Component

B12 deficiency diagnosis

Clinical classification with assay and case definitions retained; not a direct serum concentration or one molecular lesion.

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. At least two years of H2-antagonist supply without PPI exposure was associated with a B12-deficiency diagnosis (OR 1.25; 95% CI 1.17–1.34).

    Histamine H2 receptor antagonist drug class → B12 deficiency diagnosis source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    Case-control study: 25956 incident B12-deficiency diagnoses and 184199 controls in Kaiser Permanente Northern California.
    exposure
    Prescription records for at least two years of PPI or H2-antagonist exposure; no randomized acid suppression.
    limitations
    Not an independent cohort or a randomized comparison between drug classes; diagnosis is not the same endpoint as measured mean serum concentration.
    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 second acid-suppressing drug class showed an association in the same study.
    primary_references
    [b12-lam2013] Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency (2013). https://pubmed.ncbi.nlm.nih.gov/24327038/ DOI: 10.1001/jama.2013.280490
    tissue_or_cell_type
    Human blood or whole-person endpoints

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1673–1683

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Case-control study: 25956 incident B12-deficiency diagnoses and 184199 controls in Kaiser Permanente Northern California. · source_derived_draft · unverified_draft

    ### b12-acid-suppression-h2-association At least two years of H2-antagonist supply without PPI exposure was associated with a B12-deficiency diagnosis (OR 1.25; 95% CI 1.17–1.34). Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: A second acid-suppressing drug class showed an association in the same study. organism: Homo sapiens tissue_or_cell_type: Human blood or whole-person endpoints experimental_model: Case-control study: 25956 incident B12-deficiency diagnoses and 184199 controls in Kaiser Permanente Northern California. limitations: Not an independent cohort or a randomized comparison between drug classes; diagnosis is not the same endpoint as measured mean serum concentration. exposure: Prescription records for at least two years of PPI or H2-antagonist exposure; no randomized acid suppression. [b12-lam2013] Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency (2013). https://pubmed.ncbi.nlm.nih.gov/24327038/ DOI: 10.1001/jama.2013.280490
    Complete structured claim and evidence

  2. At least two years of PPI supply was associated with a B12-deficiency diagnosis (OR 1.65; 95% CI 1.58–1.73).

    Proton pump inhibitor drug class → B12 deficiency diagnosis source_derived_draftungraded
    Experimental context and source evidence
    experimental_model
    Case-control study: 25956 incident B12-deficiency diagnoses and 184199 controls in Kaiser Permanente Northern California.
    exposure
    Prescription records for at least two years of PPI or H2-antagonist exposure; no randomized acid suppression.
    limitations
    Prescription/diagnosis case-control data; no direct gastric pH or absorption measurement, and residual confounding remains.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    Long-term acid-suppressing prescriptions were associated with more diagnosed B12 deficiency.
    primary_references
    [b12-lam2013] Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency (2013). https://pubmed.ncbi.nlm.nih.gov/24327038/ DOI: 10.1001/jama.2013.280490
    tissue_or_cell_type
    Human blood or whole-person endpoints

    Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1661–1671

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Case-control study: 25956 incident B12-deficiency diagnoses and 184199 controls in Kaiser Permanente Northern California. · source_derived_draft · unverified_draft

    ### b12-acid-suppression-ppi-association At least two years of PPI supply was associated with a B12-deficiency diagnosis (OR 1.65; 95% CI 1.58–1.73). Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Long-term acid-suppressing prescriptions were associated with more diagnosed B12 deficiency. organism: Homo sapiens tissue_or_cell_type: Human blood or whole-person endpoints experimental_model: Case-control study: 25956 incident B12-deficiency diagnoses and 184199 controls in Kaiser Permanente Northern California. limitations: Prescription/diagnosis case-control data; no direct gastric pH or absorption measurement, and residual confounding remains. exposure: Prescription records for at least two years of PPI or H2-antagonist exposure; no randomized acid suppression. [b12-lam2013] Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency (2013). https://pubmed.ncbi.nlm.nih.gov/24327038/ DOI: 10.1001/jama.2013.280490
    Complete structured claim and evidence

  3. MMA was elevated in 12.2% of the folate-deficient group; all but one were attributed to renal insufficiency or hypovolemia.

    Methylmalonic acid → B12 deficiency diagnosis source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    cross_nutrient
    Separates a shared diagnostic setting from direct cofactor identity.
    experimental_model
    Selected clear-cut deficiency series: 434 B12 episodes in 406 patients and 123 folate episodes in 119 patients.
    exposure
    Serum MMA and total homocysteine assays; elevation defined above three standard deviations of the reference mean.
    limitations
    These are authors’ clinical attributions, not randomized tests of renal causation. Folate does not thereby become the MMUT cofactor.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    An abnormal MMA result needs its clinical and kidney context.
    primary_references
    [b12-savage1994] Sensitivity of serum methylmalonic acid and total homocysteine determinations for diagnosing cobalamin and folate deficiencies (1994). https://pubmed.ncbi.nlm.nih.gov/8154512/ DOI: 10.1016/0002-9343(94)90149-x
    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 1487–1498

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Selected clear-cut deficiency series: 434 B12 episodes in 406 patients and 123 folate episodes in 119 patients. · source_derived_draft · unverified_draft

    ### b12-mma-folate-renal-confounding MMA was elevated in 12.2% of the folate-deficient group; all but one were attributed to renal insufficiency or hypovolemia. Condition category: biomarker_context nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: An abnormal MMA result needs its clinical and kidney context. organism: Homo sapiens tissue_or_cell_type: Human blood or whole-person endpoints experimental_model: Selected clear-cut deficiency series: 434 B12 episodes in 406 patients and 123 folate episodes in 119 patients. limitations: These are authors’ clinical attributions, not randomized tests of renal causation. Folate does not thereby become the MMUT cofactor. exposure: Serum MMA and total homocysteine assays; elevation defined above three standard deviations of the reference mean. cross_nutrient: Separates a shared diagnostic setting from direct cofactor identity. [b12-savage1994] Sensitivity of serum methylmalonic acid and total homocysteine determinations for diagnosing cobalamin and folate deficiencies (1994). https://pubmed.ncbi.nlm.nih.gov/8154512/ DOI: 10.1016/0002-9343(94)90149-x
    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