Vitamin D sufficiency may enhance athletic performance
Posted Jun 18 2013 4:55pm
The importance of vitamin D for bone health is now well-recognized, and the epidemic of vitamin D insufficiency and deficiency is thought to contribute to a wide range of medical conditions including cancers, mood disorders, autoimmune conditions, cardiovascular disease and more.1 As such, vitamin D sufficiency (25(OH)D greater than 30 ng/ml) is associated with a reduced risk of death from all causes.2,3
In addition to bone, vitamin D receptors are present in almost all cells of the body, including muscle cells. Vitamin D’s primary function is the regulation of calcium transport and metabolism – since calcium transport is an integral part of muscle contraction and relaxation, vitamin D is extremely important for proper muscle function. There is also evidence that achieving vitamin D sufficiency may help to increase muscle mass . In the early 20th century, observations led athletes and trainers to believe that sunlight exposure could enhance athletic performance. Athletic performance has been reported to vary seasonally, peaking in the summer; positive effects of UVB exposure on athletic performance were reported as early as the 1930s. There is now speculation that improved vitamin D status is the reason for these findings.4,5
Previous studies have shown that vitamin D status correlates with muscle function in the elderly, and that vitamin D supplementation improves muscle strength in elderly and/or deficient populations.6-9 New research is beginning to extend these findings to physical performance in athletes . Since there is a high prevalence of vitamin D insufficiency overall, and vitamin d is crucial for bone and muscle function, does vitamin D status affect injury rates or performance in athletes? Two recent studies on professional ballet dancers suggest that it does.
Indoor athletes are likely to have insufficient vitamin D levels.5,10 The first study showed that this was true of ballet dancers in a UK company; on average, their vitamin D status was insufficient (<30 ng/ml) all year round and varied seasonally. In the winter, dancers averaged 14.9 ng/ml (deficient), and in the summer, 23.9 ng/ml (insufficient). The authors also observed a greater occurrence of injuries in the winter months.11 The follow-up study provided vitamin D3 supplements (2000 IU/day) to some of the dancers during the winter, and investigated muscle function and injury rates. In the vitamin D group, there were increases in isometric strength and vertical jump height, plus significantly fewer injuries compared to the control group.12
This is consistent with a previous study of UK athletes, which compared 5000 IU vitamin D for 8 weeks to placebo. The researchers saw increases in sprint times and vertical jump height in the vitamin D group, but not in the placebo group.13
These results suggest that vitamin D’s beneficial effects on bone and muscle physiology can translate into enhanced athletic performance. Achieving sufficient blood vitamin D levels (25(OH)D of 30-45 ng/ml) is crucial for the health of the entire body, not just for preventing osteoporosis .
Image credit: Flickr - TooFarNorth
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