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 mon ounsaturated fatty acid-rich oils, extra-virgin olive oil (EVOO) and h igh-oleic sunflower oil (HOSO), on platelet aggregation in 74 postmeno pausal women (aged 62.9 +/- 1.8 yr) with high-fat dietary habits. Both oils contained oleic acid as the major compound (approximate to 76% o f total fatty acids), but the content of palmitic and linoleic acids a nd many minor compounds was significantly different. These oils were u sed as the only culinary fats during two 28-d periods, and represented approximate to 62% of the total lipid intake (approximate to 46% of t otal energy consumption). Other dietary components were matched. The d aily energy contribution of saturated, monounsaturated, and polyunsatu rated 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 wa s measured after addition of ADP. Platelet aggregation (expressed as c m/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 differenc e was not significant. Independent of serum cholesterol level, platele t 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 i n the oils aside from the fatty acids may play an important role in mo dulating platelet aggregation in these postmenopausal women.