Protein and amino acids1

Abstract

The historical discovery of nitrogen in animal tissues and its association with protein and amino acids is described. Important roles of proteins in body structure, as enzymes and hormones, and in immunity and nutrient transport are characterized. Details of protein digestion and absorption are briefly presented. Those dietary amino acids found to be indispensable, conditionally indispensable, and dispensable are identified. A source of information on concentrations of protein and amino acids in food is given, and systems for evaluating protein quality are described. Recommended dietary allowances for protein and indispensable amino acids are summarized.