Collegiate Swimmers getting 4000 IU of vitamin D had fewer injuries – March 2013

The Effects of Season-Long Vitamin D Supplementation on Collegiate Swimmers and Divers.

Int J Sport Nutr Exerc Metab. 2013 Mar 8.
Lewis RM, Redzic M, Thomas DT.
Division of Clinical Nutrition, University of Kentucky, Lexington, KY.

The purpose of this 6-month randomized placebo controlled trial was to determine the effect of season-long (September-March) vitamin D supplementation on changes in vitamin D status (measured as 25(OH)D), body composition, inflammation, frequency of illness and injury. Forty-five male and female athletes were randomized to 4000IU vitamin D (n=23) or placebo (n=22). 25(OH)D, bone turnover markers (NTx and BSAP), and inflammatory cytokines (TNF-alpha, IL-6, and IL1-β) were measured at baseline, midpoint, and endpoint. Body composition was assessed by DXA and injury and illness data were collected.

All athletes had sufficient 25(OH)D (>32ng/mL) at baseline (mean: 57ng/mL). At midpoint and endpoint, 13% and 16% of the total sample had 25(OH)D <32ng/mL, respectively. 25(OH)D was not positively correlated with bone mineral density (BMD) in the total body, proximal dual femur, or lumbar spine. In men, total body (p=0.04) and trunk (p=0.04) mineral-free lean mass (MFL) were positively correlated with 25(OH)D.
In women, right femoral neck BMD (p=0.02) was positively correlated with 25(OH)D. 25(OH)D did not correlate with changes in bone turnover markers or inflammatory cytokines.

Illness (n=1) and injury (n=13) were not related to 25(OH)D; however, 77% of injuries coincided with decreases in 25(OH)D. Our data suggests that 4000IU vitamin D supplementation is an inexpensive intervention that effectively increased 25(OH)D, which was positively correlated to bone measures in the proximal dual femur and MFL. Future studies with larger sample sizes and improved supplement compliance are needed to expand our understanding of the effects of vitamin D supplementation in athletes.

PMID: 23475128

---

Wow: At the start of the trial they all had high levels of vitamin D.
This study probably started in the fall, just after the students had been out swimming during the summer
Even starting with a high blood level of vitamin D, adding more vitamin D helped.

See also VitaminDWiki

• Vitamin D Fortification in Finnish Military - stress fracture - 2012.pdf file, not web page
• Half as many fractures for girls with high vitamin D intake – March 2012
• More muscle injuries in NFL players who were low on vitamin D – July 2011
• Perhaps Stress fractures 2X less frequent if 4000 IU of vitamin D – June 2011
• Injury-Prevention with Vitamin D – Feb 2010
• Story – Prevent injuries and speed healing with vitamin D – Jan 2010
• All items in the Sports and D category 282 items
• Nutritional deficiencies of seasoned athletes (vitamin D is 2nd) – Aug 2013
• Elite outdoor athletes had 52 ng of vitamin D – March 2013
• Fewer injuries and higher ballet jumps with 2,000 IU of vitamin D – April 2013
• Some athletes would benefit from more vitamin D – May 2013
• Review of Vitamin D and Physical Performance – May 2013
• Overview Sports and vitamin D which has the following summary
  Athletes are helped by vitamin D by:

1. Faster reaction time
2. Far fewer colds/flus during the winter
3. Less sore/tired after a workout
4. Fewer micro-cracks and broken bones
5. Bones which do break heal much more quickly
6. Increased VO2 and exercise endurance Feb 2011
7. Indoor athletes especially need vitamin D
8. Professional indoor athletes are starting to take vitamin D and/or use UV beds
9. Olympic athletes have used UV/vitamin D since the 1930's
10. The biggest gain from the use of vitamin D is by those who exercise less than 2 hours per day.
11. Reduced muscle fatigue with 10,000 IU vitamin D daily
12. Muscle strength improved when vitamin D added: 3 Meta-analysis
13. Reduced Concussions
    See also: Sports and Vitamin D category 282 items