<unk> s, or<unk> s, are<unk>  acids that cannot be constructed within an organism from other components (generally all references are to humans) by any known chemical pathways; and therefore must
be obtained from the diet. The term refers to those involved in biological processes, and not<unk>  acids which may just play a role as fuel. As many of the compounds created from<unk> s can be taken directly in the diet, it is possible that the amounts required in the diet (if any) are overestimated. It is also possible they can be underestimated as organisms can still survive in unideal, malnourished conditions.
There are two families of<unk> s: ω-3 (or omega-3 or n-3) and ω-6 (omega-6, n-6.) Fats from each of these families are<unk> , as the body can convert one omega-3 to another omega-3, for example, but cannot create an omega-3 from scratch.
They were originally designated as Vitamin F when they were discovered as<unk>  nutrients in 1923.  In 1930, work by Burr, Burr and Miller showed that they are better classified with the fats than with the vitamins.
Essential fatty acid
Omega-3 fatty acid
Essential amino acid
Unsaturated fat
Short chain fatty acid
Glycolic Acid
Saturated fat
Diol