Component

Neuropsychological test performance

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. No cognitive benefit accompanied B12 alone or B12 plus folic acid over 24 weeks; memory improvement was greater with placebo than B12 alone (P=0.0036).

    Cyanocobalamin → Neuropsychological test performance source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    experimental_model
    Double-blind randomized trial: 195 adults aged at least 70 with mild B12 deficiency.
    exposure
    Cyanocobalamin 1000 micrograms/day, cyanocobalamin 1000 micrograms plus folic acid 400 micrograms/day, or placebo for 24 weeks.
    limitations
    Several tested domains and a short trial; the memory comparison does not prove generalized neurotoxicity.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    Correcting the biochemical shortage was not a general cognitive enhancer in this trial.
    primary_references
    [b12-eussen2006] Effect of oral vitamin B-12 with or without folic acid on cognitive function in older people with mild vitamin B-12 deficiency: a randomized, placebo-controlled trial (2006). https://pubmed.ncbi.nlm.nih.gov/16895884/ DOI: 10.1093/ajcn/84.2.361
    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 1549–1559

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind randomized trial: 195 adults aged at least 70 with mild B12 deficiency. · source_derived_draft · unverified_draft

    ### b12-eussen-cognition-boundary No cognitive benefit accompanied B12 alone or B12 plus folic acid over 24 weeks; memory improvement was greater with placebo than B12 alone (P=0.0036). Condition category: biomarker_context nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Correcting the biochemical shortage was not a general cognitive enhancer in this trial. organism: Homo sapiens tissue_or_cell_type: Human blood or whole-person endpoints experimental_model: Double-blind randomized trial: 195 adults aged at least 70 with mild B12 deficiency. limitations: Several tested domains and a short trial; the memory comparison does not prove generalized neurotoxicity. exposure: Cyanocobalamin 1000 micrograms/day, cyanocobalamin 1000 micrograms plus folic acid 400 micrograms/day, or placebo for 24 weeks. [b12-eussen2006] Effect of oral vitamin B-12 with or without folic acid on cognitive function in older people with mild vitamin B-12 deficiency: a randomized, placebo-controlled trial (2006). https://pubmed.ncbi.nlm.nih.gov/16895884/ DOI: 10.1093/ajcn/84.2.361
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. The primary posterior tibial CMAP endpoint showed a mean difference of -0.2 mV (95% CI -0.8 to 0.3); secondary nerve-conduction and cognitive outcomes also showed no significant benefit.

    Cyanocobalamin → Posterior tibial compound muscle action potential amplitude 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
    Null results have confidence limits; do not extrapolate to symptomatic deficiency.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    Improved B12-related markers did not translate into measured neurologic or cognitive improvement in this asymptomatic group.
    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 1524–1534

    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-neural-null The primary posterior tibial CMAP endpoint showed a mean difference of -0.2 mV (95% CI -0.8 to 0.3); secondary nerve-conduction and cognitive outcomes also showed no significant benefit. Condition category: biomarker_context nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Improved B12-related markers did not translate into measured neurologic or cognitive improvement in this asymptomatic group. 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: Null results have confidence limits; do not extrapolate to symptomatic deficiency. 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

  2. At 27 months, groups did not differ significantly in change in Clinical Dementia Rating or neuropsychological test z-scores.

    Methylcobalamin → Clinical Dementia Rating score source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    experimental_model
    Randomized placebo-controlled trial: 271 nondemented diabetic outpatients aged at least 70, plasma B12 150–300 pmol/L.
    exposure
    Oral methylcobalamin 1000 micrograms/day versus placebo for 27 months.
    limitations
    More smokers were randomized to active treatment; excluding smokers did not change the reported result.
    nutrient_topic
    Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
    organism
    Homo sapiens
    plain_language
    Better markers did not establish protection from cognitive decline in this group.
    primary_references
    [b12-kwok2017] A randomized placebo controlled trial of vitamin B12 supplementation to prevent cognitive decline in older diabetic people with borderline low serum vitamin B12 (2017). https://pubmed.ncbi.nlm.nih.gov/27823800/ DOI: 10.1016/j.clnu.2016.10.018
    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 1573–1583

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized placebo-controlled trial: 271 nondemented diabetic outpatients aged at least 70, plasma B12 150–300 pmol/L. · source_derived_draft · unverified_draft

    ### b12-methylcobalamin-diabetes-cognition At 27 months, groups did not differ significantly in change in Clinical Dementia Rating or neuropsychological test z-scores. Condition category: biomarker_context nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Better markers did not establish protection from cognitive decline in this group. organism: Homo sapiens tissue_or_cell_type: Human blood or whole-person endpoints experimental_model: Randomized placebo-controlled trial: 271 nondemented diabetic outpatients aged at least 70, plasma B12 150–300 pmol/L. limitations: More smokers were randomized to active treatment; excluding smokers did not change the reported result. exposure: Oral methylcobalamin 1000 micrograms/day versus placebo for 27 months. [b12-kwok2017] A randomized placebo controlled trial of vitamin B12 supplementation to prevent cognitive decline in older diabetic people with borderline low serum vitamin B12 (2017). https://pubmed.ncbi.nlm.nih.gov/27823800/ DOI: 10.1016/j.clnu.2016.10.018
    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