title: Vitamin D3supplementation using an oral spray solution resolves deficiency but has no effect on VO2max in Gaelic footballers: results from a randomised, double-blind, placebo-controlled trial.
abstract: OBJECTIVE
  Vitamin D inadequacy is a global health concern in athletes as well as the general population. Whilst the role of vitamin D in skeletal health is well defined, there remains uncertainty over whether vitamin D supplementation has an added benefit beyond bone health.
  
  
  METHODS
  This randomised placebo-controlled trial in healthy male and female Gaelic footballers (n = 42) investigated the effect of vitamin D3supplementation [3000 IU (75 µg) daily for 12 weeks, via an oral spray solution] on VO2max which was the primary outcome measure. Secondary outcomes included skeletal muscle and lung function.
  
  
  RESULTS
  Supplementation significantly increased total 25-hydroxyvitamin D concentrations compared to the placebo group (mean ± SD change from baseline, 36.31 ± 32.34 vs. 6.11 ± 23.93 nmol/L, respectively; P = 0.006). At baseline, 50 and 22 % of footballers presented with vitamin D insufficiency (31-49 nmol/L) and deficiency (<30 nmol/L), respectively. Total 25-hydroxyvitamin D concentration did not significantly correlate with any measure of physical performance. Analysis of covariance (ANCOVA) models demonstrated that vitamin D supplementation over 12 weeks had no significant effect on VO2max (P = 0.375), vertical jump height (P = 0.797), left and right handgrip strength (P = 0.146 and P = 0.266, respectively), forced vital capacity (P = 0.573) or forced expiratory volume at 1 s (P = 0.665), after adjusting for confounders. The high prevalence of vitamin D inadequacy observed in this cohort of collegiate Gaelic footballers supports the need for vitamin D supplementation during wintertime to avoid being at risk of poor bone health.
  
  
  CONCLUSIONS
  Twelve-week daily supplementation with 3000 IU (75 µg) vitamin D3successfully resolved deficiency but did not have any significant effect on VO2max, skeletal muscle or lung function.
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, UK.
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Todd
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, UK.
authors.forename: Emeir M
authors.initials: EM
authors.lastname: McSorley
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, UK.
authors.forename: L Kirsty
authors.initials: LK
authors.lastname: Pourshahidi
authors.affiliation: Irish Institute of Sport, Sports Campus Ireland, Abbotstown, Dublin 15, UK.
authors.forename: Sharon M
authors.initials: SM
authors.lastname: Madigan
authors.affiliation: Institute of Molecular Medicine, Trinity College, Dublin, UK.
authors.forename: Eamon
authors.initials: E
authors.lastname: Laird
authors.affiliation: Department of Medicine, Trinity Centre for Health Science St. James's Hospital, Dublin, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Healy
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, UK. pj.magee@ulster.ac.uk.
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Magee
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D056352:Athletes; D001823:Body Composition; D002118:Calcium / Q000097:blood; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000097:blood; D003404:Creatinine / Q000097:blood; D019587:Dietary Supplements; D004311:Double-Blind Method; D015444:Exercise; D005260:Female; D005538:Football; D018737:Hand Strength; D006801:Humans; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D015596:Nutrition Assessment; D058993:Oral Sprays; D010101:Oxygen Consumption; D010349:Patient Compliance; D064133:Sports Nutritional Physiological Phenomena; D016896:Treatment Outcome; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy*; D055815:Young Adult
chemical_list: D058993:Oral Sprays; D002762:Cholecalciferol; D003404:Creatinine; D002118:Calcium
keywords: Athletes; Football; Randomised controlled trial; VO2 max; Vitamin D