Background: Obese adolescents are at a greater risk for vitamin D deficiency because the vitamin is thought to be sequestered by excess adipose...
» More
Background: Obese adolescents are at a greater risk for vitamin D deficiency because the vitamin is thought to be sequestered by excess adipose tissue. Poor vitamin D status has been associated with a higher prevalence of the metabolic syndrome and/or type 2 diabetes in both adults and adolescents.
Objective: To determine in obese adolescents the efficacy and safety of 4000 IU/day of vitamin D3; and if subsequent increased circulating concentrations of 25 hydroxyvitamin D [(25(OH)D] are associated with improved markers of insulin sensitivity/resistance and reduced inflammation.
Design: Obese adolescent patients (n=29; age=14.2±2.6 years; BMI=39.2±5.9 kg/m2; 25(OH)D= 19.4±7.3) were recruited from the University of Missouri Adolescent Diabetes and Obesity Clinic and were randomized to receive either vitamin D3 (4000 IU/day) or placebo as part of their standard care. Anthropometrics, inflammatory markers (IL-6, TNF-alpha, c-reactive protein), adipokines (leptin, adiponectin), fasting glucose, fasting insulin, and HOMA-IR were measured at baseline and two follow-up visits (3- and 6-month).
Results: After 6 months, there were no significant differences in BMI, serum inflammatory markers or plasma glucose concentrations between groups. Participants supplemented with vitamin D3 had increases in serum 25(OH)D concentrations (19.5 vs 2.8 ng/mL for placebo; P<0.001), fasting insulin (-6.5 versus +1.2 ?U/mL for placebo; P=0.026), HOMA-IR (-1.363 versus +0.27 for placebo; P=0.033), and leptin to adiponectin ratio (-1.41 versus +0.10 for placebo; P=0.045). Inflammatory markers remained unchanged.
Conclusions: Correcting poor vitamin D status through dietary supplementation may be an effective addition to the standard treatment of obesity and its associated insulin resistance.
