Lowery, L. M.; Appicelli, P. A.; Lemon, P. W.R. FACSM

CONJUGATED LINOLEIC ACID ENHANCES MUSCLE SIZE AND STRENGTH GAINS IN NOVICE BODYBUILDERS

Abstract

Conjugated linoleic acid (CLA), an uncommon dietary lipid, is both anabolic and lipolytic in animals (Chin et al., J. Nutr. 124: 2344-2349, 1994; West et al., FASEB J. 11(3): A599, 1997). To investigate whether CLA enhances muscle development in novice bodybuilders, 24 men(19-28y) ingested 7.2 g•d-1 CLA or placebo (vegetable oil) while completing 6 wk of bodybuilding exercise. Gains in CLA subjects were greater than placebo for skinfold-corrected arm girth: before CLA (CLA-b) = 7175±978 and after (CLA-a) = 7562±1000 mm2 vs placebo before (PB-b) = 7777±1532 and after (PB-a) = 7819±1516 mm2; p=0.02), body mass: CLA-b = 77.6±11.8 and CLA-a = 79.0±12.0 kg vs PB-b = 77.8±11.9 and PB-a = 77.8±12.2 kg; p=0.01), and leg press 1RM: CLA-b = 263.6±63.0 and CLA-a = 335.0±75.1 kg vs PB-b = 271.5±62.9 and PB-a = 306.8±70.2 kg; p=0.04). Subcutaneous fat (skinfolds), total body fat (bioelectrical impedance analysis [BIA]), and body water distribution (ICF vs ECF; multifrequency BIA) of both whole body and upper limb were similar in both groups (p>0.20). A subset of subjects revealed NS differences in tympanic temperature, or in serum glucose, lipids, BUN:creatinine ratio, LDH, SGOT and SGPT enzymes. Apparently CLA acts as a mild anabolic agent in novice male bodybuilders without causing significant water or adipose gain.