Ingestion of moderately thermally oxidized polyunsaturated fat decreases serum resistance to oxidation in men with coronary artery disease

We have examined the effects of ingesting moderately thermally oxidized and unheated polyunsaturated fatty acid (PUFA)–rich vegetable oils on postprandial oxidative stress, serum and lipoprotein oxidation, paraoxonase-1 activity, and circulating cell adhesion molecules in men with coronary artery disease (CAD) and in healthy controls. Twenty-four men with stable CAD and 20 healthy men were randomized to receive a meal rich in thermally oxidized (1 hour at 180°C) sunflower oil (TSO) or the corresponding unheated oil (USO) in a crossover trial with 1 week between meals. Blood was taken at baseline and 4 and 6 hours after the meals. In men with CAD, the lag time in dilute serum oxidation by copper ions decreased significantly (−16%, P < .01) during the TSO meal; and this change was significantly different (P < .05) compared with the USO meal. Plasma soluble vascular cell adhesion molecule–1 concentration, a marker of endothelial activation, increased (4%, P < .05) significantly during the TSO meal and decreased (−5%, P < .05) significantly at 4 hours after the USO meal; and these changes were significantly different (P = .02). In both groups of men, plasma peroxides (5%-11%) and vitamin E (6%-12%) increased significantly (P < .05) whereas serum paraoxonase-1 activity and oxidized low-density lipoprotein concentration did not change significantly during both meals. This study suggests that ingestion of a PUFA vegetable oil moderately oxidized in line with domestic cooking methods may enhance the postprandial environment for lipoprotein oxidation but not sufficiently to appreciably increase levels of oxidized low-density lipoprotein and endothelial activation in men with CAD. However, it may be prudent for men with CAD to avoid using PUFA-rich vegetable oils in cooking.