The Most Important Supplement for Athletes- Vitamin D

Jun 5th, 2016

Category: Nutrition

The Most Important Supplement for Athletes- Vitamin D

Referred to as the “sunshine vitamin”, Vitamin D is produced by the body after the skin is exposed to sunlight. Vitamin D deficiencies are very common, especially in indoor athletes that have limited sun exposure. One study showed that 3/4 of U.S. teens and adults are deficient in Vitamin D (1). The health implications of Vitamin D deficiencies are very well documented, and the performance implications are now being heavily studied.

Evidence suggests that treatment of vitamin D-deficient athletes may improve athletic performance. Increases in power, speed and cardiovascular ability have been correlated with Vitamin D (2). More importantly for athletes, adequate vitamin D levels have been linked to decreased risk of bone fractures along with immune function. The common belief is that increased vitamin D ABOVE recommended levels will NOT improve performance, however, Vitamin D-deficient athletes will see large improvements when treated.

A study conducted on professional basketball players showed that hoopers are at a higher risk of low vitamin D levels after wintertime (3). In addition to pro players, high school and college basketball players spend most of their time in the classroom and in the gym, which leaves little time for sun exposure. For teams that play in areas with adequate sunlight it may be a good idea to schedule outdoor warmups and cool downs whenever possible.

A fair skinned person may need just 15 minutes of bare skin exposure (shorts and tank top without sunscreen). Darker people need significantly more sunlight because melanin protects the skin against ultraviolet light. A study led by Dr. Adam Murphy showed that black men in Chicago were up to 3.5 times more likely than white men to be deficient in vitamin D. Based on his findings, Murphy suggests a black man in Chicago needs at least 90 minutes, three times a week in the sun to produce the same amount of vitamin D a white man in Chicago can in 15 minutes three times per week (4).

According to, “The closer to midday you expose your skin, the better this angle and the more vitamin D is produced. A good rule of thumb is if your shadow is longer than you are tall, you’re not making much vitamin D. In winter, you’ll notice that your shadow is longer than you for most of the day, while in summer, your shadow is much shorter for a good part of the middle of the day (5).”

Because it’s so difficult for indoor athletes to get the necessary exposure, it’s very important to take a vitamin D3 supplement. There are dietary sources such as oily fish and egg yolks; however, it’s unlikely to achieve the necessary Vitamin D requirements through your diet.

Personally, I think Vitamin D supplementation is the single most important supplement for indoor athletes and anyone who doesn’t meet the requirements. Vitamin D supplementation not only improves sports performance; it also decreases risk of injury and sickness, which is crucial for all athletes.

Talk to your doctor and schedule a blood test every 3 months to assess your Vitamin D levels. Excess Vitamin D can be toxic so it’s important to know your current levels and plan sun exposure/supplementation accordingly.


2. Nikolaos Koundourakis, et. al., “Vitamin D and Exercise Performance in Professional Soccer Players

3.Garcia RB, et al Low levels of vitamin D in professional basketball players after wintertime: relationship with dietary intake of vitamin D and calcium.




  1. Ben June 8, 2016 at 4:11 PM

    What about drinking Vitamin D (whole) milk? Will that help?

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