Associations of dietary vitamin B1, vitamin B2, vitamin B6, and vitamin B12 with the risk of depression: a systematic review and meta-analysis

Abstract Context The results from epidemiologic studies on the intake of dietary vitamin B1, B2, B6, and B12 and association with risk of developing depression have been inconsistent. Objective The purpose of this systematic review and meta-analysis was to summarize the existing evidence and synthesize the results. Data Sources The databases of Web of Science and PubMed were searched for relevant articles published in English until September 2020. Study Selection Observational studies that evaluated the associations between depression and dietary vitamin B1, B2, B6, and B12 were included in this study. Data Extraction The job of data extraction was undertaken by 2 authors, and the pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a fixed-effects model. Results Thirteen articles related to 18 studies were eligible for inclusion in this systematic review and meta-analysis. The pooled RR (95% CI) of depression for the highest vs the lowest category of dietary vitamin B1, B2, B6, and B12 was 0.69 (0.55–0.87), 0.77 (0.67–0.89), 0.81 (0.71–0.93), and 0.86 (0.75–0.99), respectively. The pooled RR (95% CI) of depression for the highest vs the lowest category of dietary vitamin B2 was 0.80 (0.64–0.99) in females and 0.83 (0.67–1.02) in males, for dietary vitamin B6 was 0.71 (0.59–0.86) in females and 0.92 (0.76–1.12) in males, and for dietary vitamin B12 was 0.79 (0.65–0.97) in females and 0.94 (0.77–1.15) in males. Conclusion This study suggested that the intake of dietary vitamin B1, B2, B6, and B12 may be inversely associated with the risk of depression; the inverse associations observed between depression and intake of dietary vitamin B2, B6, and B12 were significant in females, but not in males. Further studies are needed to confirm these results.