Effect of Vitamin D Supplementation on Obesity-Induced Insulin Resistance: A Double-Blind, Randomized, Placebo-Controlled Trial.

Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Internal Medicine and Transplant Unit, San Raffaele Hospital, Milan, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Center for Diabetes and Metabolic Diseases, Association of Italian Knights of the Sovereign Military Order of Malta, Rome, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Division of Endocrinology, Department of Clinical Medicine and Surgery, Federic II University, Naples, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.Center for Endocrine and Metabolic Diseases, Gemelli University Polyclinic Foundation, Catholic University of the Sacred Heart, Rome, Italy.

Obesity (Silver Spring, Md.). 2018;(4):651-657
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Abstract

OBJECTIVE The aim was to investigate whether vitamin D supplementation, combined with a hypocaloric diet, could have an independent effect on insulin sensitivity in subjects with both overweight and hypovitaminosis D. Changes from baseline in anthropometric parameters, body composition, glucose tolerance, and insulin secretion were considered as secondary outcomes. METHODS Eighteen volunteers who were nondiabetic and vitamin D deficient and had BMI > 25 kg/m2 were randomized (1:1) in a double-blind manner to a hypocaloric diet + either oral cholecalciferol at 25,000 IU/wk or placebo for 3 months. Hyperinsulinemic-euglycemic clamp to measure insulin sensitivity was performed at baseline and after intervention. RESULTS Body weight in both groups decreased significantly (-7.5% in the vitamin D group and -10% in the placebo group; P < 0.05 for both), with no between-group differences. Serum 25-hydroxyvitamin D levels in the vitamin D group increased considerably (from 36.7 ± 13.2 nmol/L to 74.8 ± 18.7 nmol/L; P < 0.001). Insulin sensitivity in the vitamin D group improved (from 4.6 ± 2.0 to 6.9 ± 3.3 mg·kg-1 ·min-1 ; P < 0.001), whereas no changes were observed in the placebo group (from 4.9 ± 1.1 to 5.1 ± 0.3 mg·kg-1 ·min-1 ; P = 0.84). CONCLUSIONS Cholecalciferol supplementation, combined with a weight loss program, significantly improves insulin sensitivity in healthy subjects with obesity and might represent a personalized approach for insulin-resistant subjects with obesity.

Methodological quality

Publication Type : Randomized Controlled Trial

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