Breastfeeding mothers often notice that their children are sick less often than children who aren't breastfed. Human milk provides different kinds of defense against disease, including secretory antibodies against specific pathogens. It also contains lactoferrin, which not only is the source of iron for breastfed infants, but also appears to have antibacterial and antiviral properties. Other components in human milk protect infants on a molecular level because their actual shape hinders certain pathogen's access to the infant.
Because human milk has protective qualities, infants who are not breastfed have more emergency room visits, hospitalizations, and treatments with antibiotics. The protective effects extend beyond weaning. (See the table below.)
Human milk offers immunological protection against many chronic diseases. According to Outcomes of Breastfeeding versus Formula Feeding, compiled by Ginna Wall, MN, IBCLC, and Jon Ahrendsen, MD, FAAFP, human milk feeding is associated with less risk of the following diseases: celiac disease, diabetes, multiple sclerosis, sudden infant death syndrome, childhood cancer, autoimmune thyroid disease, appendicitis, osteoporosis, cardiovascular disease, helicobacter pylori infection (associated with gastric ulcers), Crohn's disease, colitis, juvenile rheumatoid arthritis, obesity, tonsillitis, allergies, atopic disease, and asthma. (This comprehensive report can be found at www.lalecheleague.org/docs/Outcomes_of_breastfeeding_June_2007.pdf *.)
The mechanism of these apparent long-term immunologic benefits remains unclear, although theories abound. Human milk contains bioactive components that enhance the growth and development of the human infant.
One gastrointestinal hormone, cholecystokinine (CCK) signals sedation and a feeling of satiation and well-being. During suckling, CCK release in both mother and infant produces a sleepy feeling. The infant's CCK level peaks twice after suckling. The first peak occurs immediately after the feeding. It peaks again 30 to 60 minutes later. The first CCK rise is probably induced by suckling; the second by the presence of milk in the GI tract. The drop of infant CCK levels 10 minutes after a feeding implies a "window" within which the infant can be awakened to feed from the second breast or to reattach to the first side for additional fat-rich milk. Waiting 30 minutes after the feeding before laying the baby down takes advantage of the second CCK peak to help the infant to stay asleep.
* This link updated in May, 2007