Lack of response to amino acid supplements by preadolescent girls

Abstract
Two replicate 20-day studies were conducted with 32 preadolescent girls. The subjects were fed a diet formulated to simulate one of low income southern families. Although the protein in the diet was supplied primarily by cereals and legumes, supplements of lysine, threonine, and methionine, the amino acids calculated to be most limiting, failed to improve nitrogen utilization. Widespread fortification of foods with amino acids is not justified on the basis of these findings.