Vitamin B complex and brain

What 2 graded rows on vitamin b complex agree on for brain, and where they differ. Counted side by side, never averaged.

Consensus finder Rows from the Vitamin B complex page, reviewed Oct 21, 2026 How it decides

What the rows agree on

Each block and row is one graded row from the Vitamin B complex page, with its PubMed record.

Supplement

Vitamin B complex Choose another

2 rows · 5,443 people

They agree: both rows found an improvement.

No difference

Improved

Each block is one evidence row, sized by how many people it enrolled, with its grade inside.

From the rows

The best-graded row, grade B, is a meta-analysis of 5,275 people (2025) and found an improvement.

The rows run from 168 to 5,275 people, published from 2010 to 2025: 1 pooled review and 1 single study.

2 improved

Grade BGlobal cognitive function in older adults · Improved
Meta-analysis, 17 studies · n 5,275 · 2025 · Adults aged 60 and over in 17 RCTs lasting at least 26 weeks, with intact cognition, mild cognitive impairment or dementia
Any dose or route; varied by trial · 26 weeks or longer
Pooled global cognition improved (Hedges' g 0.42) but with very high heterogeneity (I² 93%, very low certainty). Without outlier and single-blinded studies the gain was very small (g 0.11; 95% CI 0.03 to 0.19; high certainty), and it did not differ by cognitive status.
Row on the Vitamin B complex page · PubMed 40966571 (opens PubMed)
Grade CRate of brain shrinkage in mild cognitive impairment · Improved
RCT · n 168 · 2010 · Adults over 70 with mild cognitive impairment (UK; MRI subset)
0.8 mg folic acid, 20 mg B6, 0.5 mg B12 daily · 24 months
Whole-brain atrophy 0.76% per year vs 1.08% with placebo.
Row on the Vitamin B complex page · PubMed 20838622 (opens PubMed)