A comparison of the effects of dietary short and long chain saturated fatty acids on platelet functions, platelet phospholipids, and blood coagulation in rats.

Rats were fed for 20 weeks balanced purified diets solely enriched in fat, to determine whether, as in diets containing cholesterol and cholic acid, it was mostly the common dietary long chain saturated fatty acids (16:0 and 18:0) which could induce platelet function abnormalities. The dietary fats rich in 16:0 and 18:0 induced increased thrombin and adenosine diphosphate (ADP) platelet aggregation and an acceleration of the platelet-rich plasma clotting time. These effects on platelet functions were coupled with increased levels of 20:3 omega 6 and 20:3 omega 9 in total platelet phospholipids and a decrease of 22:4 and 24:4 omega 6 in the platelet phosphatidyl ethanolamine. Fatty acids that most closely correlated with thrombin aggregation and plasma clotting time (r = 0.99) were 20:3 omega 9 and 22:4 omega 6. There was no relationship between the effects of dietary fats on blood lipids and on blood platelets. Consequently, in different experimental models in rats, the dietary long chain saturated fatty acids appear to be responsible for certain platelet function abnormalities (clotting activity, response to thrombin aggregation). These platelet abnormalities might be due to changes in the platelet phospholipid fatty acid composition.