Platelet aggregation, thromboxane production and thrombogenic ratio in postmenopausal women consuming high oleic acid-sunflower oil or palmolein.

BACKGROUND

Saturated fatty acids exert controversial effects on platelet aggregation and eicosanoid production.

AIM

To investigate the effect of a dietary exchange between palmitic acid and oleic acid on both platelet aggregation and thromboxane B2 (TXB(2)) production, and on urine TXB(2), prostacyclin I2 (PGI(2) as 6-keto-protaglandin F(1)alpha), and the thrombogenic ratio (TXB(2)/6-keto-protaglandin F(1)alpha) in fourteen postmenopausal women.

EXPERIMENTAL DESIGN

Women were assigned to two consecutive 28-d dietary periods that were high in cholesterol (400 mg/d) and fat (46%en). In the first period all subjects followed an oleic acid-rich diet prepared with high oleic acidsunflower oil. This was followed by a second period rich in palmitic acid in the form of palmolein. DETERMINATIONS: Nutrient intakes, ADP-platelet aggregation, platelet TXB(2) production, urine TXB(2) and 6-keto-protaglandin F(1)alpha were measured during two dietary periods and the results obtained correlated to serum cholesterol, lipoproteincholesterol and peroxides, apolipoproteins and plasma tocopherol.

RESULTS

The palmolein diet led to an increase in the platelet aggregation rate (p < 0.05) and in the time for the maximal aggregation rate (p < 0.02). No significant differences were observed in platelet TXB(2) production. Palmolein increased urine TXB(2) in pg/mL (p < 0.05) and pg/min (p < 0.01), whereas the thrombogenic ratio (TXB(2)/6-keto-protaglandin F(1)alpha) did not change. Most changes were related to oil change, few to serum cholesterol level (< or > or = 6.2 mmol/L) or age (< or > or = 65 yr).

CONCLUSIONS

Palmolein diet activates platelet aggregation more in normocholesterolemics. Though palmolein increased thromboxane and tended to increase prostacyclin in urine in normo- and hypercholesterolemic women, the thrombogenic ratio did not change. These effects were related to the LDL and HDL concentration increases and to the absence of change in the total cholesterol/HDL-cholesterol ratio found following the dietary intervention.