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.
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.
Muscle Metabolism and Physiology Research group, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK. G.L.Close@ljmu.ac.uk
G L
GL
Close
J
J
Russell
J N
JN
Cobley
D J
DJ
Owens
G
G
Wilson
W
W
Gregson
W D
WD
Fraser
J P
JP
Morton
D000293:Adolescent; D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D016022:Case-Control Studies; D019587:Dietary Supplements; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000187:drug effects / Q000502:physiology; D015995:Prevalence; D012420:Running / Q000502:physiology; D012621:Seasons; D013177:Sports / Q000502:physiology*; D006113:United Kingdom; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications* / Q000453:epidemiology / Q000517:prevention & control; D055815:Young Adult
D014807:Vitamin D; C104450:25-hydroxyvitamin D