Effects of Seasonal Vitamin D3 Supplementation on Strength, Power, and Body Composition in College Swimmers
Int J Sport Nutr Exerc Metab, 1-9 2020 Feb 4, DOI: 10.1123/ijsnem.2019-0250
Michelle S Rockwell 1, Madlyn I Frisard 1, Janet W Rankin 1, Jennifer S Zabinsky 1, Ryan P Mcmillan 1, Wen You 1, Kevin P Davy 1, Matthew W Hulver 1
- NCAA trainers are getting on board the Vitamin D train (40-50 ng)– Nov 2019
- Vitamin D is not considered to be doping
- Athletes helped by weekly 50,000 IU Vitamin D – RCT Aug 2019
- 4,000 IU of Vitamin D is OK - 19 organizations agree - 2018
- Need 40 to 60 ng of Vitamin D – 48 scientists call for action – 2015
Indoor Athletes have lower Vitamin D levels
- NFL team less likely to cut players with high levels of vitamin D – Feb 2015
- NHL discovers Vitamin D – their ideal is 40-120 ng – 2016
- Every single Taekwondo (indoor) Korean teen had low Vitamin D – Sept 2019
- Dark skinned NCAA basketball players were 15X more likely to have low vitamin D – Feb 2014
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
- Reduced Concussions
See also: Sports and Vitamin D category
Sports category in VitaminDWiki starts with
228 items in Sports category
Sports benefits from up to 50 ng (click on chart for details)
Overview Sports and vitamin D Concussions
Military Muscle Overview Fractures and vitamin D
Vitamin D supplementation increases strength of lower muscles – Meta-analysis April 2019
Athletes helped by weekly 50,000 IU Vitamin D – RCT Aug 2019
Many Foot and ankle problems are treated by Vitamin D – review of 35 studies – Sept 2019
Vitamin D provides faster recovery after muscle overuse – April 2013
NCAA trainers are getting on board the Vitamin D train (40-50 ng)– Nov 2019
The Meta-analysis of Sports and Vitamin D are listed here:
- Vitamin D trials by military – all 4 found benefit – review Sept 2019
- Vitamin D supplementation increases strength of lower muscles – Meta-analysis April 2019
- Resistance exercise combined with Vitamin D is great for seniors – meta-analysis July 2017
- Stress fractures in basic training associated with 2.5 ng less vitamin D – meta-analysis Nov 2014
- Vitamin D supplementation improves muscle strength in healthy adults – meta-analysis of 6 RCT Aug 2014
- Vitamin D supplementation help muscles of seniors who are vitamin D deficient – meta-analysis July 2014
- Sports benefits from up to 50 ng of Vitamin – meta-analysis - Nov 2012
- Elderly lower limb muscle strength improved with Vitamin D supplementation - Meta-analysis Oct 2013
- Vitamin D improves muscle strength if deficient – meta-analysis - Oct 2010
The purpose of this study was to evaluate the impact of fall season vitamin D3 supplementation on strength/power, body composition, and anabolic hormones in swimmers with optimal vitamin D status at summer's end. Male and female National Collegiate Athletic Association Division I swimmers (N = 19) with optimal 25-hydroxyvitamin D [25(OH)D] randomly received 5,000 IU of vitamin D3 (VITD) or placebo (PLA) daily for 12 weeks while participating in swimming and strength and conditioning training (August-November). Before and after the intervention, the participants underwent blood sampling for analysis of serum 25(OH)D, parathyroid hormone, total testosterone, free testosterone, sex hormone-binding globulin, and insulin-like growth factor 1, dual-energy X-ray absorptiometry, and strength/power testing (bench press, squat, dead lift, standing broad jump, vertical jump, and dips and pull-ups). Sex was used as a covariate for analyses.
- The 25(OH)D was decreased by 44% in PLA (p < .05) and increased by 8% in VITD over the 12 weeks.
- Fat-free mass increased in VITD (56.4-59.1 kg; p < .05), but not PLA (59.4-59.7 kg; p < .01).
- Appears that added 2.7 kg of muscle if take Vitamin D, but only added 0.3 kg if placebo
- Significant Group × Time interaction effects were observed for dead lift (F = 21.577, p < .01) and vertical jump (F = 11.219, p < .01), but no other strength/power tests.
- Total testosterone decreased similarly in both groups, but free testosterone decreased and sex hormone-binding globulin increased only in PLA (p < .01).
- There were no group differences or changes in insulin-like growth factor 1 with the intervention.
The findings suggest that vitamin D supplementation is an efficacious strategy to maintain 25(OH)D during the fall season training and to enhance some aspects of strength/power and fat-free mass in swimmers. Further research on the relationship between vitamin D and anabolic hormones is needed.
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