European Journal of Sport Science, DOI:10.1080/17461391.2014.944223, online: 18 Aug 2014
Daniel J. Owensa, William D. Fraserb & Graeme L. Closea*
Interest in Vitamin D has risen considerably recently with many athletes now advised to take daily vitamin D supplements.
The reason for this interest is partly not only attributed to the resurgence of the Vitamin D-deficient disease rickets but also due to the discovery of a Vitamin D receptor in many tissues suggesting a more global role for Vitamin D than previously considered. Unlike the other vitamins that are obtained through the diet, Vitamin D is unique since endogenous synthesis following ultraviolet B (UVB) exposure is the predominant route of entry into systemic circulation. Moreover, Vitamin D could be better classed as a seco-steroid, given that its structure is similar to that of a steroid, and its production is derived from a cholesterol precursor (7-dehydrocholesteol) in the skin. The classification of Vitamin D status is currently subject to considerable debate with many authors opposing governing body recommendations.
Regardless of the suggested optimal concentration, there is now growing evidence to suggest that many athletes are in fact Vitamin D deficient, especially in the winter months largely as a consequence of inadequate sun exposure, combined with poor dietary practices, although the consequences of such deficiencies are still unclear in athletic populations.
- Impaired muscle function and
- reduced regenerative capacity,
- impaired immune function,
- poor bone health
- and even impaired cardiovascular function
have all been associated with low Vitamin D in athletes, however, to date, the majority of studies on Vitamin D have described associations and much more research is now needed examining causation.
- Vitamin D supplementation improves muscle strength in healthy adults – meta-analysis of 6 RCT Aug 2014
- Dark skinned NCAA basketball players were 15X more likely to have low vitamin D – Feb 2014
- The Big D (an editorial in American Journal of Sports Medicine) – Jan 2014
- Muscle improved by increasing vitamin D if previously less than 24 ng – June 2013 Proof
- Fewer injuries and higher ballet jumps with 2,000 IU of vitamin D – April 2013 Proof
- Muscle fatigue reduced with 10,000 IU of vitamin D – March 2013 Proof
- 5,000 IU vitamin D helped UK professional athletes in the winter – Oct 2012 Proof
- Overview Sports and vitamin D has the following summary
Athletes are helped by vitamin D by:
- Faster reaction time
- Far fewer colds/flus during the winter
- Less sore/tired after a workout
- Fewer micro-cracks and broken bones
- Bones which do break heal much more quickly
- Increased VO2 and exercise endurance Feb 2011
- Indoor athletes especially need vitamin D
- Professional indoor athletes are starting to supplement with vitamin D or use vitamin D beds
- Olympic athletes have used UV/vitamin D since the 1930's
- The biggest gain from the use of vitamin D is by those who exercise less than 2 hours per day.
- Reduced muscle fatigue with 10,000 IU vitamin D daily
- Muscle strength improved when vitamin D added: 3 Meta-analysis
- Sports and Vitamin D category