Which are essential fatty acids and their primary functions?

• A. Linoleic acid (omega-6) and alpha-linolenic acid (omega-3); essential for cell membranes and precursors to signaling molecules.
• B. Palmitic acid and stearic acid.
• C. Oleic acid and linoleic acid.
• D. Arachidonic acid and palmitoleic acid.

Answer: (A)

Essential fatty acids are fats the body cannot make in sufficient amounts, so they must come from the diet. Linoleic acid (omega-6) and alpha-linolenic acid (omega-3) are the two essential fatty acids. They are fundamental building blocks for cell membranes, helping to maintain membrane structure and function, which affects things like fluidity and how proteins in the membrane work. They also serve as starting points for making signaling molecules (eicosanoids) that regulate inflammation, blood flow, and other vital processes. The body can convert these essential fats into longer-chain polyunsaturated fatty acids, such as arachidonic acid and EPA/DHA, but that conversion is limited, which is why intake of the essential forms matters. The other fats listed are either saturated or monounsaturated and can be synthesized by the body, so they aren’t classified as essential. This makes linoleic and alpha-linolenic acids the correct answer.