The effect of vitamin D supplementation on depressive symptoms in adults: A systematic review and meta‐analysis of randomized controlled trials

Mikola T, Marx W, Lane MM, Hockey M, Loughman A, Rajapolvi S, Rocks T, O’Neil A, Mischoulon D, Valkonen-Korhonen M, Lehto SM, Ruusunen A · Critical Reviews in Food Science and Nutrition · 2022 July 11

DOI 10.1080/10408398.2022.2096560

Objective

Neurosteroid and immunological actions of vitamin D may regulate depression-linked physiology. Meta‐analyses investigating the effect of vitamin D on depression have been inconsistent. This meta-analysis investigated the efficacy of vitamin D in reducing depressive symptoms among adults in randomized placebo-controlled trials (RCT).

Conclusions

Notwithstanding high heterogeneity, vitamin D supplementation ≥ 2,000 IU/day appears to reduce depressive symptoms. Future research should investigate possible benefits of augmenting standard treatments with vitamin D in clinical depression.

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Insights

Vitamin D supplementation, particularly in doses greater than 2,000 IU/day, can help reduce depressive symptoms in adults.

In the methodology, a comprehensive database search (including Medline, PsycINFO, CINAHL and The Cochrane Library) was performed to identify English language articles relating to the impact of Vitamin D on depression in adults, published before April 2022. This meta-analysis considered both general and clinical populations and also included studies of individuals suffering from systemic diseases, but excluded studies involving light therapy, co-supplementation (except calcium), and bipolar disorder. During the assessment of the work, the Cochrane risk-of-bias tool (RoB 2) and GRADE standards were employed to appraise the validity of each study. The results revealed a positive effect of Vitamin D on alleviating depressive symptoms. Despite the presence of high heterogeneity within included studies and with the majority having concerns related to risk of bias, it was found overall that Vitamin D supplementation, particularly when administered at doses about 2,000 IU/day, could serve as a valuable solution in reducing depressive conditions. This offers an interesting angle for mental health treatment, suggesting the supplement could be a useful addition to standard therapeutic procedures for clinical depression.