Conjugated linoleic acid and the control of cancer and obesity

The effects of conjugated linoleic acid (CLA) in animals are reviewed. In m ost of the CLA preparations that have been investigated to date for biologi cal activity, two CLA isomers are present in about equal concentrations: ci s-9,trans-11 CLA, and trans-10,cis-12 CLA. The occurrence of these isomers in foods and their production by rumen microorganisms are discussed. Potent ial mechanisms of action as regards the effects of CLA on cancer and body c omposition are reviewed, including recent evidence that body composition ch anges are produced by the trans-10,cis-12 CLA isomer. Evidence is presented indicating that CLA may modulate cellular response to tumor necrosis facto r-alpha (TNF-alpha). The mechanistic implications of this finding are consi dered.