THURSDAY, Sept. 19, 2024 (HealthDay News) -- Breastfeeding through the first year of infants' lives can lower their risk of asthma by colonizing their bodies with a healthy mix of microbes, a new study finds.

Results show that breastfeeding beyond three months supported the gradual maturation of a baby’s gut microbiome, researchers reported Sept. 19 in the journal Cell.

On the other hand, stopping breastfeeding earlier than three months disrupts development of the microbiome and is linked to a higher risk of preschool asthma, researchers said.

Breast milk contains complex sugars and other nutrients that boost the growth of healthy microbes in their gut, they explained.

On the other hand, baby formula contains nutrients that promote growth of a different set of microbes. While many microbes that thrive on formula eventually develop in all babies, their early arrival is linked to an increased risk of asthma, researchers report.

“Just as a pacemaker regulates the rhythm of the heart, breastfeeding and human milk set the pace and sequence for microbial colonization in the infant’s gut and nasal cavity, ensuring that this process occurs in an orderly and timely manner,” said co-senior investigator Liat Shenhav, a computational biologist and assistant professor at NYU Grossman School of Medicine in New York City.

“Healthy microbiome development is not only about having the right microbes. They also need to arrive in the right order at the right time,” Shenhav added in an NYU news release.

For the study, researchers tracked the ebb and flow of microbes in the gut and noses of infants during their first year of life, drawn from a long-term health research project involving 3,500 Canadian children.

Researchers found that a bacterial species called Ruminococcus gnavus appears much sooner in the guts of children weaned early from breast milk.

This bacteria is known to be involved in the formation and breakdown of tryptophan, an amino acid that’s been linked to immune system problems like asthma.

As a result, an infant’s microbiome actually plays a crucial role in the development of their immune system, researchers said.

Breastfeeding duration played a powerful role in an infant’s microbiome even after other factors were taken into account, such as exposure to smoke or antibiotics, researchers said.

Based on their findings, researchers created a computer model that showed the primary way breastfeeding reduces asthma risk is by shaping a baby’s microbiome.

“Our research highlights the profound impact of breastfeeding on the infant microbiome and breastfeeding’s essential role in supporting respiratory health,” Shenhav said. “By uncovering the mechanisms behind the protective effects of breast milk, as demonstrated in this study, we aim to inform national guidelines on breastfeeding and weaning from breast milk in a data-driven manner.”

“With further research, our findings could also contribute to developing strategies to prevent asthma in children who cannot be breastfed for at least three months,” Shenhav added.

More information

The U.S. Centers for Disease Control and Prevention has more about the benefits of breastfeeding.

SOURCE: NYU Langone Health, news release, Sept. 19, 2024