B vitamins and prevention of cognitive decline and incident dementia: a systematic review and meta-analysis
Wang Z, et al.
Published in Nutrition Reviews
Methodology
Systematic review and meta-analysis of randomised controlled trials and prospective cohorts of B vitamin supplementation reporting cognitive test scores or incident dementia, with pooled effect estimates and subgroup analyses.
Key Findings
Meta-analysis pooling around 46,000 participants found B vitamin supplementation (folic acid, B6, B12) lowered homocysteine but produced no significant benefit for global cognition, episodic memory, executive function or incident dementia risk in older adults; subgroup signals in those with elevated homocysteine or low baseline B12 were inconsistent.
Conclusions
Routine B vitamin supplementation does not prevent cognitive decline or dementia in generally replete older adults, despite reliably lowering homocysteine.
Limitations
Heterogeneous doses, formulations and cognitive instruments across trials; most participants were nutritionally replete; follow-up durations may be short relative to dementia latency; subgroup analyses underpowered and exploratory.
Supplements Studied
Higher intake of dietary folate, but not B12 or B6, is associated with a reduced risk of incident dementia.
B vitamin supplementation is associated with slowing of cognitive decline, especially in populations who received early intervention and intervention of long duration.
Outcomes Measured
Meta-analysis pooling around 46,000 participants found B vitamin supplementation (folic acid, B6, B12) lowered homocysteine but produced no significant benefit for global cognition, episodic memory, executive function or incident dementia risk in older adults; subgroup signals in those with elevated homocysteine or low baseline B12 were inconsistent.
Related Health Concerns
Study Details
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Disclosures
Funding
Academic and national research funding
This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.