Scientists discovered that it is not just the composition of breastmilk that makes it better than formula milk. Based on the study published in the journal mBio, the ability of the bacteria present in breastmilk to absorb nutrients also makes a difference.
Breastmilk Bacteria Strengthens Infants' Gut
The study, led by Bing Ma, Ph.D., Assistant Professor of Microbiology and Immunology at UMSOM and an IGS researcher, discovered a strain of the bacteria Bifidobacterium breve, or B. breve, in the guts of breastfed babies who received more breastmilk than their counterparts. The bacteria helped them develop an intact intestinal wall one week after birth, so those preemies had better nutrient absorption.
The team discovered, for the first time, that the way B.breve metabolizes breastmilk helps breastfed babies to become healthy. The bacteria also helped the infants gain weight because their intestinal barriers were strengthened.
Bifidobacterium has long been known to be beneficial to the gut microbiome. It comprises a diverse set of strains with widely disparate properties. Some strains are only found in adults, whereas others are more common in adolescents. Bifidobacterium infantis is a strain found mostly in full-term infants.
The study followed 113 premature babies born between 24 and 32 weeks of gestation. B. breve was found only in preemies with improved gut barrier function within one week of birth. Dr. Ma and her colleagues discovered that B. breve is genetically capable of digesting nutrients within the cell membrane rather than the more common external digestion process in which bacteria secrete digestive enzymes onto nutrients to break them down.
At its most basic level, the gut microbiome of these breastfed preemies with more B. Breve handles carbohydrates differently than formula. According to the researchers, this metabolic process strengthens and matures the intestinal barrier faster, protecting vulnerable newborns from disease.
B. Breve Gut Bacteria in Leaky Gut
B. Breve was much less common in formula-fed and breastfed babies with leaky gut, a condition in which the gut does not develop a barrier to prevent bacteria and digested food from entering the bloodstream. Necrotizing enterocolitis (NEC), the third leading cause of newborn death in the United States and globally, can be caused by an immature or leaky gut. In fact, NEC affects up to 10% of premature babies, with a devastating mortality rate of up to 50%.
"Our discovery could lead to promising and practical clinical interventions to strengthen the babies' gut and, as a result, increase survival rates of the most vulnerable preemies," Dr. Ma said.
Researchers said that through the study, they now know that breastmilk alone does not accelerate the development of the intestinal barrier in preemies. Yet, they must figure out the best way to administer B. Breve as a preventative measure rather than relying on transmission through breastmilk or even the mother's gut or vaginal microbiota during birth. This is especially important for preemies who are fed formula.
This research has the potential to have a worldwide impact. It has the potential to save thousands of premature babies from permanent disability or death caused by an immature and permeable intestine that allows dangerous bacteria to enter.
Read also: Mooove Over: Breast Milk's Antimicrobial and Anti-inflammatory Effects are Superior to Cow's Milk
