Introducing the 'sunshine' vitamin!

Canadian winters mean short days and bundling up against the cold, so getting the required amount of sunlight for absorbing Vitamin D can be difficult. Vitamin D (sometimes called the 'sunshine vitamin') is unique in that it requires the skin to be exposed to ultraviolet-B radiation for optimal absorption. Because it is present in very few foods and many people use sunscreen to protect themselves from the harmful effects of UV rays, it has become common for athletes to use supplements to obtain vitamin D.

Why should athletes consider vitamin D?

Vitamin D functions to maintain normal levels of calcium and phosphorus in the blood, as well as aiding in the absorption of calcium to form and maintain strong bones. Research suggests that it may be important for prevention of osteoporosis, hypertension, inflammation, asthma, and seasonal affective disorder.

Factors that may contribute to vitamin D deficiency include skin pigmentation, early or late day training, indoor training, geographic location and sunscreen use. Athletes that may be at higher risk are those that spend the most time indoors; gymnasts, ballet dancers, figure skaters, and wrestlers.

While vitamin D can be obtained in the diet, it would be difficult to consume the amount food you would need for optimal performance. For example, it would take six cups of orange juice or 14 eggs to get the recommended amount.

Foods that contain Vitamin D:

• Fatty fish (tuna, salmon, swordfish) and fish liver oils like cod liver
• Beef, egg yolks and some cheeses contain small amounts
• Fortified foods like milk, orange juice and cereal, although they include small amounts

A recent survey done by Statistics Canada found that 32% of the Canadian population have vitamin D levels that are below recommendations. Adding vitamin D supplements to your diet carries a low risk for side effects, however it's recommended that you talk to your coach and/or health professional first.

References from the SIRC Collection:

1. Asp K. Running on D. Runner's World. December 2009;44(12):36-37.
2. Close G, Fraser B. Vitamin D supplementation for athletes: Too much of a good thing?. Sport & Exercise Scientist. September 2012;(33):24-25.
3. HAMILTON B, CHALABI H. VITAMIN D: AN UPDATE FOR THE SPORTS MEDICINE PRACTITIONER. Sportex Medicine. January 2010;(43):11-16.
4. Larson-Meyer D, Willis K. Vitamin D and Athletes. Current Sports Medicine Reports (American College Of Sports Medicine). July 2010;9(4):220-226.
5. Shuler F, Wingate M, Moore G, Giangarra C. Sports Health Benefits of Vitamin D. Sports Health: A Multidisciplinary Approach. November 2012;4(6):496-501.
6. The Vegetarian Athlete. Running & Fitnews. May 2009;27(3):10-12.
7. Willis K, Peterson N, Larson-Meyer D. Should We Be Concerned About the Vitamin D Status of Athletes?. International Journal Of Sport Nutrition & Exercise Metabolism. April 2008;18(2):204-224.