by Gelucire that fit for commercialized production.
     Saudi Pharm J, 2023 · Design: not stated · full text (Europe PMC XML) + abstract · open access (hybrid)
     PMID 37234351DOI 10.1016/j.jsps.2023.04.024PMC10206182 (free full text)
     Verification: full-text auto-extracted verbatim snippets with location; needs human check
     • Key findings · abstract:Moreover, the absorption of VB12 needs to be mediated by intrinsic factor on the gastrointestinal (GI) track.
     • Key findings · abstract:The abnormalities in the stomach or lack of such intrinsic factors may result in poor oral absorption of VB12.
     • Key findings · abstract:Thus, the objectives of the present study were to increase the VB12 intestinal absorption by conventional excipients of Gelucire 44/14 (G44/14) or Labrasol, which could be potentially formulated as a cost effect balanced product.
     • Key findings · abstract:The in vitro Caco-2 cell model was applied for the absorption study.
     • Key findings · abstract:The results suggested that G44/14 could significantly enhance the intest[excerpt truncated in our database — see source]
     • Food effect · full text, Section 'Preparation of everted gut sac':Briefly, male Sprague-Dawley rats (body weight 180–210 g) were selected and fasted for 24 h (free access to water) before the experiment.
103. Other animalInvestigation of the potential of Glycyrrhiza glabra as a bioavailability enhancer of Vitamin B12.
     Front Nutr, 2022 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
     PMID 36386946DOI 10.3389/fnut.2022.1038902PMC9650095 (free full text)
     Verification: full-text auto-extracted verbatim snippets with location; needs human check
     • Key findings · abstract:Inadequate consumption of B12 rich diet and low bioavailability (due to diet based/physiological factors) are linked to the deficiency of Vitamin B12 inside the body.
     • Key findings · abstract:Thus, the present study aimed to examine the potential of ethanolic extract obtained from G. glabra roots to enhance the bioavailability of Vitamin B12.
     • Key findings · abstract:The effect of ethanolic extract of G. glabra (GgEtOH) on intestinal absorption enhancement of B12 was assessed in vitro on Caco-2 and ex-vivo everted gut sac models.
     • Key findings · abstract:GgEtOH significantly enhanced the permeation (Papp) of B12 by 2-5 fold in vitro (25, 50, and 100 μg/ml conce[excerpt truncated in our database — see source]
     • Cmax · abstract:The pharmacokinetic parameters of B12 such as Cmax, AUC, Tmax, etc. were also significantly elevated in vivo upon oral administration of B12 (1 mg/kg dose) in combination with GgEtOH (100 and 1,000 mg/kg dose).
     • Tmax · abstract:The pharmacokinetic parameters of B12 such as Cmax, AUC, Tmax, etc. were also significantly elevated in vivo upon oral administration of B12 (1 mg/kg dose) in combination with GgEtOH (100 and 1,000 mg/kg dose).
     • AUC · abstract:The pharmacokinetic parameters of B12 such as Cmax, AUC, Tmax, etc. were also significantly elevated in vivo upon oral administration of B12 (1 mg/kg dose) in combination with GgEtOH (100 and 1,000 mg/kg dose).
     • Relative bioavailability · abstract:GgEtOH significantly enhanced the permeation (Papp) of B12 by 2-5 fold in vitro (25, 50, and 100 μg/ml concentrations) and ex-vivo (250 and 500 μg/ml concentrations).
     • Cmax · full text, Section 'In vivo Vitamin B12 pharmacokinetics stu':Although, GgEtOH at 100 mg/kg dose significantly increased the Cmax and AUC, it did not contribute to the increment in t1/2, Tmax, AUC 0–inf and MRT of B12.
     • Cmax · full text, Section 'In vivo Vitamin B12 pharmacokinetics stu':However, GgEtOH at 1,000 mg/kg dose caused significant enhancement of Cmax and AUC compared to the control group.
     • Cmax · full text, TABLE 1:B12 alone (1mg/kg) B12+GgEtOH (100 mg/kg) B12+GgEtOH (1000 mg/kg) t1/2 121.27 ± 34.74 89.21 ± 54.58 208.65 ± 79.76 Tmax (mins.) 26.25 ± 6.71 30 18.75 ± 6.71* Cmax (ng/ml) 116.94 ± 8.42 218.86 ± 15.73*** 222.42 ± 21.24*** AUC 0–120 9731.214 ± 621.1 15282.49 ± 1986.72*** 20165.09 ± 813.73*** AUC 0–inf 21370.60 ± 3776.34 29205.84 ± 15579.16 66503.206 ± 21035.76*** MRT 187.54 ± 52.73 143.44 ± 78.37 31
     • Tmax · full text, Section 'In vivo Vitamin B12 pharmacokinetics stu':Although, GgEtOH at 100 mg/kg dose significantly increased the Cmax and AUC, it did not contribute to the increment in t1/2, Tmax, AUC 0–inf and MRT of B12.
     • Tmax · full text, Section 'In vivo Vitamin B12 pharmacokinetics stu':In B12+GgEtOH 1,000 mg/kg treated group, the Tmax of B12 was significantly improved and was attained in lesser duration (18.75 min) than B12 alone treated group (26.25 min) (Table 1).
     • Tmax · full text, TABLE 1:B12 alone (1mg/kg) B12+GgEtOH (100 mg/kg) B12+GgEtOH (1000 mg/kg) t1/2 121.27 ± 34.74 89.21 ± 54.58 208.65 ± 79.76 Tmax (mins.) 26.25 ± 6.71 30 18.75 ± 6.71* Cmax (ng/ml) 116.94 ± 8.42 218.86 ± 15.73*** 222.42 ± 21.24*** AUC 0–120 9731.214 ± 621.1 15282.49 ± 1986.72*** 20165.09 ± 813.73*** AUC 0–inf 21370.60 ± 3776.34 29205.84 ± 15579.16 66503.206 ± 21035.76*** MRT 187.54 ± 52.73 143.44 ± 78.37 31
     • AUC · full text, Section 'In vivo Vitamin B12 pharmacokinetics stu':Although, GgEtOH at 100 mg/kg dose significantly increased the Cmax and AUC, it did not contribute to the increment in t1/2, Tmax, AUC 0–inf and MRT of B12.
     • AUC · full text, Section 'In vivo Vitamin B12 pharmacokinetics stu':However, GgEtOH at 1,000 mg/kg dose caused significant enhancement of Cmax and AUC compared to the control group.
     • AUC · full text, TABLE 1:B12 alone (1mg/kg) B12+GgEtOH (100 mg/kg) B12+GgEtOH (1000 mg/kg) t1/2 121.27 ± 34.74 89.21 ± 54.58 208.65 ± 79.76 Tmax (mins.) 26.25 ± 6.71 30 18.75 ± 6.71* Cmax (ng/ml) 116.94 ± 8.42 218.86 ± 15.73*** 222.42 ± 21.24*** AUC 0–120 9731.214 ± 621.1 15282.49 ± 1986.72*** 20165.09 ± 813.73*** AUC 0–inf 21370.60 ± 3776.34 29205.84 ± 15579.16 66503.206 ± 21035.76*** MRT 187.54 ± 52.73 143.44 ± 78.37 31
     • Food effect · full text, Section 'In vivo Vitamin B12 pharmacokinetics stu':Prior experiment, animals were fasted for 18–24 h with access to water only.
     • Form comparison · full text, Section 'Ex vivo Vitamin B12 permeability study':As shown in Figure 3B, increased apparent permeability (Papp) values of B12 were obtained for sacs incubated with B12+GgEtOH (250 and 500 μg/ml) as compared to B12 alone.
     • Form comparison · full text, Section 'In vivo Vitamin B12 pharmacokinetics stu':As shown in Figure 4, the plasma concentration of Vitamin B12 increased in mice treated with B12+GgEtOH 100 mg/kg and B12+GgEtOH 1,000 mg/kg compared to mice treated with B12 only.
     • Form comparison · full text, Section 'In vivo Vitamin B12 pharmacokinetics stu':However, GgEtOH at 1,000 mg/kg dose caused significant enhancement of Cmax and AUC compared to the control group.
104. Other animalA pilot study comparing the pharmacokinetics of injectable cyanocobalamin and hydroxocobalamin associated with a trace mineral injection in cattle.
     J Vet Pharmacol Ther, 2021 · Design: not stated · full text (Europe PMC XML) + abstract · open access (hybrid)
     PMID 33686699DOI 10.1111/jvp.12967PMC8252089 (free full text)
     Verification: full text read; no PK numbers matched
     • Key findings · abstract:Sheep and human studies have demonstrated the superiority of a single dose of hydroxocobalamin (OHB12) over cyanocobalamin (CNB12) in maintaining high levels of cobalamin in plasma and liver.
     • Key findings · abstract:Cyanocobalamin had lower retention in plasma and liver than OHB12 (p < .05).
     • Key findings · abstract:Cobalamin levels peaked in plasma by 8 h after treatment in both groups.
     • Key findings · abstract:However, OHB12 reached a higher peak compared to CNB12.
     • Key findings · abstract:Levels of cobalamin in plasma dropped closer to baseline levels 24 h after CNB12 treatment while OHB12 maintained higher concentrations.
105. Other animalThe avian retroviral receptor Tva mediates the uptake of transcobalamin bound vitamin B12 (cobalamin).
     J Virol, 2021 · Design: stable-isotope · abstract only (PubMed) · open access (green)
     PMID 33504597DOI 10.1128/JVI.02136-20PMC8103681 (free full text)
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:Previously, we have noted an intriguing resemblance and orthology between the chicken gene coding for Tva and the human gene coding for CD320, a receptor involved in cellular uptake of transcobalamin (TC) in complex with vitamin B12/cobalamin (Cbl).Here we show that both the transmembrane and the glycosylphosphatidylinositol (GPI)-anchored form of Tva in the chicken cell line DF-1 promotes the uptake of Cbl with help of expressed and purified chicken TC.
106. Other animal14C-Cobalamin Absorption from Endogenously Labeled Chicken Eggs Assessed in Humans Using Accelerator Mass Spectrometry.
     Nutrients, 2019 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
     PMID 31500393DOI 10.3390/nu11092148PMC6769442 (free full text)PDF
     Verification: full-text auto-extracted verbatim snippets with location; needs human check
     • Key findings · abstract:Traditionally, the bioavailability of vitamin B-12 (B12) from in vivo labeled foods was determined by labeling the vitamin with radiocobalt (57Co, 58Co or 60Co).
     • Key findings · abstract:This required use of penetrating radioactivity and sometimes used higher doses of B12 than the physiological limit of B12 absorption.
     • Key findings · abstract:The aim of this study was to determine the bioavailability and absorbed B12 from chicken eggs endogenously labeled with 14C-B12 using accelerator mass spectrometry (AMS). 14C-B12 was injected intramuscularly into hens to produce eggs enriched in vivo with the 14C labeled vitamin.
     • Key findings · abstract:Bioavailability r[excerpt truncated in our database — see source]
     • Fractional absorption · abstract:The aim of this study was to determine the bioavailability and absorbed B12 from chicken eggs endogenously labeled with 14C-B12 using accelerator mass spectrometry (AMS). 14C-B12 was injected intramuscularly into hens to produce eggs enriched in vivo with the 14C labeled vitamin.
     • Fractional absorption · abstract:The total amount of B12 absorbed was limited to 0.5-0.8 μg (mean 0.55 ± 0.19 μg B12) and was relatively unaffected by the amount consumed.
     • Food effect · abstract:The eggs, which provided 1.4 to 2.6 μg of B12 (~1.1 kBq) per serving, were scrambled, cooked and fed to 10 human volunteers.
     • Cmax · full text, Table 2:Plasma absorption and clearance parameters for study subjects S1–S10. Subject B12 14C-B12 Cmax Tmax Plasma Plasma Dose Dose Plasma Plasma AUC 1 0–24 h AUC 1 0–168 h (μg) (kBq) (Bq/L) (h) (Bq·h/L) (Bq·h/L) S1 2.38 1.114 21.9 12 323 940 S2 1.66 0.777 17.4 15 250 657 S3 2.65 1.159 60.3 9 649 1745 S4 2.65 1.158 34.9 7 386 1241 S5 1.43 1.089 32.5
     • Cmax · full text, Section '3.2. Appearance of 14C Label in Plasma, ':14C first appeared in plasma approximately 4 h after ingestion of the labeled egg in all volunteers although peak plasma concentrations of 14C varied among participants (Figure 3).
     • Tmax · full text, Table 2:Plasma absorption and clearance parameters for study subjects S1–S10. Subject B12 14C-B12 Cmax Tmax Plasma Plasma Dose Dose Plasma Plasma AUC 1 0–24 h AUC 1 0–168 h (μg) (kBq) (Bq/L) (h) (Bq·h/L) (Bq·h/L) S1 2.38 1.114 21.9 12 323 940 S2 1.66 0.777 17.4 15 250 657 S3 2.65 1.159 60.3 9 649 1745 S4 2.65 1.158 34.9 7 386 1241 S5 1.43 1.089 32.5 11 41
     • AUC · full text, Table 2:Plasma absorption and clearance parameters for study subjects S1–S10. Subject B12 14C-B12 Cmax Tmax Plasma Plasma Dose Dose Plasma Plasma AUC 1 0–24 h AUC 1 0–168 h (μg) (kBq) (Bq/L) (h) (Bq·h/L) (Bq·h/L) S1 2.38 1.114 21.9 12 323 940 S2 1.66 0.777 17.4 15 250 657 S3 2.65 1.159 60.3 9 649 1745 S4 2.65 1.158 34.9 7 386 1241 S5 1.43 1.089 32.5 11 410 1649 S6 1.40 1.083 37.2 8 363 1185 S7 1.
     • AUC · full text, Section '3.2. Appearance of 14C Label in Plasma, ':Plasma area under the curve (AUC) for 0–24 h ranged from 250 to 649 Bq·h/L plasma with a mean AUC of 404 ± 106 Bq·h/L.
     • AUC · full text, Section '3.2. Appearance of 14C Label in Plasma, ':Plasma area under the curve (AUC) for 0–168 h ranged from 657 to 1785 Bq·h/L plasma with a mean AUC of 1294 ± 327 Bq·h/L.
     • Food effect · full text, Table A1:rotocol Dose 1 ODE PME OPE PPE ODB PMB (%) (%) (%) (%) (%) (%) Edwards [23] 1 0.5 µCi 57Co-B12 (IM) 52 52 8 11 35 37 Edwards [23] 2 0.5 µCi 57Co-B12 (FED) 33 32 5 4 18 19 Edwards [23] 3 0.072 µCi 60Co-B12 (IM) 63 59 11 12 45 41 Edwards [23] 4 0.072 µCi 60Co-B12 (FED) 36 37 7 5 30 27 Denton [24] 5 3 µg/d crystal B12 (IM) 33 28 4 4 NA NA Denton [24] 6 3 µg/d crystal B12 (FED) 20 15 1.5 1.3 NA NA
     • Form comparison · full text, Section '3.3. Calculation of Bioavailability ':Mean % bioavailability values in subjects receiving low doses (1.43–1.66 μg) of total B12 and in subjects receiving high doses (2.38–2.65 μg) of total B12 were significantly different (40.3 ± 17.8% vs. 20.1 ± 5.4%, respectively; p = 0.04, Student’s t-test) (Figure 7A,C).
107. Other animalVitamin B12 and its binding proteins in milk from cow and buffalo in relation to bioavailability of B12.
     J Dairy Sci, 2019 · Design: not stated · abstract only (PubMed) · open access (bronze)
     PMID 30928264DOI 10.3168/jds.2018-15016
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:Milk is an important source of highly bioavailable vitamin B12 (cobalamin) in human nutrition.
     • Key findings · abstract:As the type of vitamin B12 binders may influence bioavailability of the vitamin, we examined vitamin B12 carriers in pooled milk specimens derived from European and Indian cow and buffalo herds.
     • Key findings · abstract:We tested (in vitro) the transfer of vitamin B12 from milk proteins to human carriers, involved in the intestinal uptake.
     • Key findings · abstract:The substitution of HC by less sturdy carriers is apparently more beneficial to human consumers as far as vitamin B12 bioavailability is concerned.
108. Other animalImaging Cobalamin Uptake within Malignant Breast Tumors In Vivo.
     Mol Imaging Biol, 2019 · Design: not stated · n: n = 11 · abstract only (PubMed) · not checked (off-topic)
     PMID 29931431DOI 10.1007/s11307-018-1232-9
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:Subsequent pulse chase (PC) experiments in nude mice burdened with the MDA-MB-231 triple-negative (TN) breast tumor xenograft measured the effect that pulses of AC or dexamethasone (DEX) had on [111In]AC uptake in both normal murine tissue and the TN breast tumor.
     • Key findings · abstract:Pulses of 2.0 μg of AC at 2, 8, or 24 h; or 40.0 μg of DEX at 24 h prior to injecting 0.5 μg of [111In]AC, increased mean tracer uptake in the MDA-MB-231 tumors by 26.4, 71.5, 92.6, and 49.1 %, respectively.
     • Key findings · abstract:Only the 2- and 24-h PC intervals concomitantly suppressed [111In]AC uptake in normal murine tissue while enhancing [111In]
109. Other animalHibiscus sabdariffa increases hydroxocobalamin oral bioavailability and clinical efficacy in vitamin B12 deficiency with neurological symptoms.
     Fundam Clin Pharmacol, 2016 · Design: not stated · abstract only (PubMed) · closed/paywalled
     PMID 27416488DOI 10.1111/fcp.12220
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:The aim of the study was to evaluate the bioavailability and clinical benefits of oral new formulation (HB12 ) of hydroxocobalamin (Hdrx) with Hibiscus sabdariffa (HS).
     • Key findings · abstract:In the clinical study, serum vitamin B12 level increased from 55.1 ± 36.9 to 1330 ± 335.5 pg/mL at day 10 and 431.0 ± 24.27 pg/mL at day 90, without overt adverse effects.
     • Key findings · abstract:In mice ileum, (i) intestinal bioavailability of Hdrx increased in dose-dependent manner with HB12 .
110. Other animalVitamin B12 absorption and metabolism in milk-fed lambs.
     N Z Vet J, 2009 · Design: not stated · n: n=2 · abstract only (PubMed) · closed/paywalled
     PMID 19252539DOI 10.1080/00480169.2009.36864
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:AIM: To quantify aspects of absorption and retention of vitamin B12 from milk in pre-ruminant lambs, and the possible effect of activation of dependent metabolic pathways (propionate-succinate) on vitamin B12 concentrations in tissues.
     • Key findings · abstract:Blood and liver samples were taken on Day -1 and at the end of the trial, and blood was also collected twice weekly, for measurement in plasma of vitamin B12, methylmalonic acid (MMA), and blood-binder transcobalamin II/haptocorrin.
     • Key findings · abstract:Blood and liver samples were taken at the start and end of the trial, and blood was also collected twice weekly, for measuremen[excerpt truncated in our database — see source]
     • Food effect · abstract:In Experiment 2, 12 milk-fed newborn lambs (n=2 or 3/group) were injected I/M with 0.2, 0.4, 0.8, 1.6 or 3.2 microg vitamin B12 and a further 12 were supplemented orally with 2, 4, 8, 16 or 32 microg vitamin B12, daily for 2 weeks.
     • Food effect · abstract:The coefficient of absorption of oral vitamin B12 in milk-fed lambs was low (<10%), and the ability of lambs to retain the vitamin even when tissues had physiologically low concentrations was poor.
111. Other animalSpray-dried powders as nasal absorption enhancers of cyanocobalamin.
     Biol Pharm Bull, 2001 · Design: not stated · abstract (PubMed); full-text PDF saved · open access (bronze)
     PMID 11767112DOI 10.1248/bpb.24.1411PDF
     Verification: full-text auto-extracted verbatim snippets with location; needs human check
     • Key findings · abstract:The highest absorption enhancement was observed with cellulose microcrystalline powders, which provided a 25% mean absolute bioavailability, followed by crospovidone and dextran microspheres formulations with mean bioavailability values of 14% and 7%, respectively.
     • Cmax · full text, p.2:ability was determined tion–time curve from 0 to 120 min (AUC0—120), peak concen- according to the equation reported by Staniforth24): %com- tration (Cmax), and time to reach the peak concentration (tmax) pressibility5100 · (Df2D0) / Df. after both intravenous and intranasal administration of Determination of Powder Moisture Moisture was mea- cyanocobalamin were calculated independently of kinetic
     • Cmax · full text, p.5:(Mean and 95% Confidence Interval or Mode and Range) lease is due to desorption rather than diffusion from the inte- rior of the particles. AUC0—120 Cmax tmax Formulation To study the in vivo enhancement effect of spray-dried (ng · min/ml) (ng/ml) (min) particles, SD-MC, SD-CP, and SD-DM formulations were SD-MC 6988.9 72.9 15 chosen to compare their bioavailability characteristics with (1812—12165
     • Tmax · full text, p.2:120 min (AUC0—120), peak concen- according to the equation reported by Staniforth24): %com- tration (Cmax), and time to reach the peak concentration (tmax) pressibility5100 · (Df2D0) / Df. after both intravenous and intranasal administration of Determination of Powder Moisture Moisture was mea- cyanocobalamin were calculated independently of kinetic sured in triplicate in 100-mg samples according
     • Tmax · full text, p.5:n and 95% Confidence Interval or Mode and Range) lease is due to desorption rather than diffusion from the inte- rior of the particles. AUC0—120 Cmax tmax Formulation To study the in vivo enhancement effect of spray-dried (ng · min/ml) (ng/ml) (min) particles, SD-MC, SD-CP, and SD-DM formulations were SD-MC 6988.9 72.9 15 chosen to compare their bioavailability characteristics with (1812—12165) (2
     • AUC · full text, p.2:rma-Test® PT-TD appa- Boil Radioassay (Chiron Diagnostics). ratus was employed to determine tapped density. Percentage The pharmacokinetic parameters area under the concentra- compressibility as a measure of flowability was determined tion–time curve from 0 to 120 min (AUC0—120), peak concen- according to the equation reported by Staniforth24): %com- tration (Cmax), and time to reach the peak conc
     • AUC · full text, p.5:Solution (Mean and 95% Confidence Interval or Mode and Range) lease is due to desorption rather than diffusion from the inte- rior of the particles. AUC0—120 Cmax tmax Formulation To study the in vivo enhancement effect of spray-dried (ng · min/ml) (ng/ml) (min) particles, SD-MC, SD-CP, and SD-DM formulations were SD-MC 6988.9 72.9 15 chosen to compare their bioavailability characteristics with (1
     • Food effect · full text, p.2:was carried out with a Spray-Drier at an inlet temperature of 150 °C. The suspen- nasal insufflator marketed for the nasal administration of sion was fed to the drier at a rate of 11 ml/min. An air flow sodium cromoglycate (Rinoflador, Fisons, Spain). Ten mil- rate of 800 l/h and an aspiration vacuum of 35 mbar were ligrams of each powder (1% w/w of cyanocobalamin) con- used. To compare with the p
     • Form comparison · full text, p.1:P), croscarmellose sodium (CC), and crospovidone recently, chitosan.16,17) Most of these water-absorbent and (CP) spray-dried powders are studied and compared with water-insoluble powdered nasal dosage forms have been pre- those of the corresponding freeze-dried powders to demon- pared by freeze-drying. This process produces an intense strate that spray-drying can be a suitable alternative to unio
112. Other animalPharmacokinetics of hydroxocobalamin in smoke inhalation victims.
     J Toxicol Clin Toxicol, 1996 · Design: clinical trial · abstract only (PubMed) · not checked (off-topic)
     PMID 8699553DOI 10.3109/15563659609013809
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:Serum hydroxocobalamin levels were followed from just before drug administration to six days after a single 5 g dose of hydroxocobalamin.
113. Other animalPharmacokinetics of hydroxocobalamin in dogs.
     J Neurosurg Anesthesiol, 1994 · Design: not stated · n: n = 6 · abstract only (PubMed) · closed/paywalled
     PMID 8012169DOI 10.1097/00008506-199404000-00006
     Verification: abstract-only auto-extract; unverified
114. Other animalStudies of cobalamin as a vehicle for the renal excretion of cyanide anion.
     J Lab Clin Med, 1990 · Design: not stated · abstract only (PubMed) · unknown
     PMID 2376694
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:To examine the ability of hydroxocobalamin (vitamin B12a, HO-Cbl) to counteract the toxicity of cyanide by promoting the renal excretion of cyanide anion, we studied the pharmacokinetics of HO-Cbl and cyanocobalamin (vitamin B12, CN-Cbl) given in high doses to dogs.
     • Key findings · abstract:After administration of intravenous bolus doses of HO-Cbl and CN-Cbl (5, 10, 25 mg/kg) to female foxhounds, peak plasma concentrations were attained within 1 minute, after which the cobalamins disappeared from plasma in a manner consistent with two-phase distribution and elimination kinetics.
     • Key findings · abstract:While mean t1/2 measurements for th[excerpt truncated in our database — see source]
     • Cmax · abstract:After administration of intravenous bolus doses of HO-Cbl and CN-Cbl (5, 10, 25 mg/kg) to female foxhounds, peak plasma concentrations were attained within 1 minute, after which the cobalamins disappeared from plasma in a manner consistent with two-phase distribution and elimination kinetics.
115. Other animalGastric and pancreatic intrinsic factor-mediated absorption of cobalamin in the dog.
     Am J Physiol, 1989 · Design: not stated · abstract only (PubMed) · closed/paywalled
     PMID 2782408DOI 10.1152/ajpgi.1989.257.3.G344
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:At 2 h, total uptake of cobalamin by ileal mucosa was significantly enhanced after prior binding to either gastric or pancreatic intrinsic factor compared with controls.
116. Other animalEffect of exocrine pancreatic insufficiency on cobalamin absorption in dogs.
     Am J Vet Res, 1989 · Design: not stated · abstract only (PubMed) · unknown
     PMID 2782706
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:The possibility that the canine pancreas might have an important role in the physiologic absorption of cobalamin (vitamin B12) has been explored by determining the effect of exocrine pancreatic insufficiency on cobalamin absorption and by examining the subsequent influence of bovine pancreatic enzymes and canine pancreatic juice.
     • Key findings · abstract:Cobalamin absorption was determined by oral administration of cyano[58Co]cobalamin and quantitation of radioactivity in blood, urine, and feces during 48 hours.
     • Key findings · abstract:Pancreatic duct ligation resulted in a significant (P less than 0.001) decrease in cobalamin absorption[excerpt truncated in our database — see source]
117. Other animalUptake of vitamin B12 by isolated ileal enterocytes.
     J Nutr Sci Vitaminol (Tokyo), 1984 · Design: not stated · abstract (PubMed); full-text PDF saved · open access (gold)
     PMID 6436453DOI 10.3177/jnsv.30.209PDF
     Verification: full-text auto-extracted verbatim snippets with location; needs human check
     • Key findings · abstract:Uptake of B12 by ileal cells was dependent upon IF and Ca2+.
     • Key findings · abstract:Incubation of ileal enterocytes at 22 degrees C or with 2,4-dinitrophenol reduced incorporation of B12 into the E, but not the R-E, component.
     • Key findings · abstract:These results suggest that, using isolated enterocytes, two sequential steps in ileal absorption of B12 can be identified: 1) energy-independent binding of IF-B12 to its receptor on the brush border followed by 2) an energy-dependent event which probably represents transfer of B12 from its receptor into the cell.
     • Relative bioavailability · full text, p.2:ith shaking at approximately 100cycles/min. To measure the total amount of B12 taken up by the enterocytes, duplicate aliquots were removed , diluted 20-fold into resuspension medium at 37•Ž and filtered on 1.2ƒÊm Millipore J. Nutr. Sci. Vitaminol.
     • Relative bioavailability · full text, p.3:esuspension medium. To determine the amount of B12 retained by the enterocytes after treatment with EDTA, duplicate aliquots were removed and diluted 20-fold into a medium consisting of 300mM mannitol, 20mM Hepes (pH 7.4) and 4mM EDTA (mannitol-EDTA). Unless otherwise stated the diluted cells were held at 37•Ž for 5min and filtered, washed with mannitol-EDTA and counted as described above. The amo
     • Relative bioavailability · full text, p.4:re depicted. rate of production of 14CO2was linear for at least 30min. Incubation of ileal cells with 2,4-dinitrophenol (DNP) resulted in a more than 2-fold stimulation of CO2 production while incubation with phlorizin resulted in about 25% inhibition. The time-course for uptake of B12 by isolated ileal and jejunal enterocytes incubated with IF-B12 complex is shown in Fig. 2. Ileal cells took up l
     • Form comparison · full text, p.6:ibitors on B12 uptake by ileal enterocytes. Uptake in the presence of 250ƒÊM DNP, 250ƒÊM DNP without glucose, reduced temperature and 1mM ouabain are compared with a control which was incubated at 37•Ž. R, E and R-E have the same meaning as in the legend to Fig. 4. Values are the mean•}SD for four determinations or the mean for two determinations. incorporation of B12 into each of the above compon
118. Other animalIntrinsic factor-mediated intestinal absorption of cobalamin in the dog.
     Am J Physiol, 1981 · Design: not stated · abstract only (PubMed) · closed/paywalled
     PMID 7315968DOI 10.1152/ajpgi.1981.241.4.G294
     Verification: abstract-only auto-extract; unverified
     • Food effect · abstract:Physicochemical analysis of gastrointestinal fluids and mucosal extracts obtained 3-5 h after cyano[57Co]-cobalamin was fed to dogs demonstrated that 1) all cyano-[57Co]cobalamin became bound to proteins during intraluminal transport; and 2) mucosal cyano[57Co]cobalamin in the extract of the ileal mucosa was bound to intrinsic factor, to intrinsic factor coupled to receptor protein, and to proteins with properties similar to R protein and transcobalamin II.
119. Other animalEffect of bile on vitamin B12 absorption.
     Br Med J, 1980 · Design: stable-isotope · abstract only (PubMed) · open access (bronze)
     PMID 7427470DOI 10.1136/bmj.281.6244.831PMC1714280 (free full text)
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:The standard double-isotope Schilling test was used to study vitamin B12 absorption in seven patients with obstructive jaundice and 10 with T-tube bile duct drainage after cholecystectomy and bile duct exploration.
     • Key findings · abstract:Bile exclusion produced a 50-60% reduction in renal and hepatic uptake of vitamin B12 from the intestinal lumen.
     • Key findings · abstract:These studies suggest that bile plays a part in the normal absorption of vitamin B12.
120. Other animalClinically significant vitamin B12 deficiency secondary to malabsorption of protein-bound vitamin B12.
     Dig Dis Sci, 1979 · Design: not stated · abstract only (PubMed) · closed/paywalled
     PMID 378625DOI 10.1007/BF01297127
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:Protein- (chicken serum) bound [57Co]cyanocobalamin absorption was evaluated in five hypochlorhydric patients who had developed B12 deficiency despite having normal absorption of unbound crystalline vitamin B12.
     • Key findings · abstract:All five patients had decreased urinary excretion of protein-bound B12 (0.06--0.34%) as compared to twelve normal controls (0.61--5.6%), P less than .001.
     • Key findings · abstract:Improvement in protein-bound B12 absorption in four of the five patients occurred with the exogenous administration of hydrochloric acid, pepsin, gastric intrinsic factor, or a combination thereof.
     • Key findings · abstract:This digestive defect is not[excerpt truncated in our database — see source]
121. Other animalAlteration of bile acid metabolism and vitamin-B12-absorption in diabetics on biguanides.
     Diabetologia, 1977 · Design: not stated · abstract only (PubMed) · open access (bronze)
     PMID 873086DOI 10.1007/BF01219698
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:Since vitamin B12malabsorption has been described in diabetics on biguanides and inhibition of bile acid absorption found in rat ileum the effect of treatment with different biguanides (phenformin, buformin, metformin) on bile acid metabolism and vitamin B12 absorption was assessed in maturity onset diabetics.
     • Key findings · abstract:Vitamin B12 malabsorption was most prominent in patients on metformin.
     • Key findings · abstract:Decreased faecal bile acid excretion, positive 14C-glycocholate breath tests, pathological Schilling tests and the reversal of pathological tests by antibiotic treatment suggest that small intestinal bacterial ove[excerpt truncated in our database — see source]
122. In vitroIn situ X-ray absorption spectroelectrochemical study of hydroxocobalamin.
     J Biol Inorg Chem, 2000 · Design: not stated · abstract only (PubMed) · closed/paywalled
     PMID 10819461DOI 10.1007/s007750050360
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:An in situ X-ray absorption spectroscopy (XAS) spectroelectrochemical study of aquocobalamin (system B12a-B12r-B12s) has been carried out in aqueous solutions buffered at different pH values.
123. Species unclearFabrication of vitamin B12-loaded multivesicular liposomes via microfluidic double-emulsification: Extended pharmacokinetics and bioavailability.
     Int J Pharm X, 2026 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
     PMID 42740914DOI 10.1016/j.ijpx.2026.100659PMC13572002 (free full text)
     Verification: full-text auto-extracted verbatim snippets with location; needs human check
     • Key findings · abstract:Pharmacokinetic analysis revealed that compared with free VB12 (mean residence time, MRT = 1.50 h), VB12-MVLs extended MRT to 80.69 h, and VB12-β-MVLs further extended it to 121.42 h, with a relative bioavailability of 191.89%.
     • Relative bioavailability · abstract:Pharmacokinetic analysis revealed that compared with free VB12 (mean residence time, MRT = 1.50 h), VB12-MVLs extended MRT to 80.69 h, and VB12-β-MVLs further extended it to 121.42 h, with a relative bioavailability of 191.89%.
     • Cmax · full text, Section 'Pharmacokinetic study':From the concentration-time curves and kinetic parameters, free VB12 administered subcutaneously was rapidly absorbed (Cmax = 39.26 μg/mL, Tmax = 0.5 h) and quickly eliminated (MRT = 1.50 h).
     • Cmax · full text, Section 'Pharmacokinetic study':In contrast, VB12-MVLs exhibited a clear sustained-release profile with a double-peak phenomenon (Cmax = 1.44 μg/mL, Tmax = 48.0 h), and the MRT was prolonged to 80.69 h, with a relative bioavailability of 97.02% (Fig. 5D-E).
     • Tmax · full text, Section 'Pharmacokinetic study':From the concentration-time curves and kinetic parameters, free VB12 administered subcutaneously was rapidly absorbed (Cmax = 39.26 μg/mL, Tmax = 0.5 h) and quickly eliminated (MRT = 1.50 h).
     • Tmax · full text, Section 'Pharmacokinetic study':In contrast, VB12-MVLs exhibited a clear sustained-release profile with a double-peak phenomenon (Cmax = 1.44 μg/mL, Tmax = 48.0 h), and the MRT was prolonged to 80.69 h, with a relative bioavailability of 97.02% (Fig. 5D-E).
     • Tmax · full text, Section 'Pharmacokinetic study':Compared with VB12-MVLs, VB12-β-MVLs had a Tmax of 60.5 h, an MRT further prolonged to 121.42 h, an AUC0-t increased to 119.72 h·μg/mL, and a relative bioavailability of 191.89%, approximately twice that of VB12-MVLs.
     • AUC · full text, Section 'Pharmacokinetic study':Compared with VB12-MVLs, VB12-β-MVLs had a Tmax of 60.5 h, an MRT further prolonged to 121.42 h, an AUC0-t increased to 119.72 h·μg/mL, and a relative bioavailability of 191.89%, approximately twice that of VB12-MVLs.
     • Relative bioavailability · full text, Section 'Pharmacokinetic study':In contrast, VB12-MVLs exhibited a clear sustained-release profile with a double-peak phenomenon (Cmax = 1.44 μg/mL, Tmax = 48.0 h), and the MRT was prolonged to 80.69 h, with a relative bioavailability of 97.02% (Fig. 5D-E).
     • Relative bioavailability · full text, Section 'Pharmacokinetic study':Compared with VB12-MVLs, VB12-β-MVLs had a Tmax of 60.5 h, an MRT further prolonged to 121.42 h, an AUC0-t increased to 119.72 h·μg/mL, and a relative bioavailability of 191.89%, approximately twice that of VB12-MVLs.
     • Form comparison · full text, Section 'Pharmacokinetic study':Compared with VB12-MVLs, VB12-β-MVLs had a Tmax of 60.5 h, an MRT further prolonged to 121.42 h, an AUC0-t increased to 119.72 h·μg/mL, and a relative bioavailability of 191.89%, approximately twice that of VB12-MVLs.
     • Form comparison · full text, Section 'Safety evaluation':The results showed that, compared with the positive control (1% Triton X-100) which caused complete hemolysis (Fig. 6B), VB12-MVLs at concentrations as high as 4 mg mL−1 showed no obvious hemolysis after incubation with 2% RBC suspension for 3 h, demonstrating good hemocompatibility of VB12-MVLs.
124. Species unclearThe uptake of ingested vitamin B12 and its total body balance: a mathematical model suggests the optimal supplementation strategy.
     Biochimie, 2025 · Design: not stated · abstract only (PubMed) · open access (hybrid)
     PMID 41360297DOI 10.1016/j.biochi.2025.12.002
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:Impaired or insufficient uptake of vitamin B12 causes neurological disorders, anemia, and various diffuse symptoms, all historically called pernicious anemia (PA).
     • Key findings · abstract:The current work suggests physiologically realistic algebraic equations to express the changes in B via the daily B12-uptake.
     • Key findings · abstract:The modeled values of B showed that the daily ingestion of B12 = 3 × 2.0 μg maintains the steady state value of B = 1316/1858/2683 μg in healthy individuals with low/mean/high types of B12-uptake.
     • Key findings · abstract:The "classical" PA-patients have a highly decreased intrinsic factor (falling from 30 μg of B12-equivalents[excerpt truncated in our database — see source]
125. Species unclearStructural Evolution of Photoexcited Methylcobalamin toward a CarH-like Metastable State: Evidence from Time-Resolved X-ray Absorption and X-ray Emission.
     J Phys Chem B, 2024 · Design: not stated · abstract (PubMed); full-text PDF saved · open access (green)
     PMID 39150518DOI 10.1021/acs.jpcb.4c03729PDF
     Verification: full-text auto-extracted verbatim snippets with location; needs human check
     • Form comparison · full text, p.24:24 approximate break between the pre-edge and XANES regions. (a) The difference spectrum and estimated excited state spectrum at ~100 fs compared with the simulated results using ground state axial bond lengths and an expanded ring 50% of the distance between the ground state ring and the Rbl ring. (b) The difference spectrum and estimated excited state spectrum at ~300 fs compared with the simula
     • Form comparison · full text, p.32:tion of AdoCbl in water are distinctly different from those seen in either CarH or MeCbl. The evolution of the optical spectrum of AdoCbl in water is compared with MeCbl in Figure 5. In contrast to the modest changes observed for MeCbl and for AdoCbl bound to CarH, significant evolution is observed for AdoCbl. Here the X-ray measurements on MeCbl may provide some additional insight. The changes in
126. Species unclearA cobalt concentration sensitive Btu-like system facilitates cobalamin uptake in Anabaena sp. PCC 7120.
     Microb Cell, 2024 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
     PMID 38379927DOI 10.15698/mic2024.02.814PMC10878165 (free full text)
     Verification: full text read; no PK numbers matched
     • Key findings · abstract:BtuB2 is important for fast uptake of cobalamin under conditions with low external cobalt, whereas BtuB1 appears to function in cobalamin uptake under conditions of sufficient cobalt supply.
     • Key findings · abstract:The uptake of cobalamin depends further on the TonB and a BtuFCD machinery, as mutants of tonB3 and btuD show reduced cobalamin uptake rates.
127. Species unclearDirect Structural and Chemical Characterization of the Photolytic Intermediates of Methylcobalamin Using Time-Resolved X-ray Absorption Spectroscopy.
     J Phys Chem Lett, 2018 · Design: not stated · abstract (PubMed); full-text PDF saved · open access (green)
     PMID 29510052DOI 10.1021/acs.jpclett.8b00083PDF
     Verification: full text read; no PK numbers matched
128. Species unclearRoute and Type of Formulation Administered Influences the Absorption and Disposition of Vitamin B12 Levels in Serum.
     J Funct Biomater, 2018 · Design: not stated · n: 16 subjects · full text (Europe PMC XML) + abstract · open access (gold)
     PMID 29361736DOI 10.3390/jfb9010012PMC5872098 (free full text)
     Verification: full-text auto-extracted verbatim snippets with location; needs human check
     • Key findings · abstract:A nanoparticle delivered vitamin B12 through a NanoCelle platform was observed to be significantly (p < 0.05) better absorbed than all other dose equivalent platforms (i.e., tablets, emulsions, or liposomes) from baseline to 1, 3, and 6 h of the study period.
     • Key findings · abstract:The nanoparticle platform delivered vitamin B12 demonstrated an enhanced and significant absorption profile as exemplified by rapid systemic detection (i.e., 1 h from baseline) when administered to the oro-buccal mucosa with no reports of any adverse events of toxicity.
     • Key findings · abstract:The nanoparticle formulation of methylcobalamin (1000 µg/dose in[excerpt truncated in our database — see source]
     • Fractional absorption · abstract:A nanoparticle delivered vitamin B12 through a NanoCelle platform was observed to be significantly (p < 0.05) better absorbed than all other dose equivalent platforms (i.e., tablets, emulsions, or liposomes) from baseline to 1, 3, and 6 h of the study period.
     • Form comparison · full text, Section '3. Results':Furthermore, there was a significantly increased serum levels of vitamin B12 from baseline to 1 and 3 h for only the nanoparticle delivered platform when compared to all other by equivalent dose formulations administered irrespective of mode of delivery (i.e., emulsion, tablet or liposome) (Table 2).
129. Species unclearVITAMIN B12 LEVELS IN PATIENTS WITH TYPE 2 DIABETES MELLITUS ON METFORMIN.
     Ann Ib Postgrad Med, 2015 · Design: not stated · full text (Europe PMC XML) + abstract · open access (PMC)
     PMID 27162518PMC4853879 (free full text)
     Verification: full-text auto-extracted verbatim snippets with location; needs human check
     • Key findings · abstract:OBJECTIVE: This study was carried out to determine the serum level of vitamin B12 in Nigerian patients with type 2 diabetes mellitus (T2DM) on metformin.
     • Key findings · abstract:METHODS: Serum vitamin B12 level was determined using high performance liquid chromatography (HPLC) in 81 T2DM patients who have been on metformin for 5 years or more.
     • Key findings · abstract:Vitamin B12 deficiency was defined as serum concentration of <200 pg/dl, borderline deficiency as 200 - 300 pg/dl and >300 pg/dl as normal.
     • Key findings · abstract:CONCLUSION: Low serum vitamin B12 level is associated with longer duration and higher dose of metformin use.
     • Form comparison · full text, Section 'RESULTS':It was observed that the median level of vitamin B12 was significantly lower in patients who were on metformin at a dose of >1000 mg/ day compared with patients who were on metformin at a dose of ≤1000 mg/day.
     • Form comparison · full text, Section 'RESULTS':In contrast, the mean body weight and BMI were significantly higher in patients who were on metformin at a dose of ≤1000 mg/day compared with patients who were on metformin at a dose of <1000 mg/day (Table 2).
130. Species unclearEffect of administration route on the pharmacokinetics of cobalamin in elderly patients: a randomized controlled trial.
     Curr Ther Res Clin Exp, 2014 · Design: not stated · full text (Europe PMC XML) + abstract · open access (gold)
     PMID 25031664DOI 10.1016/j.curtheres.2014.01.001PMC3994916 (free full text)
     Verification: full-text auto-extracted verbatim snippets with location; needs human check
     • Key findings · abstract:Inclusion criteria were written informed consent, age >65 years, and a cobalamin serum concentration <200 pmol/L.
     • Key findings · abstract:Total cobalamin serum concentrations were determined 10 times within 48 hours after administration.
     • Key findings · abstract:The differences in Cmax, Tmax, and AUC0-48 h per administration route were statistically compared using ANOVA.
     • Key findings · abstract:RESULTS: The average Cmax was 1 nmol/L after intranasal and 38.5 nmol/L after intramuscular administration.
     • Key findings · abstract:The average Tmax for intranasal and intramuscular administration was 42 minutes versus 342 minutes, respectively, and the AUC0-48 h was 1.3 µmol/L/min versus 4[excerpt truncated in our database — see source]
     • Cmax · abstract:The differences in Cmax, Tmax, and AUC0-48 h per administration route were statistically compared using ANOVA.
     • Cmax · abstract:RESULTS: The average Cmax was 1 nmol/L after intranasal and 38.5 nmol/L after intramuscular administration.
     • Tmax · abstract:The differences in Cmax, Tmax, and AUC0-48 h per administration route were statistically compared using ANOVA.
     • Tmax · abstract:The average Tmax for intranasal and intramuscular administration was 42 minutes versus 342 minutes, respectively, and the AUC0-48 h was 1.3 µmol/L/min versus 45.4 µmol/L/min, respectively.
     • AUC · abstract:The differences in Cmax, Tmax, and AUC0-48 h per administration route were statistically compared using ANOVA.
     • AUC · abstract:The average Tmax for intranasal and intramuscular administration was 42 minutes versus 342 minutes, respectively, and the AUC0-48 h was 1.3 µmol/L/min versus 45.4 µmol/L/min, respectively.
     • Cmax · full text, Section 'Results':The Cmax varied between 0.5 and 2 nmol/L and the time to maximum concentration was comparable among the patients with minor differences in Tmax.
     • Cmax · full text, Section 'Results':After intranasal administration a significantly (P < 0.05) lower Cmax (ie, 1 vs 38.5 nmol/L) was determined compared with intramuscular administration.
     • Tmax · full text, Section 'Results':The Cmax varied between 0.5 and 2 nmol/L and the time to maximum concentration was comparable among the patients with minor differences in Tmax.
     • Tmax · full text, Section 'Results':Contrary to the intranasal administration group, the Tmax varied considerably among these patients, ranging between 60 and 480 minutes.
     • Tmax · full text, Section 'Results':Cobalamin absorption was significantly (P < 0.05) faster following intranasal administration (ie, Tmax 42 vs 324 minutes, respectively).
     • AUC · full text, Section 'Results':The AUC0-48 h among patients varied between 0.67 and 2 μmol/L/min.
     • AUC · full text, Section 'Results':Patients in this group had AUC0-48 h that varied noticeably between 8.7 and 76 μmol/L/min.
     • AUC · full text, Section 'Results':AUC0-48 h was significantly (P < 0.05) smaller after intranasal compared with intramuscular administration.
     • Form comparison · full text, Section 'Results':After intranasal administration a significantly (P < 0.05) lower Cmax (ie, 1 vs 38.5 nmol/L) was determined compared with intramuscular administration.
     • Form comparison · full text, Section 'Results':Cobalamin absorption was significantly (P < 0.05) faster following intranasal administration (ie, Tmax 42 vs 324 minutes, respectively).
     • Form comparison · full text, Section 'Results':The bioavailability of cobalamin after intranasal administration was estimated to be 2% compared with intramuscular administration.
131. Species unclearExcited state electron transfer after visible light absorption by the Co(I) state of vitamin B12.
     Chem Commun (Camb), 2014 · Design: not stated · abstract only (PubMed) · closed/paywalled
     PMID 25232558DOI 10.1039/c4cc02221a
     Verification: abstract-only auto-extract; unverified
132. Species unclearUptake and physiological function of vitamin B12 in a photosynthetic unicellular coccolithophorid alga, Pleurochrysis carterae.
     Biosci Biotechnol Biochem, 2002 · Design: not stated · abstract only (PubMed) · open access (bronze)
     PMID 11866107DOI 10.1271/bbb.66.195
     Verification: abstract-only auto-extract; unverified
133. Species unclearVitamin B12 bioavailability from egg yolk and egg white: relationship to binding proteins.
     Am J Clin Nutr, 1983 · Design: not stated · abstract only (PubMed) · closed/paywalled
     PMID 6684393DOI 10.1093/ajcn/38.3.436
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:Egg yolk has been reported to inhibit B12 absorption less than egg white suggesting that different vitamin B12 binding proteins may be present in egg white and egg yolk.
     • Key findings · abstract:These studies suggest that egg yolk and egg white contain distinct R binders which could explain the differential B12 absorption from egg yolk and egg white.
134. Species unclearVitamin B12 uptake by intestinal microorganisms: mechanism and relevance to syndromes of intestinal bacterial overgrowth.
     J Clin Invest, 1971 · Design: not stated · abstract only (PubMed) · open access (bronze)
     PMID 4994753DOI 10.1172/JCI106581PMC292032 (free full text)
     Verification: abstract-only auto-extract; unverified
     • Key findings · abstract:The mechanism of bacterial uptake of vitamin B(12), the spectrum of microorganisms capable of such uptake, and the factors involved were the subject of this study.
     • Key findings · abstract:Bacterial uptake of vitamin B(12) was found to be at least a two stage process.
     • Key findings · abstract:A primary uptake phase which was rapid (1 min or less), pH dependent, nontemperature dependent, did not require viable organisms and was insensitive to either the metabolic inhibitor dinitrophenol or to the sulfhydryl inhibitor N-ethyl-maleimide.
     • Key findings · abstract:Protein denaturation (formalin treatment or autoclaving) abolished all B(12) uptake.
     • Key findings · abstract:Although differe[excerpt truncated in our database — see source]