University of Illinois scientists have recently learned a new way to observe the different effects that breast and formula milk have on developing babies. The results confirm and give greater clarity about the already common understanding that breast milk is ideal. “For the first time, we can see that breast milk induces genetic pathways that are quite different from those in formula-fed infants. Although formula makers have tried to develop a product that’s as much like breast milk as possible, hundreds of genes were expressed differently in the breast-fed and formula-fed groups,” said Sharon Donovan, a University of Illinios professor of nutrition. “The intestinal tract of the newborn undergoes marked changes in response to feeding. And the response to human milk exceeds that of formula, suggesting that the bioactive components in breast milk are important in this response,” she added “An infant’s gut has to adapt very quickly. A new baby is coming out of a sterile environment, having received all its nutrients intravenously through the placenta. At that point, babies obviously must begin eating, either mother’s milk or formula. “They also start to become colonized with bacteria, so it’s very important that the gut learns what’s good and what’s bad. The baby’s body needs to be able to recognize a bad bacteria or a bad virus and fight it, but it also needs to recognize that even though a food protein is foreign, that protein is okay and the body doesn’t want to develop an immune response to it,” she said. It’s during this stage that if something goes wrong babies can develop inflammatory bowel disease, food allergies, and even asthma. “We’re very interested in frequent sampling at this early period of development,” she added. Next on the list for Donovan is to learn how bacteria in the gut differ in formula- and breast-fed babies, which should be feasible due to this technique. “Now we’ll be able to get a complete picture of what’s happening in an infant — from the composition of the diet to the microbes in the gut and the genes that are activated along the way.” .