A preliminary study on platelet aggregation in postmenopausal women consuming extra-virgin olive oil and high-oleic acid sunflower oil

The purpose of the present study was to examine the effects of two monounsaturated fatty acid-rich oils, extra-virgin olive oil (EVOO) and high-oleic sunflower oil (HOSO), on platelet aggregation in 74 postmenopausal women (aged 62.9 +/- 1.8 yr) with high-fat dietary habits. Both oils contained oleic acid as the major compound (approximate to 76% of total fatty acids), but the content of palmitic and linoleic acids and many minor compounds was significantly different. These oils were used as the only culinary fats during two 28-d periods, and represented approximate to 62% of the total lipid intake (approximate to 46% of total energy consumption). Other dietary components were matched. The daily energy contribution of saturated, monounsaturated, and polyunsaturated fatty acids to the total energy consumption was 11.8, 28.5, and 2.8%, respectively, during the EVOO dietary period and 10.3, 27.8, and 4.6%, respectively, with HOSO. Aggregation in platelet-rich plasma was measured after addition of ADP. Platelet aggregation (expressed as cm/5 min) was significantly lower after the EVOO diet than after HOSO (2.1 +/- 1.1 and 3.0 +/- 1.4, respectively; P < 0.05). Although maximal aggregation time was 40.2% higher in HOSO than in EVOO, the difference was not significant. Independent of serum cholesterol level, platelet aggregation tended to be different on the EVOO diet when women were classified according to cholesterol levels: <220 mg/dL or greater than or equal to 220 mg/dL. Results suggest that other compounds present in the oils aside from the fatty acids may play an important role in modulating platelet aggregation in these postmenopausal women.