December 10th, 2018
Vitamin D Supplement

Top 6 Reasons Athletes Need a Vitamin D Supplement

Good ol’ Vitamin D! This vitamin plays a critical role in hundreds of reactions and processes in the body and an increasing number of studies are showing many potential health benefits including bone health, muscular function, cognition and reduced risk of certain cancers, heart disease and diabetes. Your body naturally synthesizes vitamin D from radiation from the sun and we also can get adequate vitamin D from certain dairy products. However, there is an overwhelming number of athletes who have deficient serum vitamin D levels which can lead to different health problems and decreased physical potential. Here are our top six reasons athletes should supplement vitamin D.

1. You May Not Have Access to Enough Vitamin D

Getting enough sunlight is critical to producing enough vitamin D naturally in your body. There is a positive correlation between the latitude you live at and the amount of vitamin D you are able to synthesize from the sun’s radiation. One study showed that between November and February in Boston and October and March in Edmonton there is not enough sunlight/radiation to produce vitamin D3 naturally. Thus, if you live up North, you may not even have enough access to sunlight to get enough vitamin D year round. [1]

2. You Are Probably Deficient in Vitamin D

We’d all love to throw on the swimsuit and hit the beach or hit the park during peak sunshine hours every week, but of course life, work and weather gets in the way. A 2012 study on professional soccer players from the English Premier League and a 2011 study on professional football players showed that around 65% of their players had vitamin D deficiencies during winter months for optimal athletic performance and health. Where do you stand? [2][3]

3. Your Skin Tone May Decrease Your Access to Vitamin D

There is a significant correlation between skin tones and vitamin D deficiencies. If you have a darker skin tone, your body may not synthesize vitamin D from the sun efficiently. [4][5]

4. Increase Muscle Size and the Number of Type II (Fast Twitch) Muscle Fibers

Vitamin D supplementation has been shown to potentially increase muscle size and the number of type II (fast twitch) muscle fibers. Don’t worry, you’re not going to turn into a bodybuilder by taking a Vitamin D supplement. However, building muscle through resistance training helps burn fat faster than traditional steady state cardio and it’s important to have your body building muscle at optimal, healthy levels. [6][7]

5. A Vitamin D Supplement May Help Improve Your Athletic Performance

Vitamin D supplementation has been shown to improve athletic performance in vitamin D-deficient athletes. If you do not spend much time in the sun or drink and eat dairy you may see some great benefits from vitamin D supplementation. [8]

6. Improve Bone Health and Decrease Chances of Stress Fractures

Lower serum concentrations of vitamin D may be a predisposing element for bone stress fractures. As athletes, we put our joints and bones under tremendous amounts of stress and pressure. Highly repetitive, load bearing exercises and overuse are the most common cause of a sports stress fracture. Fatigue causes your muscles to transfer the load to your joints and bones which then leads to a host of problems. [9][10]


Vitamin D is a critical nutrient that plays a number of roles inside the body and can be especially important for athletes. When possible you should aim to get in some quality time outdoors where your body will be able to naturally synthesize vitamin D from the sunlight. Obviously you don’t want to overdo it and burn yourself, but a good 15-20 minute outdoor session each day can help boost levels of this awesome vitamin. You should consider supplementing with vitamin D if you live up North and get limited sunshine, or if you are stuck indoors at work all the time and don’t get regular access to the sun. If you’re interested in trying out supplements like Vitamin D and other sports nutrition supplements, consider subscribing to PrettyFit. It’s an awesome way to discover new products, save money and make health and fitness fun.


  1. Webb AR, et al. Influence of season and latitude on the cutaneous synthesis of vitamin D3: exposure to winter sunlight in Boston and Edmonton will not promote vitamin D3 synthesis in human skin. J Clin Endocrinol Metab. 1988 Aug;67(2):373-8. PubMed PMID: 2839537.
  2. Morton JP, et al. Seasonal variation in vitamin D status in professional soccer players of the English Premier League. Appl Physiol Nutr Metab. 2012 Aug;37(4):798-802. doi: 10.1139/h2012-037. Epub 2012 May 4. PubMed PMID: 22554144.
  3. Galan F, et al. Serum 25-hydroxyvitamin D in early autumn to ensure vitamin D sufficiency in mid-winter in professional football players. Clin Nutr. 2012 Feb;31(1):132-6. doi: 10.1016/j.clnu.2011.07.008. Epub 2011 Aug 16. PubMed PMID: 21843910.
  4. Coney P, et al. Determination of vitamin D in relation to body mass index and race in a defined population of black and white women. Int J Gynaecol Obstet. 2012 Oct;119(1):21-5. doi: 10.1016/j.ijgo.2012.05.024. Epub 2012 Jul 18. PubMed PMID: 22818533; PubMed Central PMCID: PMC3438362.
  5. Fiscella K, et al. Vitamin D, race, and cardiovascular mortality: findings from a national US sample. Ann Fam Med. 2010 Jan-Feb;8(1):11-8. doi: 10.1370/afm.1035. PubMed PMID: 20065273; PubMed Central PMCID: PMC2807382.
  6. Cannell JJ, et al. Athletic performance and vitamin D. Med Sci Sports Exerc. 2009 May;41(5):1102-10. doi: 10.1249/MSS.0b013e3181930c2b. Review. PubMed PMID: 19346976.
  7. Ceglia L, et al. A randomized study on the effect of vitamin D₃ supplementation on skeletal muscle morphology and vitamin D receptor concentration in older women. J Clin Endocrinol Metab. 2013 Dec;98(12):E1927-35. doi: 10.1210/jc.2013-2820. Epub 2013 Oct 9. PubMed PMID: 24108316
  8. Cannell JJ, et al. Athletic performance and vitamin D. Med Sci Sports Exerc. 2009 May;41(5):1102-10. doi: 10.1249/MSS.0b013e3181930c2b. Review. PubMed PMID: 19346976.
  9. Ruohola JP, et al. Association between serum 25(OH)D concentrations and bone stress fractures in Finnish young men. J Bone Miner Res. 2006 Sep;21(9):1483-8. PubMed PMID: 16939407.
  10. Burgi AA, et al. High serum 25-hydroxyvitamin D is associated with a low incidence of stress fractures. J Bone Miner Res. 2011 Oct;26(10):2371-7. doi: 10.1002/jbmr.451. PubMed PMID: 21698667.

Evan Clark

Evan Clark is a former wildland firefighter turned fitness pro (NSCA CPT). Though he loves his heavy squat and deadlift sessions, he believes that health and fitness extend well beyond the gym and that fitness should be a tool to promote mental health and lifestyle balance.

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