Effect of meals rich in heated olive and safflower oils on oxidation of postprandial serum in healthy men

Abstract

The present randomised, crossover study sought to determine the effect of meals rich in safflower oil and olive oil (60 g) which had been heated for 8 h at 210 °C and the corresponding unheated oils on copper ion oxidation of dilute serum from 16 healthy men. Four hours after the meals rich in the heated oils, there were significant decreases of similar magnitude (−12%) in the lag time in conjugated diene formation during diluted serum oxidation. In the 12 subjects who consumed meals containing unheated oils, the lag time also decreased (−11%) significantly after the meal rich in unheated safflower oil (US) and did not change significantly after the unheated olive oil (UO) meal and these changes were different between the meals at a marginal level of significance ( P=0.05). Our data suggest that susceptibility to oxidation of lipoproteins in low antioxidant environments similar to dilute serum may be increased in the postprandial period following meals rich in heat-modified vegetable oils and unheated oils rich in polyunsaturated fatty acids but not following meals rich in native olive oil. These findings may be relevant to the choice of fat to replace saturated fats in lipid-lowering diets and to low risk of coronary heart disease in communities which have a high consumption of olive oil.