Polyunsaturated fatty acids n-3: new data on heart disease, cancer, immune resistance and mental depression

Attention to the role of n-3 long-chain polyunsaturated fatty acids from fish (n-3) in human health has remarkably increased during recent decades. Many clinical and epidemiologic studies have shown a positive role for n-3 in cardiovascular diseases, cancer, infant development and more recently, in various mental illnesses, especially in depression. These fatty acids are known to have pleiotropic effects, especially against hypertriglyceridemia and platelet aggregation. These may be mediated through several distinct mechanisms, including alterations in cell membrane composition and function, gene expression, or eicosanoid production. A number of authorities have recently recommended an increase in intakes of n-3 by the general population, because "western" diets are deficient in n-3 and have excessive amounts of n-6 fatty acids. The target EPA + DHA consumption was recommended to be at least 500 mg/day for individuals without heart disease and at least 800 to 1000 mg/day for patients with known coronary heart disease. To comply with this recommendation, a variety of food products, most notably eggs, yogurt, milk and spreads have been enriched with n-3. Additional controlled clinical trials are needed to document whether long-term consumption or supplementation with eicosapentaenoic (EPA) or docosahexaenoic (DHA) acids results in better quality of life (Fig. 4, Ref. 47).