Researchers found that childhood allergies, including eczema, hay fever, and food allergies, may develop because of imbalances in the gut biome during infancy.
The gut biome is a complex collection of microorganisms that live in the digestive tract. Moreover, the gut microbiome begins to develop in infancy and can be influenced by many factors. These include diet, environmental exposures, and antibiotic use.
Research suggests that gut microbiome disturbances may lead to neurodevelopmental disorders. For example, recent studies found altered gut biomes in children with attention deficit hyperactivity disorder (ADHD) and specific gut biome signatures in autistic individuals.
In addition, other reports indicate that changes in an infant's gut microbiome may lead to childhood allergies.
Now, a new study by researchers from the University of British Columbia and British Columbia Children's Hospital has found more evidence that microbiota in the digestive tract may influence whether a child develops allergies.
The study, published on August 29 in Nature Communications, identified a specific bacterial signature in the gut biome in children with food allergies, eczema, asthma, or hay fever.
The research is one of the first to examine microbiota signatures in all four allergic conditions simultaneously.
"These are technically different diagnoses, each with their own list of symptoms, so most researchers tend to study them individually. But when you look at what is going wrong at a cellular level, they actually have a lot in common," says co-senior lead author Charisse Petersen, a postdoctoral fellow at the University of British Columbia, in a news release.
To conduct the research, scientists examined the clinical data of 1,115 children from the Canadian CHILD Cohort Study (CHILD). The team used data from children tracked from birth to five years.
The data revealed that during the five-year study period, 592 children developed one or more allergies, and 523 children did not receive an allergy diagnosis.
To investigate differences in the children's gut microbiota, the researchers evaluated stool samples collected at clinical visits when the children were three months old and again at one year of age.
The stool sample analysis showed that children with allergies had a specific bacterial signature in their gut biomes. Specifically, the researchers found higher levels of bacterial species E. lenta, C. innocuum, E. faecalis, E. coli, and T. nexilis and lower amounts of A. hadrus, F. saccharivorans, E. hallii, and B. wexlerae.
Moreover, this bacterial signature is characteristic of an imbalanced gut biome — AKA gut dysbiosis — which can increase inflammation and damage the tissue that lines the intestines.
Co-senior author Stuart Turvey, a professor in the Department of Pediatrics at the University of British Columbia and a researcher at British Columbia Children's Hospital Research Institute, notes, "From these data, we can see that factors such as antibiotic usage in the first year of life are more likely to result in later allergic disorders while breastfeeding for the first six months is protective. This was universal to all the allergic disorders we studied."
The study authors say this discovery provides more insight into the associations between an infant's microbiome and allergy development. Though more research is needed, this new knowledge might eventually allow clinicians to predict whether a child is likely to develop allergies and lead to the creation of new prevention strategies.
- Nature Communications. Delayed gut microbiota maturation in the first year of life is a hallmark of pediatric allergic disease.
- The University of British Columbia. Researchers discover common origin behind major childhood allergies.