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Vitamin D Has Sports Health Benefits

Vitamin D deficiency is common in athletes. Correcting the deficiency by taking a Vitamin D supplement can produce significant musculoskeletal sports health benefits, a new study1 reports.

Vitamin D facts

  • Vitamin D is a necessary nutrient that must be obtained from the diet when sufficient quantities cannot be synthesized. 
  • The vitamin is primarily produced following skin exposure to ultraviolet B radiation, but such production can be absent or dramatically reduced due to skin coloration (the melanin in the skin of Africans or African Americans block nearly 99% of vitamin D production) and sunblock use (similar decrease after using SPF 15 sunblock).
  •  Indoor activities, pollution, time of day, increasing age, latitude, and seasonal changes all affect vitamin D production through the skin.
  • Vitamin Dis more potent than Vitamin D2 and should be used for supplementation.Vitamin gel caps with Rx symbol
  • The average American diet supplies very little of the 4000 to 5000 IU of vitamin D3 used per day, even in diets with significant amounts of wild-caught fatty fish.
  • The accepted definition of vitamin D sufficiency is 25-hydroxyvitamin D3 (25(OH)D) above 30 ng.ml. 
  • Based on this definition, vitamin D deficiency affects all age groups and demographics:
    • 50-70% of children and adolescents
    • 75% of whites and 90% of African Americans and Latinos
  • Deficiency rates have doubled from 1994 to 2004

Effects sports health & athletic performance

Vitamin D affects:

  • muscle protein synthesis
  • muscle strength
  • muscle size
  • reaction time
  • balance
  • coordination
  • endurance
  • inflammation; and
  • immunity.

Vitamin D deficiency produces:

  • muscle fiber atrophy
  • slow peak muscle contraction
  • prolonged time to muscle relaxation, and 
  • increased risk of chronic musculoskeletal pain.  

Type II, fast-twitch muscles fibers, extremely important in many of the burst activities necessary for peak athletic performance and fall avoidance, are particularly sensitive to the effects of Vitamin D deficiency.  

Vitamin deficiency common in athletes 

There is no known threshold for optimal sports health benefits of vitamin D, but studies show many elite athletes are vitamin D deficient, with incidences of vitamin D deficiency in: 

  • basketball players (up to 94%)
  • gymnasts (83%)
  • football players (81%)
Because seasonal variations are expected (athletes have higher levels in the summer, when they are getting vitamin D from exposure to the sun), so current recommendations are for testing athletes in early autumn.

Benefits of increasing vitamin D 

Musculoskelatal:

Increasing vitamin D levels provides multiple musculoskeletal benefits, including increased:

  • muscle protein synthesis
  • ATP concentration
  • strength
  • jump height
  • jump velocity
  • jump power
  • exercise capacity, and
  • physical performance.

Other benefits

Vitamin D

  • plays an important role in bone health and fracture prevention
  • has immunomodulatory effects, with increased vitamin D levels reducing inflammation, so that, in theory, if athletes increased their levels of vitamin D by supplementation, inflammation would be reduced, and training could be resumed more quickly. 
  • is correlated with reductions in the reported incidence of colds and flu (Vitamin D status in the spring was correlated with frequency of illness in Division I college athletes.  Athletes, especially those injured (stress fractures), musculoskeletal pain, or those with frequent infections, should have vitamin D levels measured and deficiencies corrected. 

Recommendations for athletes

There are no recommended screening guidelines for vitamin D deficiency, which is diagnosed with a simple blood test. 

If an athlete is vitamin D deficient, supplementation protocols require 50,000 IU of vitamin D3 per week for 8 weeks. A steady state level of 25(OH)D is achieved after about 90 days of supplementation.  Once supplementation is completed, retesting is recommended at 3 months. If levels remain too low, repeating the supplementation protocol for another 8 weeks, and retesting is recommended.  


1. Shuler FD, Wingate M, Moore GH, Giangarra G. Sports Health Benefits of Vitamin D.  Sports Health: A Multidisciplinary Approach. 2012;20(10). DOI:1177/1941738112461621 (published online October 2, 2012)(accessed October 8, 2012). 

Posted October 9, 2012 

 


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