ABSTRACT
This chapter discusses the role of the gut in digestion and absorption of protein, the concept of biogenic amines, and the effect of protein form on organ function. Protein is essential for normal cellular function and integrity. It is required for the manufacture of vital cell components which include enzymes and structural proteins. Protein is available in three major forms: free amino acids, peptides or hydrolyzed protein, and intact protein. Enteral nutritional formulas may use these forms of protein alone or in combination. Although many nutritional formulas contain peptides and amino acids, there are significant differences in the content i.e., quantity and quality of both free amino acids and peptides. Most dietary nitrogen is ingested in the form of intact protein. Protein digestion consists of three major phases: a gut lumen phase, a brush border phase, and a cytoplasmic phase. In normal situations, gastric emptying, and not hydrolysis, is rate limiting in the absorption of protein.
