Abstract
Introduction: Vitamin D (VD) deficiency (serum 25-hydroxyvitamin D (25 (OH) D) <50 nmol/L or 20 ng/mL) is more common than is thought in the majority of the world population. In this context, athletes have the same predisposition to low levels of vitamin D, with the majority of their concentrations below 20 ng/mL in a wide variety of sports, especially in the winter months. RV is also essential in extra-skeletal functions, including skeletal muscle growth, immune and cardiopulmonary functions, and inflammatory modulation, which influence athletic performance. Vitamin D can also interact with extra-skeletal tissues to modulate injury recovery and also influence the risk of infection. Objective: Performed a wide analysis of the world literature to compose the State of the Art on the main effects of vitamin D supplementation on the performance of athletes through randomized clinical studies, meta-analysis, and the latest international conferences and consensus. Methods: The present study followed a broad literature review of randomized clinical studies, meta-analysis, and the latest international consensus. The Cochrane instrument was adopted to assess the quality of the studies. Main findings and conclusion: One of the main aspects that must be taken into account is important evidence that suggests that free (bioavailable) 25(OH)D may be a better marker of vitamin D status. Many researchers do not take into account that athletes may need a greater supply of vitamin D to meet the requirements of muscle metabolism due to the potential routes of vitamin D use. A significant debate seems to be needed to determine and standardize the classification of vitamin D deficiency. There are still information gaps on the correlation between vitamin D supplementation and athletes' exercise performance. However, because vitamin D induces myogenesis and muscle protein synthesis, causing an increase in the percentage of rapidly contracting muscle cells, and because vitamin D receptors (VDR) play a significant role in muscle regeneration after injury, supplementation in athletes is recommended.