Which amino acid is considered essential for infants?

Histidine is considered an essential amino acid for infants because their bodies are not able to synthesize it in sufficient quantities to meet metabolic needs. During infancy, adequate intake of histidine is critical for proper growth, development, and the production of various enzymes and proteins. This amino acid plays a vital role in the formation of hemoglobin, the protein in red blood cells that carries oxygen, and is also important for the proper functioning of the immune system.

In contrast, threonine, serine, and tyrosine, while important for overall health, do not share the same classification as essential for infants. For instance, serine can be synthesized by the body, which makes it non-essential. Tyrosine, although important, can be produced from phenylalanine, meaning it doesn't need to be obtained directly from the diet when sufficient phenylalanine is available. This distinction highlights the unique nutritional requirements of infants compared to older children and adults.