Breast is Best for Baby Bacteria

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The human gastrointestinal tract is home to many species of bacteria, some of which play a critical role in nutrient absorption of digested food. In babies, gut flora not only aids digestion, but also provides immunity and protection from disease. Researchers recently report that the bacteria in the intestinal tract of infants drinking breast milk may have an added advantage over gut bacteria in babies fed formula—the formation of a protective lining of biofilm that protects a baby from pathogens.

Mounting evidence has shown that breast milk is best for a baby’s development both physiologically and immunologically. Some research supports the belief that infants drinking breast milk not only benefit early in life, but also later on as adults with a decreased risk of Type I diabetes and other illnesses.

Exactly how breast milk is best remains unclear, but researchers are coming closer to finding answers to this question. One route of investigation is looking at how that breast milk may confer immunity through immune system modulating agents found in breast milk such as cytokines and growth factors that act at the level of the gastrointestinal mucosa. Another route is the effect that micro flora (gut bacteria) plays on an infant’s health.

In an article to be published in the journal Current Nutrition & Food Science, researchers investigated whether choosing formula over breast milk for feeding an infant can affect strains of gut bacteria that have already been identified as being important to the health of a baby. To test the choice of infant feeding on bacteria, researchers collected samples of human breast milk, cow milk purchased at the market, and 3 brands of infant formula and incubated all samples with two strains of E. coli bacteria common in an infant’s GI tract.

What they discovered was that while all samples tested supported growth of the bacterial strains, only the samples of breast milk resulted in bacteria that naturally formed into biofilms. The bacteria grown in cow milk and in formula proliferated in separate, free-floating planktons (single-celled organisms) that did not aggregate into a biofilm that could possibly line an infant’s GI tract.

Biofilms are typically described as a defense mechanism for a strain of bacteria that find safety not only in numbers, but in community. Basically, a biofilm forms when single bacteria attach relatively near each other on a tissue surface and are able to communicate together to begin secreting biochemicals and forming a shared slime-like polysaccharide complex that covers the bacteria and protects them from viruses, competing bacteria and medications. Many diseases are attributed to the formation of biofilms by harmful bacteria such as endocarditis when a biofilm forms on heart valves. A common example of a biofilm is the film of plaque that covers teeth and causes tooth decay and gum disease.

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However, not all bacteria are harmful and therefore some biofilms may be beneficial to the host as well as the bacteria. In this case, the good bacteria in an infant’s gut may play an important role with protective biofilm formation in the gastrointestinal tract that prevents harmful pathogens from infecting or damaging the mucosa lining the infant’s gut.

According to a press release issued by Duke University Medical Center, "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."

While further research is needed to determine how infant formula can be fortified with healthy bacteria that can mimic breast milk, experts agree that breast is best for a baby and its bacteria.

"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," said Gabriela M. Maradiaga Panayotti, M.D., co-director of the newborn nursery for Duke Children's and Duke Primary Care. "We know that babies who receive breast milk have better outcomes in many ways, and mothers 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."

Image Source: Courtesy of Wikipedia

References:

DukeHealth.org

YouTube Video “What are bacterial biofilms? A six-minute montage”

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