Omega-3 is an essential fatty acid for humans due to the fact that the human body is not capable of producing the fats. This means that we must supplement omega-3 fats through supplements or diet. Omega-3 fatty acids consist of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA). Both eicosapentaenoic acid and docosahexaenoic acid are typically found in fatty fish like salmon. On the other hand, alpha-linolenic acid is typically found in non-animal sources, such as, flaxseed, walnuts, and soybeans. Because alpha-linolenic acid is derived from plant sources, such as flax, vegetarians often exclusively use flax seed oil as a source of omega-3 even though, sadly, it doesn’t contain within it EPA or DHA. Humans are able to convert alpha-linolenic acid into eicosapentaenoic acid then, subsequently, into DHA, but this process is altogether very inefficient. This is partly because the enzyme that turns ALA into eicosapentaenoic acid is rate limiting, because of the fact that the same protein also chemically binds to omega-6 fatty acids (thus, the problem is significantly worse if your diet is high in omega-6).