Newborn’s gut microbes affect allergies later

The gut bacteria of a newborn baby can signal whether the child will develop allergies and asthma later in life, a new study suggests.

The research comes from a 13-year investigation into factors that may contribute to the onset of asthma, a project conducted by a team from the University of California, San Francisco and the Henry Ford Health System in Detroit, US.

According to previous studies, the likelihood of a child developing asthma can depend on factors from breastfeeding and vaginal birth to having dogs in the home during a baby’s first months of life.

“We have been working for over a decade, trying to figure out why some children get asthma and allergies and some don’t,” says co-senior author Christine Cole Johnson, chair of public health sciences in the Henry Ford Health System.

“It seems that the microbial communities within the body could be the keystone to understanding this and a number of different immune diseases.”

Since 2003, the team monitored hundreds of infants from diverse backgrounds through birth and early childhood development.

Stool samples were gathered from infants aged between one and 11 months and were kept on ice. These samples were re-examined using new technology to analyse the bacterial and fungal makeup of each infant’s gut.

Among the test subjects, a small group of infants was found to be three times more likely to develop asthma than others. This group represented 11 of 130 infants, a statistic that is strikingly similar to the approximate percentage of asthma patients among the general public.

According to the study’s findings, published in Nature Medicine, that small group of infants had something else in common: they were missing a few crucial gut bacteria but high levels of fungal species.

The group was also missing a wide range of molecules thought to be associated with reducing inflammation and nourishing T-regulatory cells, which are crucial for maintaining a healthy immune system.

“Asthma has doubled in prevalence in modern ‘westernised’ societies about every 20 years for the past 60 or 70 years, so an effective strategy for prevention is becoming an urgent need for public health,” explains Homer Boushey, also at the University of California, San Francisco and a study co-author.

“By focusing on the differences in microbial functions [between healthy and asthma-prone infants] — in their metabolic products and their effects on immune function — this kind of study helps define the pathway we’ll need to follow to prevent this disease.”

This finding suggests that early intervention into gut microbiota is key in avoiding the onset of asthma and allergies.

“If we are to prevent disease development, we need to intervene early,” says study co-author Susan Lynch. “Currently, children are typically six or seven years old when they are diagnosed with asthma, which has no cure and has to be managed through medication.

“But if the genesis of the disease is visible as a disruption of gut microbiota in the very earliest stages of postnatal life, it raises an exciting question: could we reengineer the community of microbes in at-risk infants to prevent allergic asthma from developing?”