Effects of Different Forms of Chromium Supplements on Serum Glucose, Insulin and Lipids in Rats

This study evaluated the effects of different forms of chromium supplements on serum glucose, insulin and lipid concentrations in rats. Sprague-Dawley male rats were randomly assigned to one of three dietary groups and fed AIN-76 semi-purified basal diets supplemented with 300 ppb Cr from Cr methionine (CrMet) and Cr chloride $(CrCI_3)$ or without Cr (control). By the end of the $4^{th}$ week, all rats were decapitated, blood collected, and serum glucose, insulin and lipid concentrations were determined. The CrMet and $CrCl_3$ supplementation did not affect weight gain and feed efficiency ratio. However, feed intake was significantly higher in CrMet groups than control (p < 0.05). CrMet-supplemented rats had markedly increased insulin levels (p < 0.05) compared with controls. Serum lipids were not significantly different between the control and the CrMet groups. $CrCl_3$ supplementation decreased total cholesterol and triglyceride, but the decreases were only significant for the control group. $CrCl_3$ supplementation was associated with significant decreases in total cholesterol compared with CrMet supplementation. These results indicate that CrMet supplementation is effective for increasing serum insulin, and $CrCl_32$ may improve lipid concentrations, because we observed decreased serum total cholesterol and an improved total cholesterol/HDL-cholesterol ratio (THR).