Human breast milk has long been considered “liquid gold” among doctors treating premature babies in a neonatal intensive care unit (NICU). Breastfed “premature babies” are, on average, healthier than formula-fed ones. However, why that is true remains a mystery.
New research from the Institute for Genome Sciences (IGS) at the University of Maryland School of Medicine (UMSOM), published online in the journal mBio in June, found that it’s not just the content of breast milk that marks the difference. It’s also how babies digest it.
The research, led by Bing Ma, PhD, Assistant Professor of Microbiology and Immunology at UMSOM and an IGS investigator, discovered a strain of the bacterium Bifidobacterium breve, or B. breve, in the intestines of breastfed infants who received larger volumes of breast milk. than their counterparts. Those premature babies absorbed nutrients better because they developed an intact intestinal wall one week after birth. B. breve was much less common in both formula-fed and breastfed babies with “leaky gut.” Babies with leaky gut do not develop a barrier to protect against bacteria and digested food from entering the bloodstream. For the first time, the team also discovered that the way B. breve metabolizes breast milk keeps breastfed babies healthier and allows them to gain weight by strengthening their underdeveloped intestinal barrier.
An immature or “leaky” gut can lead to necrotizing enterocolitis (NEC), which is the third leading cause of death for newborns in the United States and worldwide. In fact, NEC affects up to 10 percent of premature babies with a devastating mortality rate of up to 50 percent.
Our discovery could lead to promising and practical clinical interventions to strengthen the gut of infants and thereby increase survival rates for the most vulnerable preterm infants.”
Dr. Bing Ma, PhD, Assistant Professor of Microbiology and Immunology at UMSOM
Bifidobacteria in the gut or microbiome have long been known to have health benefits. It includes a diverse set of strains that have very different properties. Some strains are only found in adults; some are mostly in their teens. One strain, Bifidobacterium infantis, has been observed predominantly in term infants.
The researchers followed 113 premature babies who were born between 24 and 32 weeks of gestation. This study found Bifidobacterium breve (B. breve) only in premature infants who had improved intestinal barrier function within a week after birth. Dr. Ma and her colleagues discovered that Bifidobacterium breve is genetically equipped to digest nutrients within the cell membrane rather than the more typical external digestion process in which bacteria secrete digestive enzymes onto nutrients to break them down.
At the most basic level, the gut microbiome in these preemies breastfed with more B. breve metabolizes carbohydrates differently than it does with formula. The researchers say they hypothesize that this metabolism process then strengthens and matures the intestinal barrier faster, protecting fragile newborns from disease.
“We now know that it is not just breast milk that helps premature babies develop their intestinal barrier faster,” said Dr. Ma. “We will need to find the best way to prophylactically administer B. breve early in life. life, rather than relying on transmission of breast milk or even the mother’s gut or vaginal microbiota during the birth process. This is especially critical in formula-fed preterm infants.”
Dr. Ma said more studies are needed to determine whether B. breve originated in breast milk, the intestine, the mother’s vagina, or even the environment.
E. Albert Reece, MD, PhD, MBA, Executive Vice President for Medical Affairs at the University of Maryland, Baltimore, John Z. and Akiko K. Bowers Distinguished Professor, and Dean of UMSOM, said, “This research may have a great impact”. achieving a global impact. Ultimately, it could save thousands of premature babies from permanent disability or death associated with an immature, leaky gut that allows deadly bacteria to enter.”
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Magazine Reference:
Mom, B. et al. (2022). Highly specialized carbohydrate metabolism capacity in bifidobacteria strains associated with gut barrier maturation in early preterm infants. mBio. doi.org/10.1128/mbio.01299-22.