Breast Milk Promotes a Different Gut Flora Growth Than Infant Formulas
New findings explain how breast milk, but not infant formula, fosters colonies of microbiotic flora in a newborn's intestinal tract that aid nutrient absorption and immune system development
The benefits of breast milk have long been appreciated, but now scientists at Duke University Medical Center have described a unique property that makes mother's milk better than infant formula in protecting infants from infections and illnesses
The finding is published in the August issue of the journal Current Nutrition & Food Science.
"This study is the first we know of that examines the effects of infant nutrition on the way that bacteria grow, providing insight to the mechanisms underlying the benefits of breast feeding over formula feeding for newborns," said William Parker, PhD, associate professor of surgery at Duke and senior author of the study. "Only breast milk appears to promote a healthy colonization of beneficial biofilms, and these insights suggest there may be potential approaches for developing substitutes that more closely mimic those benefits in cases where breast milk cannot be provided."
Earlier studies have shown that breast milk
lowers the incidence of diarrhea, influenza
and respiratory infections during infancy,
while protecting against the later development
of allergies, type 1 diabetes, multiple sclerosis
and other illnesses.
As scientists have learned more about
the role intestinal flora plays in health,
they have gained appreciation for how
an infant's early diet can affect
this beneficial microbial universe.
In their study, the Duke researchers grew bacteria in samples of infant formulas, cow's milk and breast milk. For the infant formula, the researchers used three brands each of popular milk- and soy-based products, and they purchased whole milk from the grocery store. Breast milk was donated and processed to separate different components, including proteins, fats and carbohydrates. They also tested a purified form of an antibody called secretory immunoglobulin A (SIgA), which is abundant in breast milk and helps establish an infant's immune system.
The infant formulas, the milk products and the SIgA were incubated with two strains of E. coli bacteria necessary early inhabitants of the gut that are helpful cousins to the dangerous organisms associated with food poisoning.
Within minutes, the bacteria began multiplying in all of the specimens, but there was an immediate difference in the way the bacteria grew.
In the breast milk, bacteria stuck together
to form biofilms -- thin, adherent layers of bacteria
that serve as a shield against pathogens and infections.
Bacteria in the infant formula and cow's milk
proliferated wildly, but it grew as individual organisms
that did not aggregate to form a protective barrier.
The bacteria in SIgA had mixed results,
suggesting that this antibody by itself isn't enough
to trigger the beneficial biofilm formation.
Parker: "Knowing how breast milk conveys its benefits could help in the development of infant formulas that better mimic nature. This could have a long-lasting effect on the health of infants who, for many reasons, may not get mother's milk."
Parker said additional studies should explore why human whey has the clumping effect on the bacteria, and whether it has a similar effect on strains of bacteria other than E. coli.
Gabriela M. Maradiaga Panayotti, M.D., co-director of the newborn nursery for Duke Children's and Duke Primary Care: "This study adds even more weight to an already large body of evidence that breast milk is the most nutritious way to feed a baby whenever possible. We know that babies who receive breast milk have better outcomes in many ways, and mother who breast feed also have improved health outcomes, including decreased risks of cancer. Whenever possible, promoting breast feeding is the absolute best option for mom and baby."
In addition to Parker, study authors include Angela Q. Zhang, S.Y. Ryan Lee, Melat Truneh and Mary Lou Everett.
The study was supported in part by the Fannie E. Rippel Foundation and a pre-college research fellowship from the Howard Hughes Medical Institute to Zhang and Lee.
Study authors reported no conflicts of interest.
Original article: http://www.dukehealth.org/health_library/news/breast-milk-promotes-a-different-gut-flora-growth-than-infant-formulas