Conjugated linoleic acid: a review.

Conjugated linoleic acid (CLA) refers to a group of positional and geometric isomers of the omega-6 essential fatty acid linoleic acid (cis-9, cis-12, octadecadienoic acid). In humans evidence is currently ambiguous as to whether CLA supplementation has a significant effect on body composition. Despite favorable changes in lipid levels in animal models, a beneficial effect in humans has not yet been established. While some of the changes reported are consistent with an improved lipid profile, declines in HDL and increases in lipoprotein (a) have also been observed in some subjects. Available evidence suggests CLA supplementation has no impact on immune system performance in healthy subjects.