Immunological Aspects of Human Milk

The general decline in breastfeeding in most parts of the world has become a major health concern in view of the many physiological, biochemical, psychological, cultural, and economic benefits of breastfeeding for a few months after birth. A review of the immunologic aspect of breastfeeding shows that a spectrum of interacting specific and nonspecific antimicrobial resistance factors found in the human milk (e.g., physicochemical properties, immunoglobulins, iron-binding protein, interferon, polymorphonuclear leukocytes, and macrophages) are responsible for the lowered incidence of infections, particularly gastrointestinal and respiratory infections, allergic disorders (e.g., infantile eczema), necrotizing enterocolitis, and sudden infant death syndrome among breastfed babies. Possible disadvantages of breastfeeding are 1) poliovirus antibodies in human milk may interfere with live attenuated poliovirus vaccine; and 2) possible infection of breastfed infant with microorganisms found in human milk (e.g., Hepatitis B surface antigen and rubella virus). In view of the significant advantages of breastfeeding for the infant, breastfeeding all newborns during the 1st year of life is recommended.