Conjugated linoleic acid induces lipid peroxidation in humans

Abstract
Conjugated linoleic acid (CLA) is shown to have chemoprotective properties in various experimental cancer models. CLA is easily oxidised and it has been suggested that an increased lipid oxidation may contribute to the antitumorigenic effects. This report investigates the urinary levels of 8‐iso‐PGF, a major isoprostane and 15‐keto‐dihydro‐PGF, a major metabolite of PGF, as indicators of non‐enzymatic and enzymatic lipid peroxidation after dietary supplementation of CLA in healthy human subjects for 3 months. A significant increase of both 8‐iso‐PGF and 15‐keto‐dihydro‐PGF in urine was observed after 3 months of daily CLA intake (4.2 g/day) as compared to the control group (PP=0.015) in the CLA‐treated group. Thus, CLA may induce both non‐enzymatic and enzymatic lipid peroxidation in vivo. Further studies of the mechanism behind, and the possible consequences of, the increased lipid peroxidation after CLA supplementation are urgently needed.