Effects of zinc supplementation on serum leptin level and insulin sensitivity in obese people

Objectives: Obesity is a crucial risk factor for many disorders. The level of minerals such as zinc is low in serum, plasma or erythrocytes of obese patients. Zinc plays a role in fat metabolism, appetite control, insulin resistance, and obesity. On the other hand, hormones such as leptin have a key role in regulation of energy balance. The aim of this study was to assay effects of zinc supplementation on leptin level and insulin sensitivity in obese people. Method: This study was conducted on 60 eligible obese people (BMI > 30 kg/m(2)) randomly divided to intervention-control groups. Intervention group received a 30 mg/d zinc pill and placebo group received a 30 mg/d isomaltose pill for a period of 4 weeks. Serum leptin and zinc level were measured by enzyme-linked immunosorbent assay and atomic absorption spectrophotometer, respectively. In. addition, Insulin level and Insulin resistance (IR) were determined by immunoenzymometric assay and (HOMA-IR) model. Results: A significant increase in serum leptin level was observed in zinc group (< 0.05). There were no significant differences in post intervention serum leptin level between the two groups (p > 0.05). Serum zinc concentration increased in both groups, but it was only significant in the intervention group. Serum insulin level and HOMA-IR index decreased in both groups after 4 weeks. These reductions were significant in the zinc group compared to initial level (< 0.05). Conclusion: Zinc supplementation in obese people may be an effective approach in reducing insulin resistance complications and improving zinc deficiency. The future studies are recommended to assay other inflammatory biomarkers and with longer duration in obese population.