ROLE OF OMEGA-3-FATTY-ACIDS IN HEALTH AND DISEASE

Dietary lipid interventions have an important role in modulating the onset of autoimmunity, cardiovascular diseases and cancer. Many studies carried out in the past have established the adverse effects of saturated fats in humans and in animal models. Based on these adverse effects, the consumption of vegetable oils containing both monounsaturated omega (omega)-9 and polyunsaturated fatty acids (rich in 18:2 omega-6) is rising significantly in the United States. The increased consumption of many vegetable oils particularly of omega-6 series is however to be viewed as pro-inflammatory and is suspected as one of the possible causes for the gradual rise in certain malignant tumors, rheumatoid arthritis and autoimmune diseases primarily due to the increased production of pro-inflammatory cytokines although its increased usage has reduced cardiovascular disease nearly 30% in the United States. Diets based on omega-6 enriched oils can increase the level of linoleic acid in tissue phosphoglycerides and are able to reduce cholesterol levels, yet these lipids usually tend to elevate excessive arachidonic acid (20:4 omega-6) levels. In contrast, omega-3 fatty acid-enriched fish oil (FO) and/or omega-3 precursors from certain vegetable oils (linolenic acid, 18:3 omega-3) are found to provide protection against cardiovascular disease, rheumatoid arthritis, cancer and possibly against the severity of viral infections. Nutritional modification of cellular functions by dietary lipids with a balanced ratio of omega-6 and omega-3 fatty acids offers an attractive avenue to correct, modify and/or prevent many patho-physiological processes in health and disease state and to reduce toxicity of drugs in many patients. The mediation of such effects is thought to be primarily achieved through alterations of cellular membranes composition and other endogenous lipid stores which may modify the functional activity of various receptors on plasma membranes. In summary, the protective effects of omega-3 lipids have been explained based on changes in eicosanoid synthesis and the reduced risk of sudden death from cardiac arrhythmia, increased protection from ischemic myocardium, improved myocardial function and reduction of other cardiovascular and autoimmune disease risks. However, well-designed studies are still required to further define the key role of both combination of omega-6 and omega-3 fatty acids, from marine and vegetable sources, both as a supplement to infant nutrition specifically for optimizing the development of cognitive function, and also as preventive measure for reducing the incidence of diseases of aging in rapidly growing elderly populations.