Which fatty acid is essential and must be obtained from the diet?

Which fatty acid is essential and must be obtained from the diet?

• A. Linoleic acid
• B. Palmitic acid
• C. Oleic acid
• D. Stearic acid

Answer: (A)

Essential fatty acids are fats the body cannot make in sufficient amounts and must come from the diet. Linoleic acid is one of these: humans lack enough desaturase enzymes to produce it endogenously, so it becomes essential to obtain from foods. It’s an omega-6 fatty acid (18:2, n-6) that serves as a precursor to longer-chain fatty acids and signaling molecules important for membranes and physiology. The other fatty acids listed can be synthesized by the body—palmitic and stearic are saturated fats produced in lipogenesis, and oleic can be formed by desaturating stearic acid—so they aren’t required to be consumed as essential nutrients.

Essential fatty acids are fats the body cannot make in sufficient amounts and must come from the diet. Linoleic acid is one of these: humans lack enough desaturase enzymes to produce it endogenously, so it becomes essential to obtain from foods. It’s an omega-6 fatty acid (18:2, n-6) that serves as a precursor to longer-chain fatty acids and signaling molecules important for membranes and physiology. The other fatty acids listed can be synthesized by the body—palmitic and stearic are saturated fats produced in lipogenesis, and oleic can be formed by desaturating stearic acid—so they aren’t required to be consumed as essential nutrients.