The metabolic syndrome (MetSyn) is a cluster of metabolic abnormalities which is characterized by abdominal obesity, impaired fasting glucose (IFG), dyslipidemia and raised blood pressure. The MetSyn has been linked to an increased risk of developing both type 2 diabetes mellitus (T2DM) and atherosclerotic cardiovascular disease (ASCVD). The most recent guidelines from the National Cholesterol Education Program (NCEP) include a new definition for MetSyn, and have identified it as an important target of therapy. Using this new definition, it is estimated that 22% of Americans have the MetSyn in some form. Thus, the implication is that therapies aimed specifically at the MetSyn will be very important in reducing the incidence of T2DM and ASCVD. Supplemental trivalent chromium (Cr+3) has been shown to improve insulin sensitivity in some patients with T2DM, but its effect in patients at high risk of developing T2DM is unknown. There is also intriguing literature to suggest that supplemental Cr+3 may reduce weight and improve serum lipids, all of which are important components of the MetSyn. Additionally, recent in vitro data suggests that Cr+3 may also possess antioxidant and anti-inflammatory properties, further suggesting that supplemental Cr+3 might be useful in preventing T2DM and its complications. Thus, we propose to systematically evaluate the safety and efficacy of supra-physiologic doses of Cr+3 in obese adults with NCEP-defined MetSyn and IFG in a four-month, double-blind, randomized, placebo-controlled trial. Primarily, this trial will answer whether 1000 mcg of oral chromium picolinate (CrPic) taken daily can safely improve insulin sensitivity in this high risk population as measured by several indices obtained from an intravenous frequently sampled glucose tolerance test. This study will also quantify the effects of CrPic supplementation on other important clinical features seen in MetSyn including: serum high density lipoprotein cholesterol (HDL-C) and fasting triglycerides (TG); weight/body composition; and blood pressure. Additionally, this study will provide the first human data on the effects of CrPic supplementation on state-of-the art readouts of oxidant stress and inflammation, which are important intermediates in the development of both T2DM and ASCVD. Finally, the study will provide evidence of the relationship between chromium status and effects on insulin sensitivity as well as information on the prevalence of chromium deficiency in the MetSyn population. The results from this clinical trial will provide ample preliminary data for future R01 grant submissions further investigating the effects of CrPic supplementation in diabetes and coronary heart disease prevention.
| Iqbal, Nayyar; Cardillo, Serena; Volger, Sheri et al. (2009) Chromium picolinate does not improve key features of metabolic syndrome in obese nondiabetic adults. Metab Syndr Relat Disord 7:143-50 |
