Omega-6/omega-3 ratio and brain-related functions.

While the general public typically perceives lipids and fats as 'harmful' components of the diet (as in the popular slogan: 'fat kills'), the scientific story is in fact very different. Among the major scientific research efforts of the recent period, in the area of neuroscience, we find the recognition of the 'essential fatty acids' (EFA). The profound effects of various fatty acids, and equally profound effects of their deficits, are appreciated by a variety of disciplines, including (but not necessarily limited to) lipid biochemistry, physiology, nutrition, psychology, psychiatry, and neurosciences at large. Recently, the issue of lipids, and fatty acids ratio in diets, became an important issue. Simopoulos [1] showed the historical shift from a 'balanced' omega–6 and omega–3 ratio diet, towards a marked and significant reduction in the omega–3 intake, and explained that the general 'Western diet' of today can in actual fact be considered an omega–3-deficient diet. Her concern is that this 'deficiency' may lead to coronary heart disease and high cancer mortality. Linoleic acid (LA; omega–6; ␻6; 18:2␻6) is the parent fatty acid of the omega–6 group. Linoleic acid must be supplied to the body by the diet, because the body is unable to synthesize it. All other members of the omega–6 group are derivatives of LA. Similarly, the parent compound of the omega–3 group is alpha-linolenic acid (ALA, omega–3, ␻3, 18:3␻3). All other members of the omega–3 group are merely derivatives of ALA, and together they form the polyunsaturated fatty acids (PUFA). In each group, the derivatives can convert to longer chain fatty acids by using two mechanisms: desaturation and elongation.