Effect of Vanadium on Insulin Sensitivity in Patients with Impaired Glucose Tolerance

Background/Aim: Impaired glucose tolerance (IGT) is considered a risk factor for developing type 2 diabetes mellitus (T2DM) and is associated with insulin resistance. Vanadium seems to block protein tyrosine phosphatase with the consequent increment in insulin sensitivity ( INS) in T2DM patients, but this effect has not been studied in IGT patients. The aim of this study was to evaluate the effect of vanadium on INS in IGT patients. Methods: A randomized, double-blind, placebo-controlled clinical trial was carried out in 14 overweight/ obese patients with IGT. Intervention consisted of vanadyl sulfate ( VS, 50 mg p.o. twice daily) or placebo for 4 weeks. Before and after the intervention, a metabolic profile was performed and INS was assessed using the euglycemic-hyperinsulinemic clamp technique. Mann-Whitney U and Wilcoxon rank tests were used for statistical analyses. Results: There were no significant differences in basal characteristics between groups. VS did not affect INS [2.7 +/- 0.8 vs. 2.9 +/- 0.9 mg/(kg/min), p = 0.735] but increased triglyceride levels (1.35 +/- 0.61 vs. 1.70 +/- 0.46 mmol/l, p = 0.018). Conclusions: VS administration in IGT patients increased triglyceride concentrations without changes in INS. Copyright (C) 2008 S. Karger AG, Basel