The risk of chromium picolinate supplementation in normolipidemic rats fed regular or high fat diet. (c2005)

Abstract

Chromium, an essential nutrient involved in carbohydrates and lipid metabolism, has been marketed as a dietary nutritional supplement in the form of chromium picolinate (Crp). The objective of this study is to investigate the effect of Crp supplementation on blood lipid profile in addition to other parameters in normolipidemic rats fed with either a regular or a high fat diet. Crp was administered to rats in drinking water as a low (0.286~g/1 OOg body weight/day), in equivalence to 200~g/70kg in human, or high dose (1.43~gll1 OOg body weight/day), in equivalence to 1 000~g/70kg in human, for a period of 2 months. Control groups, however, received similar diets but with plain water. Assessment of liver enzyme activities revealed that, with respect to the control group, Crp supplementation increased SGOT activity in rats fed with either diet. It also increased ALP and LDH activities in the high fat diet group. SGPT, however, exhibited a significant decrease only with the regular fat diet. Serum insulin concentrations were not affected by Crp supplementation in all groups fed the regular fat diet. However it increased in a dose dependent manner in rats fed the high fat diet with significance reached with the high dose of Crp. Serum glucose concentrations and glucose tolerance tests were not affected by both Crp doses used regardless of the fat content in the diet. In the presence of a regular fat diet, Crp supplementation did not affect serum concentrations of total cholesterol, high density lipoprotein (HDL) cholesterol, Triacylglycerol (TAG), very low density lipoproteins (VLDL) TAG, VLDL cholesterol, VLDL phospholipid, and VLDL apolipoprotein B (apo B). However, it increased significantly low density lipoprotein (LDL) cholesterol, LDL TAG, LDL apo B and serum total apo B with the high dose of Crp. In the presence of a high fat diet, both Crp supplementation doses increased significantly serum concentrations of total apo B, total cholesterol and TAG, but not HDL-cholesterol. No Crp-induced changes were observed in serum iron concentration, liver fat content and stool concentrations of cholesterol and TAG in all groups regardless of the fat content in the diet. In conclusion, Crp supplementation of normolipidemic rats with the recommended dose in concomitance with a regu lar fat diet, may not be harmful but also not beneficial. However, high doses of Crp are not recommended because of delayed clearance and metabolism of lipoprotein particles. In the presence of a high fat diet, Crp supplementation appeared to have a negative impact on blood lipid profile, liver enzymes and hyperinsulinemia regardless of the Crp dose used. Further similar studies on human subjects may be necessary to confirm the observed effects on rats because of possible species differences.