CLINICAL AND EXPERIMENTAL-STUDY ON THE LONG-TERM EFFECT OF DIETARY GAMMA-LINOLENIC ACID ON PLASMA-LIPIDS, PLATELET-AGGREGATION, THROMBOXANEFORMATION, AND PROSTACYCLIN PRODUCTION

Effects of a dietary intake of the polyunsaturated omega-6 essential f atty acids (EFAs) linoleic and gamma-linolenic acids (GLA) on blood li pids, platelet function, and vascular prostacyclin production were stu died in 12 hyperlipidemic patients (doses of 3 g/day) and 12 male Wist ar rats (doses of 3 mg/kg/day) for 4 months. In humans, GLA supplement ation decreased plasma triglyceride (TG) levels by 48% (p < 0.001) and increased HDL-cholesterol concentration by 22% (p < 0.01). Total chol esterol and LDL-cholesterol levels were significantly decreased by ome ga-6 EFAs. Platelet aggregation induced by low concentrations of adeno sine diphosphate (ADP) and epinephrine, and serum thromboxane B-2 decr eased by 45% both in humans and animals after GLA supplementation. Ble eding time increased 40% (p < 0.01). In rats, vascular prostacyclin pr oduction measured by radioimmunoassay of 6-keto-PGF(1 alpha) was enhan ced by GLA intake. These effects of omega-6 EFAs may contribute to car diovascular protection and prevention of the atherosclerotic disease.