Effect of oral administration of highly purified eicosapentaenoic acid on platelet function, blood viscosity and red cell deformability in healthy human subjects.

Eicosapentaenoic acid (EPA), which is abundant in seafood, has been reported to be a potent antagonist of platelet aggregation and also to reduce the incidene of cardiovascular disorders. We recently reported that EPA also reduces whole blood viscosity. A highly purified EPA, in a soft capsule (75% ethylester form of EPA; EPA-E), manufactured from sardine oil was administered to 8 healthy male subjects for 4 weeks. No side effects were observed. Platelet aggregation and platelet retention significantly decreased. The EPA content in platelet phospholipids markedly increased but docosahexaenoic acid (DHA) and arachidonic acid (AA) contents did not change. A reduction in whole blood viscosity and an increase in erythrocyte deformability were also observed after 4 week's ingestion of EPA-E. The EPA content in erythrocyte membrane phospholipids markedly increased after 4 weeks, and was positively correlated with erythrocyte deformability. Reduction of platelet aggregation and improvement of the rheological properties of the erythrocyte might be explained by an increase in the EPA content in platelet and erythrocyte phospholipids.