Omega-6 Fatty Acids

Omega-6 fatty acids contain their last double bond in the alkenic chain six carbon atoms from the fatty acid omega end and are generally essential fatty acids for humans. This means that they cannot be synthesized by simple elongation or desaturation steps of palmitic (FA 16:0), stearic (FA 18:0), or oleic acid (FA 18:1) by our organism and consequently have to be taken up by diet. The starting point for synthesis of most omega-6 fatty acids is linoleic acid (FA 18:2) which is sequentially elongated and desaturated into other long chain and very long chain omega-6 fatty acids. Linoleic acid is the most commonly found omega-6 fatty acid in plants and animals but can only be produced by plants. The major sources are sunflower and soybean with up to 50 % of linoleic acid.

γ-Linolenic acid (FA 18:3 ω-6) is the first desaturation product of linoleic acid and therefore an intermediate at the pathway from linoleic acid to higher omega-6 fatty acids. It can be found in substantial proportions...