Assessment of Vitamin D Concentration in Non-Supplemented Professional Athletes and Healthy Adults During the Winter Months in the UK: Implications for Skeletal Muscle Function

J Sports Sci. 2013;31(4):344-53. doi: 10.1080/02640414.2012.733822. Epub 2012 Oct 22.

Abstract

The current study implemented a two-part design to (1) assess the vitamin D concentration of a large cohort of non-vitamin D supplemented UK-based athletes and 30 age-matched healthy non-athletes and (2) to examine the effects of 5000 IU · day(-1) vitamin D(3) supplementation for 8-weeks on musculoskeletal performance in a placebo controlled trial. Vitamin D concentration was determined as severely deficient if serum 25(OH)D < 12.5 nmol · l(-1), deficient 12.5-30 nmol · l(-1) and inadequate 30-50 nmol · l(-1). We demonstrate that 62% of the athletes (38/61) and 73% of the controls (22/30) exhibited serum total 25(OH)D < 50 nmol · l(-1). Additionally, vitamin D supplementation increased serum total 25(OH)D from baseline (mean ± SD = 29 ± 25 to 103 ± 25 nmol · l(-1), P = 0.0028), whereas the placebo showed no significant change (53 ± 29 to 74 ± 24 nmol · l(-1), P = 0.12). There was a significant increase in 10 m sprint times (P = 0.008) and vertical-jump (P = 0.008) in the vitamin D group whereas the placebo showed no change (P = 0.587 and P = 0.204 respectively). The current data supports previous findings that athletes living at Northerly latitudes (UK = 53° N) exhibit inadequate vitamin D concentrations (<50 nmol · l(-1)). Additionally the data suggests that inadequate vitamin D concentration is detrimental to musculoskeletal performance in athletes. Future studies using larger athletic groups are now warranted.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Athletic Performance / physiology*
  • Case-Control Studies
  • Dietary Supplements*
  • Humans
  • Male
  • Movement / physiology
  • Muscle, Skeletal / physiology*
  • Physical Exertion / drug effects
  • Physical Exertion / physiology
  • Prevalence
  • Running / physiology
  • Seasons*
  • Sports / physiology*
  • United Kingdom
  • Vitamin D / administration & dosage
  • Vitamin D / analogs & derivatives
  • Vitamin D / blood
  • Vitamin D / therapeutic use*
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / complications*
  • Vitamin D Deficiency / epidemiology
  • Vitamin D Deficiency / prevention & control
  • Young Adult

Substances

  • Vitamin D
  • 25-hydroxyvitamin D