A 16-week randomized clinical trial of 2000 international units daily vitamin D3 supplementation in black youth: 25-hydroxyvitamin D, adiposity, and arterial stiffness.
J Clin Endocrinol Metab. 2010 Oct;95(10):4584-91. Epub 2010 Jul 21. PMID: 20660028
Georgia Prevention Institute, Department of Pediatrics, Medical College of Georgia, Augusta, Georgia 30912, USA. email@example.com
CONTEXT: Vitamin D insufficiency/deficiency is commonly observed in black youth.
OBJECTIVE: The aim was to determine 25-hydroxyvitamin D [25(OH)D] in response to 2000 IU vitamin D supplementation over time; to evaluate the relation between 25(OH)D concentrations and total body fat mass by dual-energy x-ray absorptiometry; and to determine whether vitamin D supplementation improves arterial stiffness measured by pulse wave velocity (PWV).
DESIGN: We conducted a randomized, blinded, controlled clinical trial.
SETTING AND PARTICIPANTS: Forty-nine normotensive black boys and girls, aged 16.3± 1.4 yr, were randomly assigned to either the control group (400 IU/d; n = 24) or the experimental group (2000 IU/d; n = 25).
RESULTS: Plasma 25(OH)D values at baseline and at 4, 8, and 16 wk were 34.0± 10.6, 44.9 ± 9.4, 51.2 ± 11.1, and 59.8 ± 18.2 nmol/liter, respectively, for the control group; and 33.1 ± 8.7, 55.0 ± 11.8, 70.9 ± 22.0, and 85.7 ± 30.1 nmol/liter, respectively, for the experimental group. The experimental group vs. the control group reached significantly higher 25(OH)Dconcentrations at 8 and 16 wk, respectively. Partial correlation analyses indicated that total body fat mass at baseline was significantly and inversely associated with 25(OH)D concentrations in response to the 2000-IU supplement across time. Furthermore, carotid-femoral PWV increased from baseline(5.38 ± 0.53 m/sec) to posttest (5.71 ± 0.75 m/sec) in the control group (P = 0.016), whereas in the experimental group carotid-femoral PWV decreased from baseline (5.41 ± 0.73 m/sec) to posttest (5.33 ± 0.79 m/sec) (P = 0.031).
CONCLUSION: Daily 2000 IU vitamin D supplementation may be effective in optimizing vitamin D status and counteracting the progression of aortic stiffness in black youth. Plasma 25(OH)D concentrations in response to the 2000 IU/d supplementation are negatively modulated by adiposity.