Which fatty acids are essential in the human diet?

Which fatty acids are essential in the human diet?

• A. Linoleic acid (omega-6) and alpha-linolenic acid (omega-3)
• B. Oleic acid (omega-9) and palmitic acid
• C. Arachidonic acid and eicosapentaenoic acid
• D. Stearic acid and myristic acid

Answer: (A)

Essential fatty acids are those the body cannot make and must obtain from food. Humans lack the enzymes to insert the necessary double bonds at the omega-3 and omega-6 positions, so certain polyunsaturated fatty acids must come from the diet. The two that fit this are linoleic acid (an omega-6 fatty acid with 18 carbons and two double bonds) and alpha-linolenic acid (an omega-3 fatty acid with 18 carbons and three double bonds). These serve as starting points for making other long-chain fatty acids in the body, though the conversion to longer-chain forms is limited, so dietary intake is still important. Other fats listed are not required to be consumed because the body can synthesize them or they are not essential. Oleic acid, a monounsaturated omega-9 fatty acid, can be made in the body. Palmitic and stearic acids are saturated fats that the body can synthesize as needed. Arachidonic acid and eicosapentaenoic acid are long-chain fatty acids that can be produced from the essential fatty acids, though they may be provided directly in certain diets; they are not strictly essential on their own.

Essential fatty acids are those the body cannot make and must obtain from food. Humans lack the enzymes to insert the necessary double bonds at the omega-3 and omega-6 positions, so certain polyunsaturated fatty acids must come from the diet. The two that fit this are linoleic acid (an omega-6 fatty acid with 18 carbons and two double bonds) and alpha-linolenic acid (an omega-3 fatty acid with 18 carbons and three double bonds). These serve as starting points for making other long-chain fatty acids in the body, though the conversion to longer-chain forms is limited, so dietary intake is still important.

Other fats listed are not required to be consumed because the body can synthesize them or they are not essential. Oleic acid, a monounsaturated omega-9 fatty acid, can be made in the body. Palmitic and stearic acids are saturated fats that the body can synthesize as needed. Arachidonic acid and eicosapentaenoic acid are long-chain fatty acids that can be produced from the essential fatty acids, though they may be provided directly in certain diets; they are not strictly essential on their own.