The effectiveness of conjugated linoleic acid (CLA) as a weight-loss nutraceutical continues to be debatable, suggesting that there may be value in exploring the physiological effects of the lesser-known isomers. The effects of the minor isomer, trans-8, cis-10 (t8,c10)-CLA, in the form of an equimolar mixture with the cis-9, trans-11 (c9,t11) isomer, on body weight and body composition, circulating glucose and lipid concentrations, and liver weights were studied in sixty male Syrian golden hamsters," scientists writing in theBritish Journal of Nutritionreport.

"Animals were randomized to receive for 28 days a semi-purified, hypercholesterolaemic diet (5% dietary fat and 0.25% cholesterol) supplemented at the 2% level with either the t8, c10 + c9,t11-CLA mixture, c9,t11-CLA or trans-10, cis-12 (t10,c12)-CLA replacing lard and safflower-seed oil (control). compared with control, the t8, c10 + c9,t11-CLA mixture and t10,c12-CLA-fed animals had lower (P < 0.0001) fat mass following supplementation. Animals consuming t10,c12-CLA also possessed higher lean mass compared with control and c9,t11-CLA groups (P < 0.001). However, the livers of these animals were larger (P < 0.0001) compared with those in the control and other CLA groups. Body weights of the hamsters did not differ across the experimental groups. CLA treatments had no effect on serum glucose or lipid profile, except for inducing higher (P < 0.05) non-HDL-cholesterol concentration with t10,c12-CLA compared with the c9,t11 isomer," wrote S.V. Joseph and colleagues, Laval University.

The researchers concluded, "Overall, these results indicate that in male hamsters fed a hypercholesterolaemic diet, the t8,c10 + c9,t11-CLA mixture does not have an impact on blood lipid profile, but is able to effectively reduce fat mass, without incurring an accompanying liver enlargement."

Joseph and colleagues published their study in the British Journal of Nutrition ("Trans-8, Cis-10+cis-9, trans-11-conjugated Linoleic Acid Mixture Alters Body Composition in Syrian Golden Hamsters Fed a Hypercholesterolaemic Diet." British Journal of Nutrition, 2010;104(10):1443-1449).

Additional information can be obtained by contacting H. Jacques, Laval University, Dept. of Food Science & Nutrition, Quebec City, PQ G1V 0A6, Canada.<

From the December 20, 2010, Prepared Foods E-dition