Docosahexaenoic acid

Docosahexaenoic acid (DHA) is an omega−3 fatty acid that is an important component of the human brain, cerebral cortex, skin, and retina. It is given the fatty acid notation 22:6(n−3). It can be synthesized from alpha-linolenic acid or obtained directly from maternal milk (breast milk), fatty fish, fish oil, or algae oil. The consumption of DHA (e.g., from fatty fish such as salmon, herring, mackerel and sardines) contributes to numerous physiological benefits, including cognition. As a component of neuronal membranes, the function of DHA is to support neuronal conduction and to allow the optimal functioning of neuronal membrane proteins (such as receptors and enzymes).

Structurally, DHA is a carboxylic acid (-oic acid) with a 22-carbon chain (docosa- derives from the Ancient Greek for 22) and six (hexa-) cis double bonds (-en-); with the first double bond located at the third carbon from the omega end. Its trivial name is cervonic acid (from the Latin word cerebrum for "brain"), its systematic name is all-cis-docosa-4,7,10,13,16,19-hexa-enoic acid.

In organisms that do not eat algae containing DHA nor animal products containing DHA, DHA is instead produced internally from α-linolenic acid, a shorter omega−3 fatty acid manufactured by plants (and also occurring in animal products as obtained from plants). Limited amounts of eicosapentaenoic and docosapentaenoic acids are possible products of α-linolenic acid metabolism in young women and men. DHA in breast milk is important for the developing infant.