Vitamin D, the “sunshine vitamin”, is found naturally in small amounts in some foods, including fatty fishes. In an effort to make it more available to the public, it is also now added to dairy products, juices, and cereals. While many understand vitamin D to be essential for optimal bone health, the discovery of vitamin D muscle receptors in the last few years has suggested the significant role it may play in the world of athletics.
Although up to a billion people worldwide may have insufficient vitamin D levels, athletes are of particular interest due to the recent discovery of the receptors in muscle tissue. In a systematic-review and meta-analysis by Farrokhyar et al., 56% of the analyzed athletes had inadequate vitamin D levels. When sports injuries were studied, 43% were bone-related and 37.5% were muscle-related.
Villacis et al. measured vitamin D levels in NCAA Division I athletes. They found that of the 223 participants, 148 had sufficient vitamin D levels and 75 had insufficient (moderately low) or deficient (very low) levels. Recent studies highlighted in a review by von Hurst et al. have shown that interventions with vitamin D supplementation have mixed results, with positive effects only observed in those who previously had moderately low statuses. Dubnov-Raz et al., showed that there was no significant difference in performance between vitamin D deficient groups who received a supplement and those who received a placebo throughout the study.
While there are currently mixed results about the effects of vitamin D supplementation on athletes, one thing is clear: vitamin D inadequacy in athletes is prominent. Since some studies do suggest a relationship between serum vitamin D levels and factors such as muscle power, force, velocity, optimal bone mass, and an increased risk of low trauma fractures and muscle injuries, it would be a good idea to supplement athletes with low vitamin D levels in the hopes of preventing injury and increasing performance. However, as usual, more research is needed to discover the exact effects.
In the meantime, get your sunshine on!
Feature Image Source: Steven Pisano