Deficient in vitamin D? It could be keeping you from maxing out your athletic prowess. A recent study set to be published in the International Journal of Sport Nutrition and Exercise Metabolism found low levels of the vitamin messes with the way your muscles function.
For the study, Oklahoma researchers looked at about 100 college athletes and tracked their vitamin D and calcium intake and the amount of time spent in the sun. Even though the athletes lived in the South, where sunshine is plentiful, many weren't meeting the daily vitamin D recommendations. Nearly one quarter of the athletes logged insufficient levels, which were between 50 and 75 nanomoles per liter (nmol/L). Nine percent had less than 50 nmol/L, qualifying as vitamin D deficient. For comparison purposes, the World Health Organization and Endocrine Society says anything over 75 nmol/L is good to go.
The study researchers also tested the athletes' physical abilities by measuring how high they could jump, how far they could hop on one leg, how quickly they could complete a shuttle run, and the maximum weight they could hold for one squat. The researchers then analyzed whether vitamin D played a role in boosting the athletes' strength and power, and guess what? It did. Low levels of vitamin D correlated to a 15 percent decrease in athletic performance for the vertical jump test, 18 percent for the shuttle run test, 77 percent for the one-rep squat, and a whopping 80 percent for the hop test.
The researchers determined that simply stepping out in the sun won't do enough to help you meet your vitamin D levels (and you should always be wearing your sunscreen anyway). Most athletes who participated in the study actually got the recommended 10 to 45 minutes of sun per day, so the researchers note that it's better to focus on diet instead. Taking vitamin D supplements or eating vitamin D-rich foods, like tuna, salmon, cheese, and egg yolks will help you get there. And to keep regular tabs on your levels, follow the Vitamin D Council's three ways to get tested.