Component

Circulating holotranscobalamin concentration

Independent substance, clinical endpoint or measured readout; study context is retained with each finding.

3 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

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.

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.

Recorded relationships

What acts on it

  1. Oral calcium supplementation reversed the metformin-induced depression of serum holotranscobalamin.

    Oral calcium supplementation in the 2000 study → Circulating holotranscobalamin concentration source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/metformin-research/10977010.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b", "start_char": 0, "end_char": 1267, "text_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b"}
    experimental_model
    Comparative study in 21 people with type 2 diabetes, 14 switched to metformin, with oral calcium supplementation
    exposure
    Metformin for three months, then oral calcium supplementation
    limitations
    A small, non-randomised comparative study. The calcium-dependent ileal mechanism is the authors’ interpretation of the reversal, not a direct measurement of receptor binding.
    nutrient_topic
    Metformin research collection; topical membership is not evidence of a direct clinical effect, and pharmacological exposure is not dietary intake. · Metformin
    organism
    Human
    plain_language
    Adding calcium undid the drug’s effect on the vitamin.
    primary_references
    [metformin-p10977010] Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. (2000). https://pubmed.ncbi.nlm.nih.gov/10977010/ DOI: 10.2337/diacare.23.9.1227
    tissue_or_cell_type
    Ileal absorption
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Metformin: transport, molecular targets, gut mechanisms and nutrient interactions (2026-09-19) · lines 1139–1150

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Comparative study in 21 people with type 2 diabetes, 14 switched to metformin, with oral calcium supplementation · source_derived_draft · unverified_draft

    ### metformin-b12-calcium-reversal Oral calcium supplementation reversed the metformin-induced depression of serum holotranscobalamin. Condition category: nutrient_deficiency nutrient_topic: Metformin research collection; topical membership is not evidence of a direct clinical effect, and pharmacological exposure is not dietary intake. plain_language: Adding calcium undid the drug’s effect on the vitamin. organism: Human tissue_or_cell_type: Ileal absorption experimental_model: Comparative study in 21 people with type 2 diabetes, 14 switched to metformin, with oral calcium supplementation limitations: A small, non-randomised comparative study. The calcium-dependent ileal mechanism is the authors’ interpretation of the reversal, not a direct measurement of receptor binding. exposure: Metformin for three months, then oral calcium supplementation evidence_span: {"source_cache": "artifacts/metformin-research/10977010.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b", "start_char": 0, "end_char": 1267, "text_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b"} [metformin-p10977010] Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. (2000). https://pubmed.ncbi.nlm.nih.gov/10977010/ DOI: 10.2337/diacare.23.9.1227
    Complete structured claim and evidence

  2. Serial measurements showed a similar decline in serum total vitamin B12 and in holotranscobalamin during metformin therapy.

    Metformin → Circulating holotranscobalamin concentration source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/metformin-research/10977010.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b", "start_char": 0, "end_char": 1267, "text_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b"}
    experimental_model
    Comparative study in 21 people with type 2 diabetes, 14 switched to metformin, with oral calcium supplementation
    exposure
    Metformin for three months, then oral calcium supplementation
    limitations
    A small, non-randomised comparative study. The calcium-dependent ileal mechanism is the authors’ interpretation of the reversal, not a direct measurement of receptor binding.
    nutrient_topic
    Metformin research collection; topical membership is not evidence of a direct clinical effect, and pharmacological exposure is not dietary intake. · Metformin
    organism
    Human
    plain_language
    The carrier-bound fraction that reaches cells fell alongside the total.
    primary_references
    [metformin-p10977010] Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. (2000). https://pubmed.ncbi.nlm.nih.gov/10977010/ DOI: 10.2337/diacare.23.9.1227
    tissue_or_cell_type
    Ileal absorption
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Metformin: transport, molecular targets, gut mechanisms and nutrient interactions (2026-09-19) · lines 1126–1137

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Comparative study in 21 people with type 2 diabetes, 14 switched to metformin, with oral calcium supplementation · source_derived_draft · unverified_draft

    ### metformin-b12-holotc-decline Serial measurements showed a similar decline in serum total vitamin B12 and in holotranscobalamin during metformin therapy. Condition category: nutrient_deficiency nutrient_topic: Metformin research collection; topical membership is not evidence of a direct clinical effect, and pharmacological exposure is not dietary intake. plain_language: The carrier-bound fraction that reaches cells fell alongside the total. organism: Human tissue_or_cell_type: Ileal absorption experimental_model: Comparative study in 21 people with type 2 diabetes, 14 switched to metformin, with oral calcium supplementation limitations: A small, non-randomised comparative study. The calcium-dependent ileal mechanism is the authors’ interpretation of the reversal, not a direct measurement of receptor binding. exposure: Metformin for three months, then oral calcium supplementation evidence_span: {"source_cache": "artifacts/metformin-research/10977010.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b", "start_char": 0, "end_char": 1267, "text_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b"} [metformin-p10977010] Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. (2000). https://pubmed.ncbi.nlm.nih.gov/10977010/ DOI: 10.2337/diacare.23.9.1227
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Cyanocobalamin increased serum B12 and holotranscobalamin and reduced total homocysteine during the 12-month trial.

    Cyanocobalamin → Serum cobalamin concentration source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    experimental_model
    Double-blind randomized trial: 201 adults aged at least 75 with B12 107–210 pmol/L, without anemia or relevant neurologic/cognitive signs; 191 had outcome assessment.
    exposure
    Oral cyanocobalamin 1 mg/day versus placebo for 12 months.
    limitations
    Blood responses do not establish delivery or functional recovery in every tissue.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    The tablets changed the biochemical measurements.
    primary_references
    [b12-dangour2015] Effects of vitamin B-12 supplementation on neurologic and cognitive function in older people: a randomized controlled trial (2015). https://pubmed.ncbi.nlm.nih.gov/26135351/ DOI: 10.3945/ajcn.115.110775
    tissue_or_cell_type
    Human blood or whole-person endpoints
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1512–1522

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind randomized trial: 201 adults aged at least 75 with B12 107–210 pmol/L, without anemia or relevant neurologic/cognitive signs; 191 had outcome assessment. · source_derived_draft · unverified_draft

    ### b12-dangour-status-response Cyanocobalamin increased serum B12 and holotranscobalamin and reduced total homocysteine during the 12-month trial. Condition category: biomarker_context nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: The tablets changed the biochemical measurements. organism: Homo sapiens tissue_or_cell_type: Human blood or whole-person endpoints experimental_model: Double-blind randomized trial: 201 adults aged at least 75 with B12 107–210 pmol/L, without anemia or relevant neurologic/cognitive signs; 191 had outcome assessment. limitations: Blood responses do not establish delivery or functional recovery in every tissue. exposure: Oral cyanocobalamin 1 mg/day versus placebo for 12 months. [b12-dangour2015] Effects of vitamin B-12 supplementation on neurologic and cognitive function in older people: a randomized controlled trial (2015). https://pubmed.ncbi.nlm.nih.gov/26135351/ DOI: 10.3945/ajcn.115.110775
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

    Evidence, AI assistance and curation standards