Abstract
- Background
A systematic review and meta-analysis was undertaken to examine and quantify the effects of B vitamin supplementation on mood in both healthy and "at-risk" populations.
- Methods
A systematic search identified all available randomized controlled trials (RCTs) of daily supplementation with $\ge 3$ B group vitamins with an intervention period of at least four weeks. Random-effects models for a standardized mean difference ($\text{SMD}$) were used to test for overall effect, and heterogeneity was evaluated using the $I^2$ statistic. Eighteen articles (16 trials, 2015 participants) were included, of which 12 were eligible for meta-analysis.
- Results
Eleven of the 18 articles reported a positive effect for B vitamins over a placebo for overall mood or a facet of mood. Of the eight studies in "at-risk" cohorts, five found a significant benefit to mood. Regarding individual facets of mood, B vitamin supplementation benefited stress ($n = 958$, $\text{SMD} = 0.23$, $95\%\text{ CI} = 0.02\text{ to }0.45$, $p = 0.03$). A benefit to depressive symptoms did not reach significance ($n = 568$, $\text{SMD} = 0.15$, $95\%\text{ CI} = -0.01\text{ to }0.32$, $p = 0.07$), and there was no effect on anxiety ($n = 562$, $\text{SMD} = 0.03$, $95\%\text{ CI} = -0.13\text{ to }0.20$, $p = 0.71$).
- Conclusions
The review provides evidence for the benefit of B vitamin supplementation in healthy and at-risk populations for stress, but not for depressive symptoms or anxiety. B vitamin supplementation may particularly benefit populations who are at risk due to (1) poor nutrient status or (2) poor mood status.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6770181/