Biological effects of conjugated linoleic acid on obesity-related cancers

Considerable evidence suggests that obesity and overweight play an important role in cancers i.e., breast, colon, endometrial, kidney, pancreatic, and liver. In fact, overweight and obesity are now established risk factors for cancer and cancer-related mortality. Conjugated linoleic acid (CLA) consists of a group of positional and geometric fatty acid (FA) isomers that are derived from linoleic acid (LA) [18:2(n-6)], which occurs naturally in food with a high concentration in products from ruminant animals. Studies in both in vitro cell and in vivo animal models have shown that CLA, specifically cis 9-trans 11 and trans 10-cis 12 CLA isomer, inhibits the initiation and promotion stages of carcinogenesis, suggesting that CLA has received considerable attention as a chemopreventive agent. In this review, the biological activities and multiple mechanisms of CLA in obesity-related cancers including cell lines, animal models and clinical observations are explained.