The effect of zinc supplemention on glycosylated hemoglobin in type II diabetic patients

Diabetes mellitus is one of the most common metabolic disorders due to partial or complete deficiency of insulin or insulin resistance. The most common problems in uncontrolled diabetes are chronic complication including renal and cardiovascular failure. Zinc as an essential trace element, can affect some aspects of insulin synthesis, secretion and function. The aim of this study was to evaluate the effect of zinc supplementation in diabetes control status in a group of type-II diabetic patients. In this clinical trial, 60 diabetic patients (type-II) were divided in 2 groups, randomly. One of them consumed 25 mg/day zinc and the other had 50 mg daily for 2 months. Fasting blood glucose (FBS), 2 hour post prandial blood glucose (2hpp), glycosylated hemoglobin (HbA1c), and serum levels of zinc were evaluated in patients before and after zinc supplementation. Wilcoxon and Mann-Whitney tests were used for statistical analysis. 22 patients in each group with the mean age of 48 years completed the study. Serum levels of zinc in the group with 25 mg/day supplementation didn’t show significant change, but in the second group increased significantly after supplementation (160±30 μg/dl vs 140±30, p=0.002). HbA1c significantly reduced after supplementation (9.7±1.86 vs 8.9±1.5, p=0.02). There were not significant changes in FBS and 2hpp before and after zinc supplementation. Our results indicate that elevation of zinc level in diabetic patients has favorable effect on HbA1c and diabetes control status. It is assumed that some of the diabetic patients suffer from a latent zinc deficiency and this may be unfavorably affect diabetes control status.