Recent studies have shown children and pregnant women usually have low levels of vitamin D. The New York Times says many athletes can also be added to that list. They point out several studies that show gymnasts and runners have poor vitamin D levels, which could be harming their performance.
Recently, vitamin D has been studied for its health benefits that could help athletes beyond bone health, including aiding muscle development and improving the immune system. However, many are deficient in this important nutrient because few go outside long enough to get the nutrient from the sun or eat enough cod liver oil, said the article.
The New York Times also mentions studies that suggest vitamin D helps athletic performance in sprinters and jumpers. Another study showed athletes who train outside are the fittest in August, when sun exposure gives the most vitamin D.
For those who are deficient, the article suggests 1,000 IU of vitamin D supplements every day.