The effect of body composition and BMI on 25(OH)D response in vitamin D-supplemented athletes |
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| Authors: | Evan P Cassity Maja Redzic Cassidy R Teager |
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| Institution: | 1. Division of Pulmonary, Critical Care and Sleep Medicine, University of Kentucky, Lexington, KY, USA;2. Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA;3. College of Health Sciences, University of Kentucky, Lexington, KY, USA |
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| Abstract: | Fat mass is inversely associated with vitamin D status, and athletes with the most adipose tissue may have the greatest risk for insufficient (25(OH)D 20–32?ng?mL?1) or deficient (25(OH)D??1) status. The effects of fat and lean mass on 25(OH)D change in response to vitamin D supplementation have yet to be elucidated in athletes. In addition, vitamin D has a known role in bone health yet a link between short-term changes in 25(OH)D and bone turnover in indoor athletes have not yet been described. Thirty-two collegiate swimmers and divers (19 male, 13 female; 19 (1) years) participated in a 6-month randomized controlled trial and consumed either 4000?IU?d?1 of vitamin D3 (n?=?19) or placebo (PLA; n?=?13). Anthropometry and blood collection of 25(OH)D, bone-specific alkaline phosphatase (B-ALP) and N-terminal telopeptide (NTx) occurred at three time points. Dual-energy X-ray absorptiometry measured body composition analysis at baseline and endpoint. In the vitamin D group, BMI was negatively correlated with 6-month 25(OH)D change (R?=??0.496; P?=?.03) and a stronger predictor of 25(OH)D change (P?=?.04) than ultraviolet B exposure and fat mass change. Athletes in the high bone turnover group showed significantly greater losses of 25(OH)D over 6-months compared to athletes in the low bone turnover group (P?=?.03). These results suggest athletes within the normal BMI category experience a diminished response to 4000?IU?d?1 of vitamin D3 supplementation, and periods of high bone turnover may be an additional risk factor for developing compromised vitamin D status in athletes. |
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| Keywords: | Bone turnover fat mass BMI swimmer |
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