The effect of vitamin D supplementation on depressive symptoms in adults: A systematic review and meta‐analysis of randomized controlled trials
What this study found
Vitamin D supplementation was associated with a small-to-moderate reduction in depressive symptoms overall. The pooled effect at the end of supplementation was Hedges' g = -0.317, 95% CI [-0.405, -0.230], p < 0.001, with substantial heterogeneity (I2 = 88.16%). Effects were larger in major depressive disorder (g = -0.729, 95% CI [-1.100, -0.358]) and perinatal mothers (g = -0.930, 95% CI [-1.229, -0.632]), while healthy participants showed little to no benefit (g = 0.043, 95% CI [0.025, 0.061]). Larger effects were reported with shorter duration, higher daily doses, and in participants with…
- Study & population
- Systematic review and meta-analysis of 41 randomized controlled trials in 53,235 adults.
- Intervention
- Vitamin D supplementation was tested, most commonly as oral cholecalciferol, with some trials using ergocalciferol or calcitriol and a few using intramuscular administration.
- Key limitation
- Evidence certainty was very low, and the pooled results were highly heterogeneous.
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Open PDFOriginal abstract
Abstract 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). General and clinical populations, and studies of ill individuals with systemic diseases were included. Light therapy, co-supplementation (except calcium) and bipolar disorder were exclusionary. Databases Medline, PsycINFO, CINAHL and The Cochrane Library were searched to identify relevant articles in English published before April 2022. Cochrane risk-of-bias tool (RoB 2) and GRADE were used to appraise studies. Forty-one RCTs (n = 53,235) were included. Analyses based on random-effects models were performed with the Comprehensive Meta-analysis Software. Results for main outcome (n = 53,235) revealed a positive effect of vitamin D on depressive symptoms (Hedges’ g = −0.317, 95% CI [−0.405, −0.230], p < 0.001, I2 = 88.16%; GRADE: very low certainty). RoB assessment was concerning in most studies. 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. PROSPERO registration number: CRD42020149760. Funding: Finnish Medical Foundation, grant 4120 and Juho Vainio Foundation, grant 202100353.