Breastfeeding is crucial for shaping babies’ microbes and promoting lung health, study shows

Human breast milk regulates a baby’s mix of microbes or microbiome during the child’s first year of life. This in turn lowers the child’s risk of developing asthma, a new study shows published in the news Cell shows.

Led by researchers from NYU Langone Health and the University of Manitoba, the study results showed that breastfeeding for more than three months supports the gradual maturation of the microbiome in the child’s digestive system and nasal cavity, the upper respiratory tract. Conversely, stopping breastfeeding earlier than three months disrupts the rapid development of the microbiome and has been associated with a higher risk of asthma in preschool age.

Some components in breast milk, such as complex sugars called breast milk oligosaccharides, can only be broken down with the help of certain microbes. This provides a competitive advantage for microbes that can digest these sugars.

Babies who stop receiving breast milk before three months and then rely exclusively on formula will end up with a different set of microbes: microbes that help the child digest the components in the formula. Although many of these microbes that thrive on formula eventually make their way to all babies, researchers have shown that their early arrival is linked to an increased risk of asthma.

“Just as a pacemaker regulates the rhythm of the heart, breastfeeding and breast milk set the pace and sequence for microbial colonization in the infant’s intestinal and nasal passages, ensuring that this process occurs in an orderly and timely manner,” said co-senior researcher. researcher and computational biologist Liat Shenhav, Ph.D.

“Developing a healthy microbiome isn’t just about having the right microbes. They also need to arrive at the right time in the right order,” said Shenhav, assistant professor at NYU Grossman School of Medicine, the Institute for Systems Genetics and the school’s Institute for Systems Genetics. Department of Microbiology.

For the study, Shenhav, who is also an assistant professor at NYU’s Courant Institute of Mathematical Sciences, collaborated with co-senior investigator Meghan Azad, Ph.D., director of the Manitoba Interdisciplinary Lactation Center, and a professor of pediatrics. and child health, at the University of Manitoba.

Another important research finding was that the bacteria species Ruminococcus gnavus appeared much earlier in the intestines of children who were deprived of breast milk early on than in children who were exclusively breastfed. The bacterium is known to be involved in the production of molecules called short-chain fatty acids, and in the formation and breakdown of the amino acid tryptophan.

Both tryptophan and its metabolites have been linked in previous research to the regulation and disruption of the immune system, including an increased risk of asthma. The study authors noted that a child’s microbiome not only helps with digestion, but also plays a crucial role in the development of the immune system.

The study tracked the ebb and flow of microbes in infants’ guts and noses during the first year of life, as well as details breastfeeding and the composition of breast milk. All children and their mothers participated in the CHILD Cohort Study, a long-term research project that studied the same 3,500 Canadian children at different stages of life from the womb through adolescence.

The data from the CHILD Cohort Study allowed researchers to disentangle the impact of breastfeeding on a baby’s microbiome from a range of other environmental factors, including exposure to prenatal smoke, antibiotics and the mother’s asthma history.

Even when these factors were taken into account, they found that the duration of breastfeeding remained a powerful determinant of the infant’s microbial composition over time. They also used these microbial dynamics and milk solids data to train a machine learning model that accurately predicted asthma years in advance.

Finally, they created a statistical model to learn causal relationships, which showed that the main way breastfeeding reduces asthma risk is by shaping the child’s microbiome.

“The algorithms we developed provide valuable insights into the microbial dynamics during an infant’s first year of life and how these microbes interacted with the child,” says Shenhav. “These insights have allowed us to go beyond identifying associations, improving our ability to make predictions and explore causal relationships.

“Our research highlights the profound impact of breastfeeding on infants’ microbiomes and the essential role of breastfeeding in supporting respiratory health. 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 may also contribute to the development of strategies to prevent asthma in children who cannot be breastfed for at least three months,” she added.