Effects of conjugated linoleic acid supplementation on blood lipids and adiposity of rats fed diets rich in saturated versus unsaturated fat

Conjugated linoleic acid (CLA) may decrease adiposity and improve blood lipid profiles under some conditions. The goal of this study was to determine the effects of CLA supplementation on blood lipid profiles and adiposity of rats fed a diet containing a primarily saturated fat versus a diet containing a primarily unsaturated fat. Twenty-eight male Sprague-Dawley rats were randomly assigned to one of four diets containing coconut oil, coconut oil with CLA, corn oil or corn oil with CLA. After 28 days, blood was collected and serum concentrations of total cholesterol (TC), HDL-cholesterol (HDL-C), and triacylglycerols (TG) were assessed. Food intake, body weights, and epididymal fat pads were measured. No significant differences (p > 0.05) were noted among groups for amount of food consumed, weight gained, food efficiency ratio or serum TG concentrations. TC concentrations were lower (p < 0.05) in the CLA-supplemented rats that were fed coconut oil but not those consuming corn oil. Serum HDL-C was lower (p < 0.05) in rats consuming corn oil but was not significantly different (P > 0.05) for CLA supplemented groups. Epididymal fat pads weighed significantly more (p < 0.05) in the coconut oil fed group compared to the corn oil fed group, but there was no significant difference (p > 0.05) between the corn oil and coconut oil + CLA group. Overall, this study suggests that CLA is more beneficial for control of blood lipids and adiposity when supplemented to a diet rich in saturated versus unsaturated fat. (c) 2005 Elsevier Ltd. All rights reserved.