Breast milk is an extremely complex and highly variable biofliud that has evolved to nourish infants and protect them from disease whilst their own immune system matures. The composition of human breast milk changes in response to many factors, matching the infants requirement according to its age and other characteristics.~Therefore, the composition of breast milk is widely believed to be specifically tailored by each mother to precisely reflect the requirements of her infant.~Human milk is uniquely suited to the human infant, both in its nutritional composition and in the non-nutritive bioactive factors that promote survival and healthy development.~Breast milk contains over 400 different proteins which perform a variety of functions; providing nutrition, possessing antimicrobial and immunomodulatory activities, as well as stimulating the absorption of nutrients.~The immune system of preterm infants is immature, placing them at increased risk for serious immune-related complications.~Human milk provides a variety of immune protective and immune maturation factors that are beneficial to the preterm infants poorly developed immune system. The most studied immune components in human milk include antimicrobial proteins, maternal leukocytes, immunoglobulins, cytokines and chemokines, oligosaccharides, gangliosides, nucleotides, and long-chain polyunsaturated fatty acids. There is growing evidence that these components contribute to the lower incidence of immune-related conditions in the preterm infant. Therefore, provision of these components in human milk, donor milk, or formula may provide immunologic benefits.~The effects of breast milk and breastfeeding on neurodevelopment may be quite different in very preterm infants than in those born at full term. Nutritionally, breast milk is considered the optimal food for full term infants. But preterm infants require fortification to match third trimester nutrient accretion rates.
Breast milk is an extremely complex and highly variable biofliud that has evolved to nourish infants and protect them from disease whilst their own immune system matures. The composition of human breast milk changes in response to many factors, matching the infants requirement according to its age and other characteristics.