June 17, 2013 – According to the recent results of a prospective, double-blind, randomized trial, supplementation with 400 IU or 2000 IU of vitamin D3 did not alter cardiometabolic disease (CMD) risk factors in obese adolescents, although it did produce a modest increase in serum levels of 25 hydroxy-vitamin D [25(OH)D].

Asma Javed, MD of the Mayo Clinic in Rochester and colleagues revealed their findings at ENDO 2013: The Endocrine Society’s 95^th Annual Meeting and Expo in San Francisco on June 17, 2013.

According to the researchers, vitamin D deficiency has been found in up to 80% of obese children. An association has been shown observationally between vitamin D and low HDL, increased glucose, and insulin resistance. There is currently no evidence regarding response in lipid levels and cardiometabolic risk factors to vitamin D supplementation; the authors sought to evaluate these effects with two different doses of vitamin D supplementation in obese adolescents.

For this study, 12-18 year old obese adolescents (BMI > 95^th percentile) were randomized to receive either 2000 IU vitamin D3 daily (n = 23) or 400 IU vitamin D3 daily for 12 weeks. Laboratory values were obtained at baseline and at 12 weeks. These included serum 25(OH)D, fasting plasma glucose, insulin, total cholesterol, high density cholesterol, triglycerides, high sensitivity C-reactive protein (hsCRP), interleukin- 6 (IL-6), total (T) adiponectin, high molecular weight (HMW) adiponectin and retinol binding protein 4 (RBP4).

Results showed a median serum 25(OH)D level increase of 5 ng/ml (p=0.039) in subjects who received 2000 IU vitamin D3 per day. However, the serum 25(OH)D level change was negligible in subjects who received only 400 IU daily (p=0.4). In regards to the measured CMD risk markers, there were no significant changes found in either treatment group (p>0.05 for all).

The authors concluded that the lack of response in the CMD risk markers could indicate a need for a higher vitamin D3 supplementation dose for obese adolescents or longer duration of supplementation. They also propose that because there was only a modest increase in serum 25(OH)D, the effect on CMD risk markers was insufficient at this dose. Alternatively, vitamin D status may not be the only influence on obesity-related risk factors in this population. Further research is warranted.