Which of the following is true about essential amino acids?

Essential amino acids are those that cannot be synthesized by the human body and therefore must be obtained through dietary sources. There are a total of nine amino acids classified as essential: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. These amino acids play a critical role in various bodily functions, including protein synthesis, the production of hormones, and the maintenance of immune function.

The body relies on the intake of essential amino acids through food, particularly from sources such as meat, eggs, dairy, and certain plant-based proteins (like quinoa and soy). Unlike non-essential amino acids, which the body can produce, essential amino acids must be provided by the diet to ensure proper physiological function and support overall health.