Vitamin B12
Research reviewed: Up until 03/2026
Vitamin B12 is a dietary supplement with 2 published peer-reviewed studies involving 360 participants, researched for Cognitive Health.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Cognitive Health
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Cognitive Health
To evaluate the combined action of folic acid and vitamin B12 supplementation on cognitive performance and inflammation in patients with Alzheimer's disease.
Study Type
Randomized, single-blind, placebo-controlled trial
Purpose
To evaluate the combined action of folic acid and vitamin B12 supplementation on cognitive performance and inflammation in patients with Alzheimer's disease.
Dose
1.2 mg/d folic acid + vitamin B12 50 μg/d or placebo
Participants
120 patients with Alzheimer's Disease and in stable condition (101 completed)
Duration
6 months
Results
Researchers observed that folic acid plus vitamin B12 supplementation significantly improved several aspects of cognitive function compared to controls, including MoCA scores (a test of overall thinking and memory ability), naming ability, orientation (awareness of time and place; P = 0.004), and attention measured. The supplementation also significantly increased SAM (S-adenosylmethionine - a compound important for brain function and cell repair) and the SAM/SAH ratio (a marker of healthy cell processes), while significantly decreasing homocysteine (a harmful amino acid linked to heart and brain problems), SAH (a compound that builds up when cell processes are impaired), and TNFα (a marker of inflammation in the body). Overall, this suggests the vitamins may help improve brain function while also supporting healthier metabolism and reducing inflammation.
To determine whether supplementation with folic acid and vitamin B12, alone and in combination improves cognitive performance
Study Type
Single-blind Experimental Design
Purpose
To determine whether supplementation with folic acid and vitamin B12, alone and in combination improves cognitive performance
Dose
800 µg/day folic acid alone (2 x 400 µg tablets) or 25 µg/day vitamin B12 alone (1 x 25 µg tablet) or 400 µg/day folic acid +25 µg/day vitamin B12, or control (no treatment).
Participants
240 participants with mild cognitive impairment
Duration
6 months
Results
Researchers observed that the group taking folic acid plus vitamin B12 showed significant improvements compared to the control group in several blood markers, including serum folate (levels of folic acid in the blood), vitamin B12, and homocysteine (a harmful substance linked to heart and brain problems; lower is better), as well as reductions in inflammatory markers like IL-6, TNF-α, and MCP-1 (proteins that increase during inflammation in the body). They also had significant improvements in cognitive function, including Full Scale IQ (overall thinking ability), verbal IQ (language and understanding), Information (general knowledge), and Digit Span (memory and attention). Further analysis showed the combined vitamins were significantly more effective than folic acid alone. Overall, taking both vitamins for 6 months helped improve brain function and reduce inflammation in older adults with mild cognitive impairment.
Frequently Asked Questions
Common questions about Vitamin B12 research
There are currently 2 peer-reviewed studies on Vitamin B12 (Vitamin B12), involving 360 total participants. Research covers Cognitive Health. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (2 human studies), and reported outcomes.
Vitamin B12 has been researched for: Cognitive Health. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 2 out of 2 studies are human trials. Human trials carry more weight in our evidence scoring system.
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