Vitamin D3 supplementation using an oral spray solution resolves deficiency but has no effect on VO2 max in Gaelic footballers: results from a randomised, double-blind, placebo-controlled trial

Joshua J. Todd, Emeir M McSorley, L. Kirsty Pourshahidi, Sharon M. Madigan, Eamon Laird, Martin Healy, Pamela Magee

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Purpose 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 D3 supplementation [3000 IU (75 µg) daily for 12 weeks, via an oral spray solution] on VO2 max 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 VO2 max (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 D3 successfully resolved deficiency but did not have any significant effect on VO2 max, skeletal muscle or lung function.
Original languageEnglish
Pages (from-to)1577-1587
Number of pages11
JournalEuropean Journal of Nutrition
Issue number4
Early online date25 Mar 2016
Publication statusPublished - 30 Jun 2017



  • Athletes
  • Football
  • Randomised controlled trial
  • VO2 max
  • Vitamin D

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