Human milk is a very complex living fluid which includes proteins, carbohydrates, lipids, cells and other biologically important components. These milk components interact with each other and their environment (the infants gut) with the final result being that breast-milk feeds and protects the newborn.

Most physicians presumed that breast-fed children fared better simply because milk supplied directly from the breast is free of bacteria. Yet even infants who receive sterilized formula suffer from more meningitis and infection in the gut, ear, respiratory tract and urinary tract. All newborns receive some coverage in advance of birth. During pregnancy the mother passes antibodies to her fetus through the placenta. These proteins and the added protection of breast-milk circulate in the infant’s blood for weeks to months after birth and because the mother makes antibodies to pathogens in her environment, the baby receives the protection it most needs against infectious agents it is most likely to encounter in the first few weeks of life.

It protects the infants against infection until they can protect themselves. Once foods other than breast-milk are introduced, the established microbes are ready to adapt and utilize the nutrients from a new source and should be able to maintain a healthy balance.

Given the importance of beneficial bacteria for a healthy baby it is essential that the mother’s health is ensured, preferably before pregnancy. A healthy mother is more likely to deliver a healthy baby.