Introduction:
Vitamin D deficiency, which is on the rise, can put any athlete at an increased susceptibility to various musculoskeletal injuries and prolonged recovery. It was intended to determine whether vitamin D supplements can help athletes to enhance their performance and body composition, and to determine which physical components of the athlete correlates with vitamin D inadequacy and vitamin D supplementation.

Methods:
Study eligibility criteria – randomized controlled trials (RCT) and quasi-experimental studies that examined the effect of vitamin D supplementation in athletes performed during 2015–2019. The participants were athletes aged 20–40, including both sexes. Study appraisal – Pedro score.

Results:
A total number of 43 studies were analysed, out of which 10 studies were selected for the final review (8 were double-blinded RCT and 2 were non-blinded RCT) reports. All the trials used 25-hydroxy vitamin D (25(OH)D) as the primary outcome measure to analyse the vitamin D levels. Studies were performed on subjects belonging to a variety of sports like football, rowing, winter sports, taekwondo, rugby and swimming. Except for one study, all the other studies reported that there was a significant improvement in the vitamin D levels after supplementation irrespective of the mode of administration. Higher doses of vitamin D3 had resulted in better improvement over a short period.

Conclusions:
This systematic review analysis concludes that vitamin D inadequacy, which results in many physical derangements and compromised performance levels of athletes, can be restored by supplementing with vitamin D.