Safety and efficacy of using high dose (4000 IU daily) vitamin D supplementation to improve the vitamin D status of obese adolescents

The prevalence of vitamin D (vit D) insufficiency in the North American population, particularly adolescents, has been classified as an “epidemic”; and obese adolescents are considered at an even greater risk for deficiency because they tend to store vit D in their fat stores which is not readily mobilized. Moreover, little is known about the safety of exceeding the current UL for vit D (2000 IU) established by the Institute of Medicine in this population. Our objective was to determine the safety and efficacy of supplementing obese adolescents with 4000 IU/day of vit D 3 . Male and female adolescent patients (age=14.3±2.7 years; BMI=41.3±5.1) were recruited from the University of Missouri Adolescent Diabetes and Obesity clinic and were randomized to receive either placebo or 4000 IU/day of vit D 3 for 6 months as part of their standard treatment. The subjects supplemented with vit D 3 had significantly greater increases in serum concentrations of 25‐hydroxyvitamin D (17.0 vs 0.5 ng/ml for the placebo; P <0.001). Serum calcium remained unchanged and within normal limits for both groups (9.2±0.32 and 9.3±0.18 mg/d for placebo and vit D groups, respectively; P =0.742). Conclusions Supplementing obese adolescents with a daily dose 4000 IU vitamin D3 is safe and effective in improving vitamin D status. These findings are consistent with observations in adult populations. Support: J.R. Albert Charitable Foundation, Inc.