Effects of vitamin D supplementation on vitamin D status and physical performance in football players: A systematic review and meta-analysis.
Jinfa Gu, Yu Zhang, Luhua Xiao
✦ AI-curated · Sources linked
In 30 seconds
This systematic review and meta-analysis assessed controlled intervention studies of vitamin D supplementation in association football and futsal players. Eleven reports from nine independent studies, involving 312 players, were included; primary analyses were restricted to randomized controlled trials. Supplementation was associated with higher circulating 25(OH)D concentrations (Hedges’ g = 1.41, 95% CI 0.90 to 1.92), but pooled effects were not statistically significant for jump, sprint, aerobic, or muscular performance. Evidence certainty ranged from low to very low, so performance effects remain uncertain.
Key findings
- In RCT-only analyses, supplementation was associated with higher 25(OH)D concentrations (g = 1.41, 95% CI 0.90 to 1.92; I² = 58.0%).
- Jump performance showed no statistically significant pooled effect (g = 0.21, 95% CI -0.10 to 0.53).
- Pooled effects were not statistically significant for sprint performance (g = -0.03, 95% CI -0.40 to 0.34) or aerobic capacity (g = 0.00, 95% CI -0.45 to 0.45).
- Muscular performance showed no statistically significant pooled effect (g = 0.19, 95% CI -0.14 to 0.51).
Why it matters
The findings distinguish improvement in a biochemical measure from demonstrated improvement in athletic performance. For football and futsal players, supplementation increased circulating 25(OH)D in the pooled randomized analyses, but the available evidence does not establish consistent gains across the performance outcomes assessed. The low or very low certainty warrants caution when interpreting these results.
What to keep in mind
The evidence base comprised nine independent studies and 312 players, and certainty was low for several outcomes and very low for sprint performance and aerobic capacity.