Which of the following is NOT considered an Omega-3 fatty acid?

Omega-3 fatty acids are a specific class of polyunsaturated fatty acids recognized for their beneficial health properties. The classification of fatty acids as omega-3 depends on the position of the first double bond from the methyl end (omega end) of the carbon chain. Omega-3 fatty acids typically have their first double bond at the third carbon from that end.

Eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA) are all classified as omega-3 fatty acids. EPA and DHA are often found in fatty fish and algae, while ALA is typically obtained from plant sources like flaxseeds and walnuts. Their roles in promoting heart health and reducing inflammation are well established in nutritional science.

In contrast, arachidonic acid does not fit this classification as it is considered an omega-6 fatty acid. Arachidonic acid has its first double bond at the sixth carbon from the methyl end, distinguishing it from omega-3s. This structural difference leads to different physiological effects, particularly in the context of inflammatory processes and cell signaling.

Thus, the identification of arachidonic acid as not being an omega-3 fatty acid is based on its distinct