What is meant by complete and incomplete when talking about amino acids?

Question

Connor Abernathy · Accepted Answer

This centres around the essential amino acids, as explained below.

The body requires nine of the twenty amino acids it uses to make proteins—known as the "essential" amino acids—to be present in one's diet because the body is unable to produce the other nine. A food item classified as complete protein contains all nine essential amino acids; if any of the essential acids are absent, the protein in the food item is considered incomplete. A vegetarian has to be careful to choose a variety of foods to ensure they get all the essential amino acids because, as far as I know, all animal-based proteins are complete, but no plant-based protein is.

Madeline Andrews · Answer

undefined Whereas incomplete amino acids are deficient in one or more essential amino acids, complete amino acids have all the essential amino acids required for protein synthesis.

Piper Anderson · Answer

undefined Complete amino acids are those that the human body can produce on its own, while incomplete amino acids are those that must be obtained from the diet. In other words, complete amino acids are synthesized internally, while incomplete amino acids must be consumed through food sources.