Cheng · Depression and anxiety 2020 · systematic review and meta-analysis · n=7,534

The effect of vitamin D supplement on negative emotions: A systematic review and meta-analysis.

Cited 112 times in the scientific literature.

Level 1 - systematic review of randomized trials

Systematic review and meta-analysis of randomized controlled trials

PubMed 32365423 · doi:10.1002/da.23025 · record verified 2026-08-27

What was done

Systematic review and meta-analysis of randomized controlled trials published before February 2019 comparing the effect of vitamin D versus placebo on negative emotions. Subgroup analyses examined clinical depression status, baseline serum 25(OH)D levels, dosage, and intervention duration.

What was found

Across 25 trials including 7,534 participants, vitamin D significantly reduced negative emotions compared to placebo (Hedges' g = -0.4990, 95% CI [-0.8453, -0.1528], p = .0047; I² = 97.7%). Significant effects were observed in subgroups with major depressive disorder, baseline serum 25(OH)D ≤ 50 nmol/L, duration ≥ 8 weeks, and dosage ≤ 4,000 IU/day; exact numerical effect sizes for subgroups were not provided in the abstract.

Why it matters

This meta-analysis suggests vitamin D supplementation can improve negative emotional outcomes, especially in individuals with baseline deficiency or major depressive disorder.

Limits

Statistical heterogeneity across included trials was exceptionally high (I² = 97.7%). The abstract does not provide numerical effect estimates or confidence intervals for the subgroup analyses, nor does it report trial risk of bias or separate outcomes for anxiety versus depression.

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