The effectiveness of vitamin D supplementation in reducing depressive symptoms: A systematic review and meta-analysis of Randomized Controlled Trials (RCTs)

BACKGROUND: Depression is a widespread, global problem, increasingly linked with vitamin D deficiency in the literature. However, knowledge gap persists regarding relationship between depressive symptoms and intake. OBJECTIVE: To determine association supplementation adults (aged 18+ years). METHODS: This study consists of systematic review meta-analysis randomized controlled trials (RCTs), published before January 2019. Pooled summary estimates between-study heterogeneity were examined. RESULTS: Ten RCTs (total participants = 3336; median duration 12 months) included. An was found high (≥4000 IU) reduced symptoms, but not case lower levels (<4000 IU). Neither baseline serum supplementation, nor depression-scoring scales used affected this association. The overall quality evidence graded as ‘moderate’. CONCLUSIONS: Vitamin at greater than 4000 IU observed to have positive effect on symptoms. Future efforts could focus obtaining higher-quality standardized RCT methodologies confirm