Essential fatty acid interactions

The effects on humans of the ω-3 (omega-3) and ω-6 (omega-6) essential fatty acids (EFAs) are best characterized by their interactions; they cannot be understood separately.

Arachidonic acid (AA) is a 20-carbon ω-6 conditionally essential fatty acid. It sits at the head of the "arachidonic acid cascade" – more than 20 different signalling paths that control a wide array of bodily functions, but especially those functions involving inflammation, cell growth and the central nervous system. Most AA in the human body derives from dietary linoleic acid (another essential fatty acid, 18:2 ω-6), which is derived from nuts, seeds, vegetable oils and animal fats.

In the inflammatory response, two other groups of dietary essential fatty acids form cascades that parallel and compete with the arachidonic acid cascade. EPA (20:5 ω-3) provides the most important competing cascade. It is ingested from oily fish, and algae oil or derived from dietary alpha-linolenic acid found in, for instance, walnuts, hemp oil and flax oil. DGLA (20:3 ω-6) provides a third, less prominent cascade. It derives from dietary GLA (18:3 ω-6) found in, e.g. borage oil. These two parallel cascades soften the inflammatory promoting effects of certain eicosanoids made from AA. Low dietary intake of these less inflammatory promoting essential fatty acids, especially the ω-3s, is correlated with a variety of inflammation-related diseases.

...
Wikipedia