vitamin d
VITAMIN D Why do we need vitamin D? Vitamin D is unlike any other vitamin. It is converted into an active hormone in the body and affects how most cells grow and perform. Vitamin D is important for: • calcium absorption from the gut • optimizing bone health • improving muscle strength and balance • maintaining a healthy immune system
Where does vitamin D come from?
Vitamin D is called the sunshine vitamin because it is produced naturally in your skin when the skin is exposed to sunlight. It is also found supplements and in a small number of foods. Sunlight: The action of sunlight (UVB rays) on the skin forms Vitamin D. This is dependent on a number of factors including time of day, season, cloud cover and your skin pigmentation, sunscreen use and level of body fat. Supplements: Klean Vitamin D3 preferred, also Jamieson 1,000IU D3. Food: Wild oily fish, cod liver oil, animal fats, eggs yolks, and fortified foods such as milk and cereals contain a small amount of vitamin D, but the levels are not considered high enough to meet your daily requirements.
You may be at risk of vitamin D deficiency if you: • • • • • • •
train predominantly indoors wear sunscreen 15 SPF or greater daily have dark skin train fully covered e.g. skiers live/train only in Canada in the winter have very low or very high body fat levels have a spinal cord injury
Potential performance benefits? Sufficient vitamin D levels are needed to maintain bone health, help prevent muscle/soft-tissue injuries and fight off upper respiratory infections that may have been caused by high volume training at high intensities. Sufficient Vitamin D levels may also enhance the ability of muscle to make quick, explosive movements and may positively affect velocity and jump height.
A SPORTS NUTRITION PUBLICATION © THE UBC DEPARTMENT OF ATHLETICS AND RECREATION, JULY 2017
Maintain sufficient Vitamin D by: Safe sun exposure During May to September expose your legs, arms, face and hands to sun for 3 – 8 minutes to produce about 1,000IU of vitamin D2 or soak up the sun for 15 – 30 minutes to maximize vitamin D production in the skin (10,000 – 20, 000 IU). Be sure to avoid burning your skin due to the increased risks associated with sun damage.
From the end of September to the beginning of April you are unable to make vitamin D in your skin when living at latitudes higher than 35-37 due to the low angle of the sun. Victoria/Vancouver are at latitude 43 and 44 respectively. This means that supplemental vitamin D is essential in winter months.
Supplementation
3, 4, 6
Based on a recent publications on Vitamin D in the athletic population , 2,000IU of Vitamin D3 per day is recommended from September – beginning of April. Vitamin D is a fat soluble vitamin, meaning it is stored in your fat cells, so if you miss a day, you can take a double dose the following day. Emerging research indicates that lower doses are likely more effective at increasing vitamin D levels and that gradual is more favourable 6 than raplidly stopping supplementation . Vitamin D3 supplementats are absorbed with a meal that contains 1 fat . If you have dark coloured skin you make less vitamin D from the sun’s rays and are advised to take 2,000 IU 5 vitamin D3 year round .
Are there any side effects of health risks? No adverse side effects to moderate dose Vitamin D have been reported.
**Please speak with your Sports Dietitian for further information**
1. 2. 3. 4. 5. 6.
Osteoporosis Canada, Vitamin D: An Important Nutrient That Protects You Against Falls and Fractures Retrieved from http://www.osteoporosis.ca/osteoporosis-and-you/nutrition/vitamin-d/ Terushkin et al. Estimated Equivalency Of Vitamin D Production From Natural Skin Exposure Versus Oral Vitamin D Supplementation Across Seasons At 2 US latitudes. Journal of the American Academy of Dermatology,2009; 62: 6: 929 Shuler FD, Wingate MK, Moore GH, Giangarra C. Sports health benefits of vitamin D. Sports Health. 2012; 4 (6): 496–501. Oga, D. and K. Pritchett. "Vitamin D and the Athlete: Risks, Recommendations, and Benefits." Nutrients 5, no. 6 (2013): 1856-68. Hall et al. Vitamin D intake needed to maintain target serum 25-hydroxyvitamin D concentrations in participants with low sun exposure and dark skin pigmentation. Journal of Nutrition, 2010; 140: 542–550 Owens D.J., Tang J.C.Y, Bradley W. J, Sparks S.A., Fraser W.D., Morton J.P., Close G.L. (2017) Efficacy of High Dose Vitamin D Supplements for Elite Athletes. Medicine and Science in Sport and Exercise 49(2):349-356
A SPORTS NUTRITION PUBLICATION © THE UBC DEPARTMENT OF ATHLETICS AND RECREATION, JULY 2017
