[Essential fatty acids in cardiovascular physiopathology]

Numerous studies have shown that a limitation of dietary saturated fatty acids and cholesterol associated with an increase in linoleic acid consumption lowers high blood cholesterol level (a risk factor in the development of atherosclerosis). Besides the importance of dietary fatty acid composition in determining blood lipoprotein concentrations, it has been shown that increased intake of dietary linoleic acid influences arterial thrombosis tendency in rats and improves blood platelet function in man. Linoleic acid rich diets also loffer arterial blood pressure in salt loaded rats and in hypertensive men. Moreover, these diets improve heart function in rats as measured by coronary perfusion rate and ventricular work. These favourable effects of linoleic acid on various risk factors of cardiovascular diseases are observed at dietary levels which largely exceed the minimum amount required to prevent or cure the essential fatty acid deficiency syndrome. It is evident that the study of the physiological effects of linoleic acid goes beyond the scope of this syndrome. Essential fatty acids have structural functions as integral part of membrane phospholipids and dynamic functions as precursors of prostaglandins. On account of their structural function, the essential fatty acids influence the fluidity of biomembranes and the activity of membrane-bound enzymes and receptor systems. Certain physiological effects of dietary linoleic acid would be explained via this mechanism. Moreover linoleic acid is known to regulate the endogenous prostaglandin biosynthesis. Though incomplete, the knowledge gained fully justifies the application of preventive measures proposed by numerous expert committees for groups of populations with a high rate of atherosclerosis.