Which of the following protein sources does not contain all essential amino acids in appreciable quantities?

Which of the following protein sources does not contain all essential amino acids in appreciable quantities?

• A. Poultry
• B. Eggs
• C. Lentils
• D. Beef

Answer: (C)

Proteins are either complete or incomplete regarding essential amino acids. Complete proteins provide all the essential amino acids in adequate amounts, which animal-derived sources like poultry, eggs, and beef do. Lentils, a legume, are an incomplete protein because they are low in one or more essential amino acids—typically the sulfur-containing ones like methionine. On their own, lentils don’t supply all essential amino acids in appreciable quantities. They can help toward a complete profile when eaten with other plant foods that supplement the lacking amino acids, but by themselves they fall short. That’s why lentils are the correct choice.

Proteins are either complete or incomplete regarding essential amino acids. Complete proteins provide all the essential amino acids in adequate amounts, which animal-derived sources like poultry, eggs, and beef do. Lentils, a legume, are an incomplete protein because they are low in one or more essential amino acids—typically the sulfur-containing ones like methionine. On their own, lentils don’t supply all essential amino acids in appreciable quantities. They can help toward a complete profile when eaten with other plant foods that supplement the lacking amino acids, but by themselves they fall short. That’s why lentils are the correct choice.