Endocrine Abstracts

Introduction: The prevalence of vitamin D deficiency is higher in obese individuals but it is unclear whether vitamin D deficiency impacts body composition or if body composition impacts the vitamin D status. The research regarding vitamin D supplementation and weight loss in obese individuals is ambiguous. One hypothesis for the presumed fat reductive effect of vitamin D is that vitamin D inhibits adipocyte differentiation.

Aim: To investigate if treatment with vitamin D can reduce fat mass in obese men with vitamin D deficiency.

Methods: This study was designed as a randomized prospective, placebo controlled, double blind intervention. Thirty eight overweight men (BMI > 25 kg/m²) with vitamin D deficiency (25(OH)D < 55 nmol/l) were randomized to receive 2000 IU Cholecalciferol drops or the equivalent amount of placebo drops for 6 months. At baseline and after 6 months body composition and BMI was measured and blood samples were obtained; body composition was measured using bioelectrical impedance analysis (BIA).

Results: The mean change in body fat percentage for the vitamin D group and the placebo group was a 0.6%-units (baseline compared to follow up; P=0.222) and a 0.1%-units (P=0.857) increase, respectively. The mean change in BMI in the vitamin D group was a 0.2 kg/m² decrease (P=0.272) and for the placebo group a mean decrease in BMI of 0.5 kg/m² (P=0.049). There was no statistically significant difference between the placebo group and the intervention group regarding change in fat percentage or BMI (P=0.544, P=0.256, respectively). Moreover no statistically significant difference was observed between the groups regarding change in any of the metabolic laboratory values.

Conclusion: We conclude that treatment with 2000 IU vitamin D daily for 6 months does not impact BMI or fat percentage in overweight men with vitamin D deficiency.