Gut health: Breastfeeding found to ‘profoundly influence’ development of infant microbiome

That breastfeeding provides baby with the perfectly tailored nutrients and strengthens their immune system is widely known.

But researchers have also started discovering just how important human milk is in shaping infants' gut health and microbiome – and area of medicine and health that have gained a massive amount of attention and importance in the last couple of years. According to a study published in JAMA Pediatrics, bacteria found in mother's milk and areolar skin seed the infant gut and profoundly influence the development of infant microbiome. Grace M. Aldrovandi, MD, professor of paediatrics, chief of the Division of Pediatric Infectious Diseases at the David Geffen School of Medicine at the University of California, Los Angeles, explains:

"We sought to determine the role of breast milk and breastfeeding in establishing infant gut microbial communities and found that breast milk contributes 27.7% and breastfeeding an additional 10.4% (from the areolar skin) of the bacteria to the infant gut in the first 30 days [of life]."

The 12-month-long longitudinal study saw researchers enrolling 107 healthy mother-infant pairs from California and Florida, between 2010, and 2015. The mother-infant pairs were divided into 5 groups on the basis of infant age: 0 to 7 days, 8 to 30 days, 31 to 90 days, 91 to 180 days, and 181 to 365 days. At the time of sample collection, median infant age was 40 days (range, 1-331 days); 85.1% of infants were primarily breast-fed (breast milk made up >75% of their daily milk intake). Bacterial composition of breast milk, areolar skin, and infant stool samples was assessed by sequencing of the 16S ribosomal RNA gene.

Profound differences in the composition and diversity of bacterial communities present in milk, areolar skin, and infant stool were discovered, with Pterobacteria were predominantly found in milk, Firmicutes in areolar skin, and Actinobacteria dominated in infant stool. The infants who were primarily breast-fed derived 38.1% of bacteria from breast milk (27.7%) and areolar skin (10.4%), and bacterial colonization from these 2 sources was the most pronounced during the first month of infant's life. And the benefits lasted a long time, with the effect of breastfeeding on gut microbiome composition notable even after the introduction of solid foods in infants aged 4 to 6 months.

"We found that continued breastfeeding after solid food introduction suppressed the diversification and enrichment of bacteria typically associated with solid foods," explained Dr Aldrovandi.

Protects against obestiy Interestingly, the study also established a connection between continued breastfeeding and bacteria associated with childhood obesity and asthma. "We showed that continued breastfeeding after the introduction of solid foods appears to be important to suppress some bacteria associated with obesity," emphasized Dr Aldrovandi, who added, "Our findings and others show that breast-feeding increases bacteria that have been associated with a lower incidence of asthma." The researchers are keen topoint out that these findings strike an important note in the light of increasing concerns about the incidence rates of childhood asthma (8.4%) and obesity (17%) in American children. "This work supports and strengthens the evidence for the current guidelines from both the World Health Organization and the American Academy of Pediatrics for exclusive breast-feeding for the first 6 months of life with continued breast-feeding for at least 12 months," concluded Dr Aldrovandi.