CLA, Arginine May Increase Lean Body Mass

Conjugated Linoleic Acid (CLA) and arginine modulated adipose tissue metabolism by separate, but not additive,effects; and CLA and arginine may have depressed muscle protein turnover (J Nutr. 2009;139(7):1279-85). Sprague Dawley rats were assigned to the following dietary groups (n= 6/group; 5 week total): Group 1: Control (2.55 percent L-alanine plus 1.5 percent canola oil); Group 2: Arginine (1.25 percent L-arginine plus 1.5 percent canola oil); Group 2: CLA (2.55 percent L-alanine plus 1.5 percent CLA); and Group 4: Arginine plus CLA (1.25 percent L-arginine plus 1.5 percent CLA). Supplemental amino acids were provided in drinking water and CLA was incorporated into the food pellets. Daily weight gain, food intake, arginine intake and final body and eviscerated body weights were greater in rats fed supplemental CLA then in rats fed canola oil. The retroperitoneal adipose tissue: body weight ratio was less in rats fed supplemental CLA than in rats fed canola oil, but epididymal adipose tissue, liver and soleus and extensor digitorum longus muscle weights were unaffected by arginine or CLA. CLA decreased epididymal adipose tissue concentrations of palmitoleic, oleic and cis-vaccenic acid. CLA and arginine increased palmitate oxidation to CO2 in epididymal adipose tissue in vitro relative to control rats. Glucose and palmitate incorporation into total lipids in epididymal adipose tissue was lower in rats fed supplemental arginine than in alanine-fed rats. Arginine increased plasma glycerol relative to alanine-fed rats and CLA and arginine independently decreased most serum essential amino acids and alanine, glutamate, glutamine and ornithine.