Vitamin B—Can it prevent cognitive decline? A systematic review and meta-analysis
What this study found
Oral vitamin B supplementation did not significantly prevent cognitive decline in cognitively unimpaired adults. Global cognition showed no meaningful improvement (pooled effect near zero; 95% CI includes 0; p > 0.05; sensitivity analysis with reduced heterogeneity also non-significant). Some secondary cognitive domains showed isolated significant effects in individual trials, but findings were inconsistent across populations and may reflect chance or bias. No evidence that any particular population group benefits more; results apply only to oral administration and to cognitively unimpaired…
- Study & population
- Design: randomized, placebo-controlled trials (RCTs).
- Intervention
- Oral vitamin B regimens using folic acid with vitamins B6 and B12, administered in single or combination formulations; treatment durations ranged from 5 weeks to 6.6 years; taken orally.
- Key limitation
- High heterogeneity across trials (differences in populations, interventions, durations, and cognitive outcomes); reliance on MMSE/TICS-m for global cognition in many studies with known limitations; many trials had small samples and some risk of bias; broad array of cognitive tests limits comparability; potential…
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Open PDFOriginal abstract
Background Development of cognitive decline represents substantial issues in today’s society, steadily gaining importance with increasing life expectancy. One potential approach to preventing cognitive decline is to lower homocysteine by administering vitamin B. In this systematic review and meta-analysis, we address this topic and investigate whether oral supplementation of vitamin B can successfully prevent cognitive decline in cognitively unimpaired individuals. Methods A computerized systematic literature search was conducted using the electronic databases PubMed, Embase, and the Cochrane Library. Eligibility criteria included oral supplementation with vitamin B (B 1 , B 6 , folic acid, and B 12 ) and the absence of cognitive impairment. A meta-analysis was conducted with “global cognition” as the primary outcome of this review. Secondary outcomes were changes in cognitive function in other cognitive domains reported in the included studies. Risk of bias was assessed according to the Cochrane Risk of Bias tool and the GRADE approach to establish the overall certainty of the evidence. Results The meta-analysis did not yield a significant overall effect of supplementation with vitamin B on cognitive function ( Z = 0.87; p = 0.39; SMD, 0.02; 95% CI, − 0.034, 0.08). A sensitivity analysis focusing on specific risk factors did not alter this result. Some studies reported isolated significant effects of the intervention on secondary outcomes. However, these findings were outnumbered by the number of cognitive tests that did not yield significant effects. Discussion We found no overall evidence that oral vitamin B supplementation prevented cognitive decline. The isolated significant effects that were reported could be attributed to methodological issues. The results of this review do not provide evidence that population groups with certain risk factors would profit more from the intervention than others. Our findings do not apply to forms of administration other than oral supplementation nor do they offer information regarding the treatment of cognitively impaired individuals via the administration of vitamin B. Systematic review registration PROSPERO CRD42017071692