Does CLA Aid Weight Control?

Conjugated linoleic acid or CLA is formed by bacteria in the guts of ruminant animals such as cattle, sheep, and goats. The fat of these animals, including the fat in their milk, contains modest amounts of these naturally occurring trans fatty acids. The dairy and meat industries and the food supplement industries have suggested that CLA may have beneficial health effects. The health claim that has the most scientific support is that CLA may somehow aid weight control. Certainly with about two out of every three American adults and a growing number of kids overweight or obese, Americans need all the help they can get in losing weight and particularly in preventing weight regain after weight loss.

Two studies of human subjects that lasted just a few months found CLA supplements did not help people keep off weight they?d previously lost on a calorie restricted diet although one of these studies did suggests that those taking CLA increased their lean body mass compared to those taking a placebo. Based on this scant evidence CLA supplements have become popular in body builders and are also taken by quite a few people hoping they will help control their weight.A new study examined the impact of 3.4g of CLA or a placebo on body weight and composition in 101 obese subjects who had just lost 8% or more of their initial body weight on a calorie restricted diet. Fifty one took the CLA supplement and the remaining fifty subjects took a look-a-like placebo. The results of this study found CLA supplementation had no beneficial effects on either body composition or body weight after one year.1 CLA supplements do not help prevent people who have lost body fat from regaining that weight. The researchers did note a significant increase in the white blood cell count of those taking the CLA compared to those taking the placebo. Given that higher white blood cell counts have been associated with inflammation and a greater risk of coronary heart disease there is some reason to be concerned about the long-term safety of CLA in humans.By James J. Kenney, PhD, RD/LN, FACN1. Am J Clin Nutr 2006;83:606-12