Conjugated Linoleic Acid - History

History

In 1979, researchers from the University of Wisconsin applied a beef extract to mice skin. The mice were then exposed to a strong carcinogen. When the researchers counted the number of tumors developed by the mice 16 weeks later, they found, to their surprise, that the mice exposed to the beef extract had 20% fewer tumors. The identity of this anticarcinogen was not discovered until almost a decade later, in 1987. Michael Pariza, the scientist who discovered CLA, later remarked that "few anticarcinogens, and certainly no other known fatty acids, are as effective as CLA in inhibiting carcinogenesis in these models." Although CLA is best known for its anticancer properties, researchers have also found that the cis-9, trans-11 form of CLA can reduce the risk for cardiovascular disease and help fight inflammation.

The Nutritional Immunology and Molecular Medicine Laboratory demonstrated that oral CLA treatment prevents or ameliorates inflammatory bowel disease by activating the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR gamma). In 2012, NIMML conducted a human clinical trial administering 6 grams/day of a CLA supplement to Crohn's disease patients and reported a remarkable improvement in Crohn's disease activity index and quality of life measures. These clinical improvements paralleled modulation of T cell responses in blood subjects that received CLA supplement.

CLA is also known for its body weight management properties, which include reducing body fat and increasing lean muscle mass. Over 30 clinical studies have been published investigating the effect of CLA on weight management. The trials have quite variable designs, which leads to inconsistency. However a meta-analysis conducted in 2007 concluded CLA has a small impact on fat mass.

In July 2008, CLA received a no objection letter from the FDA on its Generally Recognized as Safe (GRAS) status for certain food categories, including fluid milk, yogurt, meal replacement shakes, nutritional bars, fruit juices and soy milk. With GRAS status, food companies are now able to add CLA to products in these food categories.