Hormonally active peptides in human milk

Human milk contains many hormone and hormone‐like peptides. The gastrointestinal tract of newborn infants exhibits lower proteolytic activity than in adults and higher “permeability” for macromolecules. Studies in experimental animals demonstrate that several peptides (epidermal growth factors, insulin‐like growth factor I and bombesin) after orogastric administration exhibit effects on the small intestine and other organs (liver or pancreas). Few studies performed in human neonates suggest a “survival” of epidermal growth factor in their gastric content. Further studies are needed to evaluate the role of milk‐borne hormonally active peptides. This need is stressed by the fact that several of those known to be present in human milk were found to be low or not detectable in infant formulae (epidermal growth factor, insulin‐like growth factor I, insulin, parathyroid hormone‐related peptide).