Int J Sport Nutr Exerc Metab. 2013 Mar 26.
Pamela J. Magee 1, L. Kirsty Pourshahidi 1, Julie M.W. Wallace 1, John Cleary 2, 3, Joe Conway 4, Edward Harney 5 and Sharon M. Madigan 2, 3
- 1 Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, Northern Ireland, 2 High Performance Unit, National Boxing Stadium, Dublin,Ireland,
- 3 Irish Institute of Sport, Sports Campus Ireland, Abbottstown, Dublin Ireland,
- 4 Paralympics Ireland, Sport HQ, Clondalkin, Dublin 12
- 5 Down County Board, Castlewellan, Northern Ireland.
BACKGROUND: A high prevalence of vitamin D insufficiency/deficiency is evident among athletes worldwide, which may impact on health and training ability.
This observational study investigated the vitamin D status of elite Irish athletes and determined the effect of wintertime supplementation on status.
METHODS: Serum 25-hydroxyvitamin D (25(OH)D), calcium and plasma parathyroid hormone were analyzed in elite athletes (17 boxers, 33 paralympians and 34 Gaelic Athletic Association (GAA) players) in November 2010 (boxers and paralympians) or March 2011 (GAA players). A sub-set of boxers and paralympians (n=27) were supplemented with vitamin D3 during the winter months with either 5000 IU vitamin D3/d for 10-12 weeks or 50,000 IU on one or two occasions. Biochemical analysis was repeated following supplementation.
RESULTS: Median 25(OH)D of all athletes at baseline was 48.4 nmol/L.
Vitamin D insufficiency/deficiency (serum 25(OH)D < 50 nmol/L) was particularly evident among GAA players (94%) due to month of sampling.
Wintertime supplementation (all doses) significantly increased 25(OH)D (median 62.8 nmol/L at baseline vs. 71.1 nmol/L in April/May; p = 0.001) and corrected any insufficiencies/deficiencies in this sub-set of athletes. In contrast, 25(OH)D significantly decreased in those that did not receive a vitamin D supplement, with 74% of athletes classed as vitamin D insufficient/deficient after winter, compared to only 35% at baseline.
CONCLUSIONS: This study has highlighted a high prevalence of vitamin D insufficiency/deficiency among elite Irish athletes and demonstrated that wintertime vitamin D3 supplementation is an appropriate regime to ensure vitamin D sufficiency in athletes during winter and early spring.
|Vitamin D||Feb / March||April / May|
|5,000 IU||25 ng/ml||28 ng/ml|
|No IU||35% were < 20 ng||74% were < 20 ng|
- Dark Skin
- Poor health
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- Overview How Much vitamin D
- Is 50 ng of vitamin D too high, just right, or not enough
- Vitamin D Recommendations around the world - IU and ng
- 5000 IU vitamin D helped UK professional athletes in the winter – Oct 2012
- Muscle fatigue reduced with 10,000 IU of vitamin D – March 2013
- Top UK soccer coach installed vitamin D booths in his club – Dec 2012
- Athletes need at least 40 ng of vitamin D – literature review Oct 2012
Overview Sports and vitamin D has the following summary
Athletes are helped by vitamin D by:
- Faster reaction time
- Far fewer colds/flus during the winter
- Less sore/tired after a workout
- Fewer micro-cracks and broken bones
- Bones which do break heal much more quickly
- Increased VO2 and exercise endurance Feb 2011
- Indoor athletes especially need vitamin D
- Professional indoor athletes are starting to supplement with vitamin D or use vitamin D beds
- Olympic athletes have used UV/vitamin D since the 1930's
- The biggest gain from the use of vitamin D is by those who exercise less than 2 hours per day.
- Reduced muscle fatigue with 10,000 IU vitamin D daily
- Muscle strength improved when vitamin D added: 3 Meta-analysis
- Sports and Vitamin D category