High Quality Content by WIKIPEDIA articles! Essential fatty acids, or EFAs, are fatty acids that cannot be constructed within an organism (generally all references are to humans) from other components by any known chemical pathways, and therefore must be obtained from the diet. Only 2 EFA's exist Alpha Linolenic Acid and Linoleic Acid The term refers to fatty acids involved in biological processes, and not those which may just play a role as fuel. As many of the compounds created from essential fatty acids can be taken directly in the diet, it is possible that the amounts required in the diet (if any) are overestimated.[citation needed] It is also possible they can be underestimated as organisms can still survive in non-ideal, malnourished conditions. There are two families of EFAs: -3 (or omega-3 or n 3) and -6 (omega-6, n 6). Fats from each of these families are essential, as the body can convert one omega-3 to another omega-3, for example, but cannot create an omega-3 from omega-6 or saturated fats.