An omega-6 fatty acid is a
polyunsaturated fatty acid with its first double bond at the sixth carbon from the omega (methyl) end. The primary essential omega-6 fatty acid is linoleic acid (LA), which must be obtained from the diet because the body cannot synthesize it. The body can convert LA into arachidonic acid (ARA), a longer-chain omega-6 fatty acid that is an important component of cell membranes and a precursor to signaling molecules called eicosanoids. These eicosanoids help regulate inflammation, immune responses, blood clotting, and blood-vessel function. Some ARA-derived eicosanoids promote inflammation, while others have different or opposing effects, so ARA should not simply be described as an "inflammatory" fatty acid.