Polyunsaturated fatty acids

Long-chain carboxylic acids bearing two or more carbon–carbon double bonds, grouped into the omega-6 family (notably linoleic acid) and the omega-3 family (α-linolenic acid, EPA, DHA). Linoleic and α-linolenic acids are essential nutrients that humans cannot synthesize, so they must come from foods such as vegetable oils, nuts, seeds, and oily fish. Intakes of polyunsaturated fatty acids, particularly as replacements for saturated fat, are linked to lower risk of cardiovascular disease through effects on blood lipids and membrane function. Food technologists value them for nutrition claims but must manage their high susceptibility to oxidation, which drives rancidity in oils and finished foods unless controlled with antioxidants and oxygen-barrier packaging.