Figure. Chemical Structures of ω-3 Fatty Acids α-Linolenic Acid, Eicosapentaenoic Acid, and Docosahexaenoic Acid.

A, α-Linolenic acid (18:3 ω-3) is a carboxylic acid with an 18-carbon (indicated as numbers below the structure) chain and 3 cis double bonds. B, Eicosapentaenoic acid (20:5 ω-3) is a carboxylic acid with a 20-carbon chain and 5 cis double bonds. C, Docosahexaenoic acid (22:6 ω-3) is a carboxylic acid with a 22-carbon chain and 6 cis double bonds. For all 3 structures, the first double bond is located at the third carbon (indicated by the numbers above the structures) from the ω end of the fatty acid chain.