Saturday, August 7, 2010

CLA: Good For Fat-Loss, Bad for Your Liver

Molecular structure of conjugated linoleic acid
(CLA, HMDB v2.5)
After being hyped as the next big thing in the weight-loss business, interest in the anti-lipidemic effects of CLA has certainly diminished over the past months. A recent investigation by Joseph (Joseph. 2010) may well restore scientific interest in its metabolic effects.

The scientists found a significant increase in lean-body mass that was accompanied by a decrease in fat mass in hamsters fed with a diet supplemented with a CLA-mixture containing the isomeres t8, c10+c9, t11-CLA and another mixture of t10, c12-CLA. The third mixture, i.e. c9, t11-CLA, on the other hand, did not exhibit similar positive effects on body composition. It did however have the same negative effects on liver size as the other CLA-mixture.

While it certainly is questionable if and in how far the results are transferable to a human context the increase in liver weight is another negative side effect which adds to the disappointing and conflicting results of previous studies (cf. review by Plourde. 2008) on the weight loss effects of CLA in humans vs. animals. It does however stand out of question that the metabolic effects of different CLA-isomeres are very distinct from another and costumers should watch out for products containing either t8,c10+c9, t11 or t10,c12-CLA. If the exact isomers are not given, choose another product.