Component
Carbon-13-labeled cyanocobalamin tracer
Stable-isotope cyanocobalamin probe used in the 2024 bioavailability study; distinct from unlabeled cyanocobalamin.
2 recorded relationships. Experimental role, claim status and evidence remain attached to each record.
How nutrients influence it
Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.
Other things that act on it
Enzymes, hormones, genes, and other components with a recorded effect. These are not nutrients, so they do not count toward the arrows above. Each finding names the chapter that recorded it.
How nutrients reach it in more than one step
Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.
Tracing routes…
What it does
Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.
Where it participates (unsigned role)
Adding calcium 500 mg to metformin 850 mg raised mean tracer bioavailability from 30.8% to 46.4% in seven healthy completers (p=0.003).
Experimental context and source evidence
- cross_nutrient
- true
- experimental_model
- Seven healthy adult completers; three experimental days separated by one-month washouts
- exposure
- Metformin 850 mg plus calcium 500 mg and carbon-13 cyanocobalamin
- limitations
- Small acute tracer pilot in healthy adults; cannot establish prevention of chronic deficiency or identify the exact molecular metformin target. Doses describe the experiment, not advice.
- nutrient_topic
- Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
- organism
- Homo sapiens
- plain_language
- Calcium coadministration reversed the tracer reduction in this pilot.
- primary_references
- [muralidharan-2024-calcium] Effect of calcium supplementation on reversing metformin-based inhibition of vitamin B12 bioavailability in healthy adults using a [13C] cyanocobalamin tracer - A pilot study. (2024). https://pubmed.ncbi.nlm.nih.gov/38901951/ DOI: 10.1016/j.clnesp.2024.04.024
- tissue_or_cell_type
- Intestinal absorption assessed from serial venous tracer measurements
Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 465–476
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Seven healthy adult completers; three experimental days separated by one-month washouts · source_derived_draft · unverified_draft
### b12-abs-calcium-tracer-rescue Adding calcium 500 mg to metformin 850 mg raised mean tracer bioavailability from 30.8% to 46.4% in seven healthy completers (p=0.003). Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Calcium coadministration reversed the tracer reduction in this pilot. organism: Homo sapiens tissue_or_cell_type: Intestinal absorption assessed from serial venous tracer measurements experimental_model: Seven healthy adult completers; three experimental days separated by one-month washouts limitations: Small acute tracer pilot in healthy adults; cannot establish prevention of chronic deficiency or identify the exact molecular metformin target. Doses describe the experiment, not advice. exposure: Metformin 850 mg plus calcium 500 mg and carbon-13 cyanocobalamin cross_nutrient: true [muralidharan-2024-calcium] Effect of calcium supplementation on reversing metformin-based inhibition of vitamin B12 bioavailability in healthy adults using a [13C] cyanocobalamin tracer - A pilot study. (2024). https://pubmed.ncbi.nlm.nih.gov/38901951/ DOI: 10.1016/j.clnesp.2024.04.024
Complete structured claim and evidenceIn seven healthy completers, tracer bioavailability averaged 30.8% with metformin 850 mg versus 42.6% on the control day (paired comparison p=0.010).
Experimental context and source evidence
- cross_nutrient
- false
- experimental_model
- Seven healthy adult completers; three experimental days separated by one-month washouts
- exposure
- Oral carbon-13 cyanocobalamin with metformin 850 mg versus tracer alone
- limitations
- Small acute tracer pilot in healthy adults; cannot establish prevention of chronic deficiency or identify the exact molecular metformin target. Doses describe the experiment, not advice.
- nutrient_topic
- Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
- organism
- Homo sapiens
- plain_language
- A single metformin exposure lowered measured B12 tracer availability.
- primary_references
- [muralidharan-2024-calcium] Effect of calcium supplementation on reversing metformin-based inhibition of vitamin B12 bioavailability in healthy adults using a [13C] cyanocobalamin tracer - A pilot study. (2024). https://pubmed.ncbi.nlm.nih.gov/38901951/ DOI: 10.1016/j.clnesp.2024.04.024
- tissue_or_cell_type
- Intestinal absorption assessed from serial venous tracer measurements
Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 452–463
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Seven healthy adult completers; three experimental days separated by one-month washouts · source_derived_draft · unverified_draft
### b12-abs-metformin-tracer In seven healthy completers, tracer bioavailability averaged 30.8% with metformin 850 mg versus 42.6% on the control day (paired comparison p=0.010). Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: A single metformin exposure lowered measured B12 tracer availability. organism: Homo sapiens tissue_or_cell_type: Intestinal absorption assessed from serial venous tracer measurements experimental_model: Seven healthy adult completers; three experimental days separated by one-month washouts limitations: Small acute tracer pilot in healthy adults; cannot establish prevention of chronic deficiency or identify the exact molecular metformin target. Doses describe the experiment, not advice. exposure: Oral carbon-13 cyanocobalamin with metformin 850 mg versus tracer alone cross_nutrient: false [muralidharan-2024-calcium] Effect of calcium supplementation on reversing metformin-based inhibition of vitamin B12 bioavailability in healthy adults using a [13C] cyanocobalamin tracer - A pilot study. (2024). https://pubmed.ncbi.nlm.nih.gov/38901951/ DOI: 10.1016/j.clnesp.2024.04.024
Complete structured claim and evidence
The events it takes part in
A mechanism often involves more than two components. These are the full events, with every participant and its role.
Situations it appears in
Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.
In the sources
Preserved passages that mention this component, quoted exactly. Open one to read it in context.
Open hypotheses
Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.
This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.