Key findings from detailed records
Population: 201 adults aged 75 or older with moderate B12 deficiency but no anemia or neurological or cognitive symptoms. Findings: Blood B12 increased, but no significant benefits were found in primary neurological measures or cognition.
KNOWLEDGE RECORD
- Category
- Vitamins and minerals
- Last Reviewed
Names and related search termsVitamin B12 / Vitamin B12 / Cobalamin
Study type: human intervention study.
OUTCOME-SPECIFIC EVIDENCE
Scientific Evidence Profile
Assessment pending
An outcome-specific assessment has not yet been completed. This is not a finding that the ingredient is ineffective. The study records below remain available.
This profile concerns the stated outcome and population, not the ingredient as a whole. It is not a probability of benefit, a safety rating, a product efficacy rating or an indication of product adoption.
How we assess evidenceIngredient Profile
- What is it, and where is it found?
- Vitamin B12 is water-soluble and contains cobalt. Animal foods and fortified foods are sources; absorption involves several steps, not simply the amount eaten. [1]
Sources for this profile
Compound properties and formulation properties are different. These sources do not establish the efficacy of a finished supplement.
- NIH Office of Dietary Supplements — VitaminB12 Nutrient identity and food-source reference. Published by NIH Office of Dietary Supplements. Reference synthesis; not an individual clinical trial.
Profile sources checked:
Read the evidence in context
- Evidence: what was measured in the stated population or experimental model.
- Inference: an interpretation connecting findings; its applicability depends on the study conditions.
- Hypothesis: a proposed explanation or effect that remains to be tested.
Why It Matters #
Does improving blood concentrations directly improve cognition? Check the detailed records for study conditions and use the literature map to compare other populations and outcomes.
What Was Studied #
201 adults aged 75 or older with moderate B12 deficiency but no anemia or neurological or cognitive symptoms. Randomized, double-blind, placebo-controlled trial. Outcomes: Neurological function, including tibial nerve compound muscle action potential[1]
What Was Found #
Blood B12 increased, but no significant benefits were found in primary neurological measures or cognition.[1]
What the Evidence Means #
A specific asymptomatic population. This does not imply that symptomatic B12 deficiency need not be treated.[1]
Comparing similar populations, formulations, durations and outcomes helps identify where findings agree and where they differ.
What We Can Learn #
Distinguish laboratory values, symptoms and treatment goals. Higher blood concentrations alone do not establish brain health benefits.
What Remains Unknown #
Further questions include reproducibility across populations and formulations, and the long-term balance of benefits and harms. Use the literature map as a starting point for these questions.
LITERATURE MAP / 10 PAPERS
Compare papers by conditions and findings.
A literature map covering different populations, outcomes and formulations. Read alongside detailed records to avoid treating one trial as the conclusion for an entire ingredient.
Selected: 2026-09-21. Bibliographic information checked against Europe PMC / PubMed. Editorial selection considered major papers and a range of populations and questions. This is not a systematic search covering all recent research.
10 RECORDS
A dash marks fields outside the bibliographic record. Use detailed records to compare findings and design records to connect mechanisms.
No papers match. Change the search conditions.
The literature map is an index of research questions and references. Individual assessment of results, doses, funding and COI is limited to the detailed study records. Related reports from the same trial may be included; paper counts are not counts of independent trials.
Explore the research Study Records
Listed doses describe study conditions, not recommended intake.
Effects of vitamin B-12 supplementation on neurologic and cognitive function in older people: a randomized controlled trial.
PubMed 26135351DOI: 10.3945/ajcn.115.110775
- Authors
- Dangour AD, Allen E, Clarke R, Elbourne D, Fletcher AE, Letley L, Richards M, Whyte K, Uauy R, Mills K.
- Journal
- The American journal of clinical nutrition
- Publication year
- 2015
- Study design
- Randomized, double-blind, placebo-controlled trial
- Participants
- 201 eligible adults aged at least 75 with moderate B12 deficiency but no anemia or neurological/cognitive symptoms; 191 provided 12-month outcomes.
- Dose and intervention
- Crystalline vitamin B12 1 mg/day
- Duration
- 12 months
- Outcomes and their role in the study
- Neurological function, including tibial nerve compound muscle action potential
- Findings
- Blood B12 increased, but no significant benefits were found in primary neurological measures or cognition.
- Limitations
- A specific asymptomatic population. This does not imply that symptomatic B12 deficiency need not be treated.
- Funding
- Supported by the Food Standards Agency, Department of Health and others. DSM supplied the B12 ingredient.
- Conflict of Interest
- The authors reported no study-related conflicts of interest.
- Scope of source review
- Primary-paper methods, relevant results, limitations and funding/COI checked on 2026-10-24. This record assesses the stated claims, not every analysis in the paper.
Cite this page
LÍFSVARÐA. Vitamin B12: Does improving blood concentrations directly improve cognition? Version 1.1 / Updated 2026-10-24
https://lifsvarda.com/knowledge/vitamin-b12/Edited by LÍFSVARÐA (product brand).Editorial policy
Sources and updates
- Dangour AD, Allen E, Clarke R, Elbourne D, Fletcher AE, Letley L, Richards M, Whyte K, Uauy R, Mills K. (2015). Effects of vitamin B-12 supplementation on neurologic and cognitive function in older people: a randomized controlled trial.Primary-paper methods, relevant results, limitations and funding/COI checked on 2026-10-24. This record assesses the stated claims, not every analysis in the paper.
First published: 2026-09-21 / Version 1.1. Updated 2026-09-23: Added a research comparison table and links to design records. Source notes identify the scope of verification when the full paper has not been reviewed. Research summaries and LÍFSVARÐA’s interpretation are distinguished.