The evaluation of the effect of vitamin D on insulin resistance in type II diabetic patients

Different studies have shown that vitamin D may play a functional role in insulin secretion and sensitivity. This study evaluates the effect of vitamin D on insulin resistance. This clinical trial was done on 100 patients with type II diabetes mellitus that aged 30-70 years. The patients were randomly selected and different examinations were done on them. They received 50000 units of oral vitamin D daily for four weeks. Insulin resistance was measured before and after the intervention. Data analysis was done by paired t-test and Wilcoxon test using SPSS software version 17. The participants consisted of 70 women and 30 men. Mean vitamin D was 43.03±19.28 ng/ml and 24% of the participants were vitamin D deficient based on the cut-off 25(OH) D <20 ng/ml. At the beginning and the end of the study, the mean levels for FPG, insulin, HOMA-IR were 138.48±36.74 and 131.02±39 mg/dl (P=0.05), 10.76±9.46 and 8.6±8.25 µIu/ml (P= 0.02), and 3.57±3.18 and 2.89±3.28 (P= 0.008), respectively. The findings of this study showed that vitamin D causes significant improvements in FPG, insulin, and insulin resistance, that was evaluated by HOMA-IR. It was also indicated that adding vitamin D supplements can improve glucose control in type II diabetes mellitus.