Breast milk provides infants with the ideal nutrition. It also contains antibodies that help babies fight off viruses and harmful bacteria. New research also shows that nature’s marvelous elixir delivers good bacteria to an infant’s digestive system, providing a healthier immune system.
Researchers discovered that 27.7% of beneficial bacteria in a baby's intestinal tract come directly from the mother's milk, and 10.3% comes from the mother’s nipple. They also found that babies who breastfeed even after they begin eating solid food continue reaping the benefits of a breast milk diet — a growing population of beneficial bacteria associated with better health.
The mother’s positive bacterium assists the baby’s intestine to digest food and trains the infant’s immune system to recognize bacterial allies and enemies.
“Breast milk is this amazing liquid that, through millions of years of evolution, has evolved to make babies healthy, particularly their immune systems,” said Dr. Grace Aldrovandi, the study’s senior author and a professor of pediatrics and chief of infectious diseases at UCLA Mattel Children’s Hospital. “Our research identifies a new mechanism that contributes to building stronger, healthier babies.”
The study, which looked at 107 mother-infant pairs, is the largest to date showing the transfer of bacteria in the milk into the baby’s gut, Aldrovandi said.
Earlier research has shown that a balanced bacterial community in the intestine is a key factor in people’s susceptibility to immune diseases. For example, children who develop type 1 diabetes have abnormalities in their gut microbiomes; what’s more, a healthy gut appears to protect against allergies, asthma and inflammatory bowel disease throughout life.
“We’re appreciating more and more how these bacterial communities, particularly in the intestine, help guard against the bad guys,” Aldrovandi said. “We know from animal model systems that if you get good bacteria in your gut early in life, you’re more likely to be healthy.”
During the babies’ first year of life, researchers collected samples of breast milk and infant stool, and swabs from the skin around the nipple. They analyzed the samples to assess which bacteria were shared between mothers and infants, and calculated the relative abundance of the bacteria.
The research team wants to want to expand the research to evaluate more samples in late infancy to better understand the transition to an adult microbiome. They would like to test in the lab how bacteria that are provided through breastfeeding are critical in infants’ immune responses, and determine which beneficial bacteria are missing in people who have certain diseases.
The findings were published online in JAMA Pediatrics.