Effects of diets high in saturated fatty acids, canola oil, or safflower oil on platelet function, thromboxane B₂ formation, and fatty acid composition of platelet phospholipids

Platelet function and fatty acid composition were investigated in 30 healthy male subjects who ate a controlled-saturated-fatty-acid (baseline) diet for 3 wk and then consumed either safflower oil or canola oil as a major fat source for 8 wk. Fatty acid composition of platelet phospholipids reflected changes in dietary fatty acid composition. Compared with baseline a 35% decrease (P < 0.05) in arachidonic acid was observed in platelet phospholipids of the canola-oil diet group while long chain n-3 fatty acids rose 7-26% (P > 0.05). Compared with baseline both unsaturated-fatty-acid diets reduced platelet aggregation at 3 wk of oil-based diet feeding (P < 0.01) whereas only canola oil influenced platelet function (lowered ATP secretion) at 8 wk (P < 0.01). No significant difference was observed in thromboxane B₂ concentrations between oil-treatment groups at 8 wk. Both oil-based diets had short-term beneficial effects on platelet function but the effect of canola oil persisted longer.