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Nutrition for Women

The Athlete’s Guide to Vitamin D

Vitamin D affects more than just your bones — it also plays an important role in muscle strength, performance and recovery. 

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Vitamin D is best known for its role in building and maintaining bones, and in the past couple of years, it has taken center stage because of its anti-inflammatory capacity and role in boosting immunity. But this essential nutrient wears many more functional hats, especially when it comes to athletes. 

“Vitamin D helps the body absorb calcium and helps keep [that calcium] in the bloodstream,” says Wendy Bazilian, DrPH, MA, RDN, author of Eat Clean, Stay Lean: The Diet (Rodale Books, 2016). This means that calcium is at the ready to facilitate muscle contractions — imperative during exercise — and prevents your body from pulling it out of other areas like your bones for immediate use, she explains.

Training in general causes oxidative stress, making anti- inflammatory vitamin D a must-have for active women. “Exercise taxes the immune system … so ensuring adequate vitamin D intake is critical for optimizing performance, training and recovery,” Bazilian says. “Plus, it keeps the immune system strong, countering inflammation and other life stressors.” 

Are You D-ficient? 

Common symptoms of vitamin D deficiency include fatigue, frequent illness, depression and hair loss, but athletes will likely notice issues with their physical person
first. “A common symptom of being vitamin D deficient is muscle weakness and decreased physical performance,” says Orit Markowitz, M.D., board-certified dermatologist and founder of OptiSkin in New York City. A long-term deficiency could have serious consequences, she adds. “If your levels are not up to par, you could end up with osteoarthritis or … osteopenia [bone thinning and breakage].” 

D-termine Your Needs 

Vitamin D is pretty easy to obtain naturally through sun exposure, but even though bathing in the sun’s rays revs up your natural D production, that isn’t a hall pass to toast yourself. “UV radiation can be very harmful and causes wrinkling, aging, sunspots and a greater risk of skin cancer,” Markowitz says. “Always wear sunscreen with at least an SPF of 15, even if it appears cloudy outside.” However, while it prevents burning, sunscreen also limits the amount of vitamin D you can produce. 

Here’s where diet comes in. Active people should regularly eat high-D foods such as fatty fish (salmon, herring and sardines), canned tuna, mushrooms and egg yolks, as well as products fortified with vitamin D such as cow’s milk, yogurt, tofu and orange juice. 

Because vitamin D is fat-soluble, dietary fat must be present to optimize its absorption. When planning meals, pair vitamin D–rich foods with healthy fats such as olive oil and avocado for best results. 


Hard-hitting athletes might still want to consider supplementation to achieve optimal vitamin-D levels. The recommendation for adults younger than 70 is 600 IU. “But many health professionals feel that athletes need more,” Bazilian says. “Generally, 1,000 to 2,000 IU is recommended and well-tolerated, with an upper limit set at around 4,000 IU.” According to Bazilian, a D3 supplement (derived from animal sources) is better absorbed and assimilated in the body than D2 (derived from plant sources), but truthfully, both are valuable additions to an athlete’s regimen. class=”Apple-converted-space”>

Much like our skin, mushrooms can produce vitamin D when exposed to UV rays. Slice your ‘shrooms to increase their overall surface area. Then place them in direct sunlight four to six hours before using to significantly increase their concentration of D. 


Vitamin D is really a hormone!

“It’s actually a prohormone,” Orit Markowitz says. “It converts into a hormone that controls calcium levels and impacts the immune system.”