Breast Milk is Best for Babies, Here's Why
Scientists have long known that breast milk is best for babies because it provides components that protect the immune system and help reduce an infant’s risk for developing infections. What researchers did not know was how and why breast milk specifically protects infants, but now they are closer to an answer.
Scientists at the University of Illinois and their colleagues from Texas A&M University have been able to track specific genes in an infant’s intestinal tract. They found that in newborns, this system undergoes significant changes in response to what the infant is fed.
Sharon Donovan, a University of Illinois professor of nutrition, noted that “for the first time, we can see that breast milk induces genetic pathways that are quite different from those in formula-fed infants.” She went on to explain that “the response to human milk exceeds that of formula, suggesting that the bioactive components in breast milk are important in this response.”
The Centers for Disease Control and Prevention has stated in Healthy People 2010 that “Breast milk is widely acknowledged as the most complete form of nutrition for infants, with a range of benefits for infants’ health, growth, immunity and development.” The depth and breadth of those benefits include but are not limited to breast-fed infants being more resistant to disease and infection early in life than formula-fed children, including respiratory infections, ear infections, and diarrheal infections; and breast-fed children being less likely to develop certain diseases later in life, including juvenile diabetes, heart disease, cancer, and multiple sclerosis.
Breast-fed infants also are less likely to be a victim of sudden infant death syndrome, and studies show that infants fed breast milk are significantly less likely to develop allergies. Breast milk also can help an infant develop a normal immune response to vaccines.
In the new study, intestinal gene expression was explored in 22 healthy infants, 12 who were being breast-fed and 10 who were receiving formula. The investigators isolated intestinal cells collected from the infants’ stools, which the mothers collected from their babies at ages one, two, and three months. Scientists isolated and turned their attention to RNA to uncover a gene expression or signature and found that breast milk invoked different genetic responses than did formula.
A healthy intestinal environment is critical for infants, whose immune systems are far from being mature. Donovan explained that “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.” If something goes wrong during this early stage of development, infants can develop a variety of conditions, including food allergies, asthma, and inflammatory bowel disease.
The findings of this study will allow scientists to form a more complete idea of the activity in an infant’s gut and how the bacteria differ in breast-fed and formula-fed infants. Although the makers of infant formula have attempted to make products that are close to breast milk, Donovan noted they found that “hundreds of genes were expressed differently in the breast-fed and formula-fed groups.” Breast milk is still the best milk for babies.
Centers for Disease Control and Prevention Healthy People 2010
Natural Resources Defense Council
University of Illinois College of ACES