Fatty Acids and the Immune System

Synonyms

DHA; Docosahexaenoic acid; Eicosapentaenoic acid; EPA; Fats; Lipids; Polyunsaturated fatty acids; PUFA

Definition

Fatty acids are hydrocarbon chains, which can be saturated, monounsaturated, or polyunsaturated (PUFA). There are two essential fatty acids, linoleic and α-linolenic acid, which cannot be synthesized de novo in animal cells. Linoleic acid is an n-6 PUFA present in large quantities in many vegetable oils; it can be described by its shorthand notation of 18:2n-6, which refers to an 18-carbon fatty acid with two double bonds, the first of which is on carbon atom 6 from the methyl end. α-Linolenic acid is an n-3 PUFA present in green leafy vegetables and some seed oils (e.g., linseed oil); its shorthand notation is 18:3n-3, describing an 18-carbon fatty acid with three double bonds, the first being positioned at carbon atom 3 from the methyl end. Both essential fatty acids can be further elongated and desaturated in animal cells forming the n-6 and n-3 families of PUFA...