Essential fatty acid is ?

The three polyunsaturated fatty acids (PUFAs), namely, linoleic acid, linolenic acid, and arachidonic acid are called essential fatty acids.They are called essential fatty acids because human beings require these fatty acids but cannot synthesize them.Humans lack the enzymes to introduce double bonds at carbon atom beyond C9 in the fatty acid chain.Hence, human cannot synthesize linolenic acid and linolenic acid having double bonds beyond C9.Arachidonic acid can be synthesized from linoleic acid. Therefore, in deficiency of linoleic acid, arachidonic acid also becomes essential fatty acids.Therefore linoleic acid is the most impoant essential fatty acid as it serves as a basis for the production of other EFA.