Short-term trials involving the dietary supplement conjugated linoleic acid (CLA) have suggested that it may reduce body fat mass (BFM) and increase lean body mass. However, until recently, little was known about the long-term effects of CLA. That led a team of scientists from Norway to observe how CLA affected body composition and safety variables in healthy men and women with a body mass index between 25 and 30.
As reported in The American Journal of Clinical Nutrition (2004; 79 , 1118–25), study participants were randomly given either a type of CLA or a placebo. After 1 year of supplementation, those who received the CLA had a significantly lower BFM than those in the control group; these changes were not associated with diet or exercise, and adverse events did not differ between the groups. This led the researchers to conclude that long-term CLA supplementation “reduces BFM in healthy overweight adults.”