Eicosanoid production, thrombogenic ratio, and serum and LDL peroxides in normo- and hypercholesterolaemic post-menopausal women consuming two oleic acid-rich diets with different content of minor components

The present paper compares the effects of two monounsaturated oils, extra v irgin olive oil (EVOO) and high-oleic acid sunflower oil (HOSO), on serum a nd LDL peroxides, eicosanoid production and the thrombogenic ratio (thrombo xane (TX) B-2:6-keto-prostaglandin F-1 alpha) in fourteen non-obese post-me nopausal women. The subjects, mean age 63 (SD 11) years, were assigned to t wo consecutive oleic acid-rich 28 d dietary periods. EVOO and HOSO represen ted 62 % of the total lipid intake and were used as the only culinary fat d uring the first and second dietary periods respectively. Serum peroxides, p lasma alpha -tocopherol and TXB2 levels in stimulated platelet-rich plasma (PRP-TXB2) were significantly higher (P < 0.01, P < 0.001, and P < 0.05 res pectively) after the HOSO diet than after the EVOO diet. The relationship b etween the serum cholesterol level (< 6.21 mmol/l or greater than or equal to6.21 mmol/l) and the type of dietary oil on eicosanoids, peroxides and al pha -tocopherol were evaluated by two-way ANOVA. Dietary oil significantly affected (P < 0.05) the PRP-TXB2 level, whereas serum and LDL peroxides wer e significantly affected (P < 0.001 and P < 0.01 respectively) by the serum cholesterol level. The plasma <alpha>-tocopherol level was significantly a ffected by the serum cholesterol level and the type of dietary oil (both P < 0.001). No significant relationships were found between serum cholesterol levels, serum peroxide or LDL peroxide levels, plasma <alpha>-tocopherol c oncentrations or alpha -tocopherol intakes with eicosanoid production or th e thrombogenic ratio due to dietary changes. However, in spite of their hig her alpha -tocopherol levels, hypercholesterolaemic subjects showed increas ed peroxidation in serum and LDL in comparison with normocholesterolaemic s ubjects on the HOSO diet in comparison with the EVOO diet. These findings s uggest that differences in the type of minor compounds, as well as in the c oncentration of linoleic acid, in both these monounsaturated oils may play an important role in modulating eicosanoid production and lipoprotein perox idation when they constitute a large proportion of the diet of post-menopau sal women.