CLA: A Good Trans Fatty Acid?

Unlike most of the trans fatty acids produced by the industrial hydrogenation of refined oils, conjugated linoleic acid (CLA) has been a small part of the human diet for thousands of years. This is because it is found naturally in the meat and milk of ruminant animals (e.g. cattle, goats, elephants, antelope, deer, sheep, etc.). CLA has been shown to favorably affect body composition of animals (more lean and less fat) and also appears to provide some protection against atherosclerosis and cancer.

However, the amount of CLA available from food is much less than used in animal studies that have shown health benefits. In addition, the human body can convert other naturally occuring trans fatty acids into CLA.1The amount of CLA directly and indirectly obtained from natural sources would still result in considerably less CLA than has been shown to have beneficial effects in animal studies. A recent study in humans used at least three or four times more CLA than Americans are consuming for 13 weeks in subjects who had lost weight on a very low calorie diet. This study did find a modest increase in lean body mass in those receiving the CLA supplement compared to those receiving the placebo. However, overall body weight was not affected so the authors concluded that CLA ?did not result in improved body weight maintenance after weight loss.?2Bottom Line: There is some encouraging but preliminary research on possible health benefits from CLA but the amount found naturally in food is probably too small to have much benefit. Eating more CLA from red meat and dairy products would certainly promote heart disease, obesity and diabetes despite the small amount of potentially beneficial CLA in these foods. CLA is sold as ?Clarinol?. While the research on CLA supplements is somewhat encouraging so far there is insufficient data regarding the long term benefits and potential risks to recommend CLA supplements today.By James J. Kenney, PhD, RD, LD, FACN.1. Am J Clin Nutr 2002;76:504-102. Int J Obes 2003;27:840-7