Millions of people worldwide are affected by allergies. And, like so many health conditions recently, they've been linked to gut health and the gut microbiome. Given that the microbiome and an infant's immune system mature in parallel, a new study has investigated the connection between the two.

Researchers from the University of British Columbia and the BC Children's Hospital, Canada, looked at the role that gut bacteria and early-life influences played in developing four major childhood allergies: eczema, asthma, food allergy and hay fever.

"We're seeing more and more children and families seeking help at the emergency department due to allergies," said Stuart Turvey, corresponding author of the study. "Hundreds of millions of children worldwide suffer from allergies, including one in three children in Canada, and it's important to understand why this is happening and how it can be prevented."

Although the four allergy types have their own symptoms, the researchers wanted to see whether they had a common origin that was linked to the composition of bacteria in the gut.

"These are technically different diagnoses, each with their own list of symptoms, so most researchers tend to study them individually," said Charisse Petersen, one of the study's co-authors. "But when you look at what is going wrong at a cellular level, they actually have a lot in common."