MONDAY, May 8, 2017 (HealthDay News) -- Mothers have been told for years that breast-feeding is best. Now researchers say they've found a new way it helps babies -- by planting good bacteria in their digestive system.
For the study, the researchers assessed 107 breast-feeding mother-infant pairs. The investigators found that 30 percent of beneficial bacteria in a baby's intestinal tract comes directly from the mother's milk, and 10 percent comes from skin on the mother's breast.
"Breast milk is this amazing liquid that, through millions of years of evolution, has evolved to make babies healthy, particularly their immune systems," said senior study author Grace Aldrovandi. She is a professor of pediatrics and chief of infectious diseases at UCLA's Mattel Children's Hospital.
"Our research identifies a new mechanism that contributes to building stronger, healthier babies," she explained in a UCLA news release.
Also, babies who are breast-fed every day even after they begin eating solid food continue to benefit in the form of a growing population of beneficial bacteria linked with better health, Aldrovandi and colleagues said.
Previous research has shown that a balanced bacterial community in the intestines plays a major role in protecting against immune diseases.
For example, children who develop type 1 diabetes have abnormalities in their gut's bacterial populations. And healthy bacteria in the gut appears to provide lifelong protection against allergies, asthma and inflammatory bowel disease, the study authors noted.
"We're appreciating more and more how these bacterial communities -- particularly in the intestine -- help guard against the bad guys. 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," Aldrovandi said.
The study did not examine how children who are fed only formula acquire healthy bacteria in the gut.
Aldrovandi's team wants to do further research in this area, including how bacteria provided through breast-feeding play a crucial role in infants' immune responses, and which beneficial bacteria are missing in people who have certain diseases.
The findings were published May 8 in the Journal of the American Medical Association.
The American Academy of Pediatrics has more on breast-feeding.