Effects of vitamin D supplementation on vitamin D status and physical performance in football players: A systematic review and meta-analysis.

Low vitamin D status is frequently reported among athletes, but whether vitamin D supplementation improves physical performance in football players remains uncertain. This systematic review and meta-analysis aimed to evaluate the effects of vitamin D supplementation on serum 25-hydroxyvitamin D [25(OH)D] concentration, jump performance, sprint performance, aerobic capacity, and muscular performance in association football and futsal players.

PubMed, Embase, the Cochrane Library, Scopus, and Web of Science were searched from database inception to 31 May 2026. Controlled intervention studies comparing vitamin D supplementation with control conditions were eligible. Standardized mean differences were calculated as Hedges' g and pooled using random-effects meta-analyses. Two reviewers independently extracted data and assessed risk of bias using RoB 2 or ROBINS-I. The certainty of evidence was assessed using GRADE. The protocol was prospectively registered in PROSPERO (CRD420261430873).

Eleven reports representing nine independent studies and 312 players were included. In RCT-only primary analyses, vitamin D supplementation was associated with higher circulating 25(OH)D concentrations (g = 1.41, 95% CI 0.90 to 1.92; I² = 58.0%). Pooled effects were not statistically significant for jump performance (g = 0.21, 95% CI -0.10 to 0.53), sprint performance (g = -0.03, 95% CI -0.40 to 0.34), aerobic capacity (g = 0.00, 95% CI -0.45 to 0.45), or muscular performance (g = 0.19, 95% CI -0.14 to 0.51). The certainty of evidence was low for circulating 25(OH)D, jump performance, and muscular performance, and very low for sprint performance and aerobic capacity.

Vitamin D supplementation was associated with increased circulating 25(OH)D concentrations, whereas current evidence is insufficient to support a consistent improvement in physical performance. Given the low to very low certainty of evidence, these findings should be interpreted cautiously. Larger, well-designed randomized controlled trials using standardized, football-relevant performance tests are warranted.