Zinc supplementation and the effects on metabolic status in gestational diabetes: A randomized, double-blind, placebo-controlled trial

ObjectiveTo the best of our knowledge, no reports are available indicating the effects of zinc supplementation on metabolic status in women with gestational diabetes (GDM). This study was designed to determine the effects of zinc supplementation on glucose homeostasis parameters and lipid concentrations in GDM women.MethodsThis randomized, double-blind, placebo-controlled trial was performed among 58 women diagnosed with GDM, primigravida and aged 18-40 years old. Patients were randomly divided into two groups to receive 233 mg zinc gluconate (containing 30 mg zinc) supplements (n = 29) or placebo (n = 29) per day for 6 weeks. Fasting blood samples were taken at the beginning and end of the trial to quantify glucose, insulin and lipid concentrations.ResultsPatients who received zinc supplements had significantly higher serum zinc concentrations (+ 6.9 ± 13.2 vs. − 1.5 ± 16.5 mg/dL, P = 0.03) than those received the placebo. In addition, zinc-supplemented patients had reduced fasting plasma glucose (FPG) (− 6.6 ± 11.2 vs. + 0.6 ± 6.7 mg/dL, P = 0.005), serum insulin levels (− 1.3 ± 6.6 vs. + 6.6 ± 12.2 μIU/mL, P = 0.003), homeostasis model of assessment-insulin resistance (HOMA-IR) (− 0.5 ± 1.6 vs. + 1.5 ± 2.7, P = 0.001), homeostatic model assessment-Beta cell function (HOMA-B) (− 0.7 ± 25.0 vs. + 26.5 ± 49.5, P = 0.01) and increased quantitative insulin sensitivity check index (QUICKI) (+ 0.01 ± 0.01 vs. − 0.01 ± 0.02, P = 0.004) compared with the placebo. Additionally, significant differences in serum triglycerides (+ 13.6 ± 61.4 vs. + 45.9 ± 36.5 mg/dL, P = 0.01) and VLDL-cholesterol concentrations (+ 2.7 ± 12.3 vs. + 9.2 ± 7.3 mg/dL, P = 0.01) were observed following the administration of zinc supplements compared with the placebo.We did not observe any significant effects of taking zinc supplements on other lipid profiles.ConclusionsTaken together, 30 mg zinc supplementation per day for 6 weeks among GDM women had beneficial effects on metabolic profiles.