Chromium and Insulin Resistance

Chromium is an essential nutrient for the maintenance of normal glucose tolerance and its deficiency causes insulin resistance. Chromium administration has also been shown in several studies to lower glucose and insulin levels in patients with type 2 diabetes. Moreover, studies in humans, animals and cell culture indicate that chromium enhances insulin signaling. While these studies suggest that chromium administration increases insulin sensitivity, it has not been directly demonstrated that chromium has an effect in well defined insulin resistant subjects independent of hyperglycemia. Accordingly, we propose to perform a placebo-controlled study of chromium picolinate administration in a cohort of non-obese, non-diabetic, insulin resistant subjects. The insulin sensitivity of 80 subjects will be measured by a euglycemic insulin clamp. Approximately 40 insulin resistant subjects will be randomized to 16 weeks of therapy with either 500 ug twice a day of chromium picolinate or placebo. To quantitate the chromium-induced improvements, euglycemic hyperinsulinemic clamps to evaluate insulin sensitivity, OGTT using deuterated glucose to evaluate glycolytic glucose disposal, and muscle biopsies to evaluate insulin signaling pathways, will be performed before and after treatment. We believe these studies will (1) confirm the beneficial effect of chromium on insulin sensitivity; (2) further our understanding of the molecular mechanisms of chromium action; and (3) because these insulin resistant subjects are at risk for the development of type 2 diabetes, the Metabolic Syndrome, and coronary artery disease (CAD), a demonstration of the beneficial effects of chromium on insulin action could ultimately have important public health consequences.