What Immunity Is Passed on in a Mother's Milk?

Colostrum and Immunoglobulin A

• Colostrum is the milk your body produces in the first few days after childbirth. Immunoglobulin A, or IgA, is a substance that helps protect your baby from infections as well as allergies. IgA coats the lining of her intestines, which are still immature and cannot handle the absorption of many food molecules. A newborn is exposed to germs and other foreign substances, and colostrum -- which is rich in IgA -- offers general immunity and extra protection just when she most needs it.

Antibodies

• When humans become infected with germs such as bacteria or viruses, their bodies develop immunity by producing antibodies to the particular germ. A mother who develops a cold while breastfeeding, for example, develops antibodies that are passed to her baby through breast milk. The antibodies protect her baby from the virus that caused that particular cold. If the baby catches the cold, she is likely to have only a mild illness. The American Academy of Pediatrics reports that breast-fed babies who received no nourishment except breast milk for the first four months are less likely to need hospitalizations for croup, bronchiolitis or pneumonia than babies fed formula.

Infections and Cancer

• The AAP notes that breast-fed babies are less likely to develop ear infections, urinary tract infections and spinal meningitis. They are also less likely to suffer from gastrointestinal problems such as vomiting and diarrhea or from pneumonia. Breast feeding may also help prevent or lessen the risk of allergies such as eczema and asthma, which result from an immune system reaction to foods and other substances. In addition, the AAP says babies who are breastfed for at least six months do not develop childhood acute leukemia or lymphoma at the same rate as babies fed formula.

Other Infections

• Most adults catch a variety of diseases, beginning in childhood. Mumps, measles and chickenpox, for example, are viral diseases that were once called ̶0;usual childhood diseases̶1; because they were so common. Although vaccinations are now available, some children still become ill with these infections. From the baby̵7;s perspective these infections are beneficial, because a mother who has had chickenpox, for example, will pass on the antibodies for chickenpox in her breast milk. In addition, pediatrician William Sears writes that breast milk protects babies from diseases such as Type B influenza, infant botulism, cholera, salmonella and E. coli infections.