The Current Status of Peptide Absorption

Mammalian intestine does not absorb macromolecules such as proteins and polysaccharides to any significant extent, except for a very short period after birth. These macromolecules are broken down to smaller units in the gastrointestinal tract by the action of digestive enzymes and the smaller units are actively absorbed by the enterocyte. In the case of proteins, the smaller units were thought to be free amino acids.