Human Milk: Its Components and Their Immunobiologic Functions

Whereas a neonate is born is sterile, immediate exposure to its mother's mucosal surfaces allows it to acquire microflora, which plays an important role in defense against potential pathogens. This initial stimulus helps the immature immune system of the newborn to develop the capacity to respond with specific immunologic tolerance while avoiding the development of allergic and autoimmune disease. Breast-feeding provides nutritional and developmental, along with anti-infectious, advantages to the infant. The significant protection conferred by breast-feeding against varied infections such as acute and prolonged diarrhea, neonatal septicemia, respiratory tract infections, acute and recurrent otitis media, and urinary tract infections is observed worldwide. Human breast milk contains numerous components, including antibodies, cytokines, hormones, enzymes, and major proteins with multiple activities (microbicidal, tumoricidal, anti-inflammatory, autoimmune, etc.). Breast-feeding can strikingly reduce infant mortality, as well as the fertility of the breast-feeding mother. In this manner, breast-feeding provides significant benefits for lactating mothers and their offspring, in addition to society as a whole. © 2015 Elsevier Inc. All rights reserved.