What role does Vitamin D 25-OH play in Sport?

Vitamin D (25-OH) plays a supportive, not performance-enhancing, role in sports. It is crucial for calcium absorption and bone health, helping prevent injuries like stress fractures. It also influences muscle function and immune response – deficiency can lead to reduced muscle strength, slower recovery, and higher infection risk. Studies show that supplementation in deficient individuals can improve performance, but no added benefit exists for those with adequate levels. Evidence for direct performance enhancement is moderate, mostly from observational studies. A blood test for 25-OH vitamin D is advisable to determine status before supplementing. Overdosing is rare but possible. In summary: vitamin D is an important micronutrient for athletes, but not a magic bullet. Individual assessment via lab testing is recommended.