Breast feeding and biological development.
The superiority of human milk as compared with milk of other origin for the feeding of newborns, term or preterm, can be analysed in terms of biological development related to digestive, metabolic and excretory functions during foetal and postnatal life. The macro- and micro-anatomical developments of the intestine are complete in the 6th foetal month. The brush border and some of its enzymes (saccharase-isomaltase) exist already from the 6th foetal week, whereas other enzymes (lactase and intracellular transport enzymes) appear much later. The major gastric and pancreatic enzymes, as well as the synthesis of biliary acids, do not reach maturity until after birth. Several metabolic functions, e.g. the synthesis of cystine from methionine, of tyrosine from phenylalanine, and of urea from ammonia, are still limited at the time of birth. The capacity for excretion of sodium, the osmotic urinary load, and hydrogen ions is suboptimal, especially in the prematurely born. All these circumstances imply that human milk, with its protective properties, represents optimal adaptation to the needs of the child in the perinatal period.
D000222:Adaptation, Physiological; D001940:Breast / Q000502:physiology; D001942:Breast Feeding; D004064:Digestive System / Q000196:embryology / Q000201:enzymology / Q000254:growth & development*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007668:Kidney / Q000196:embryology / Q000254:growth & development*; D008660:Metabolism; D008895:Milk, Human; D011247:Pregnancy