A new study from McMaster University, one of the largest to examine food allergies, furthers our understanding of how allergies develop—concluding that a combination of genetic, environmental, microbial and social factors influence allergies, rather than a single cause.
The study, involving 2.8 million children around the world, systematically examined over 340 different factors that may influence allergy. Some of the identified early-life factors that raised the risk of food allergies included:
- Infants who experience eczema in the first year of life are three to four times more likely to develop a food allergy—wheezing or nasal allergies also increases risk.
- Children with allergic parents or siblings were more likely to develop a food allergy, especially when both parents had allergies.
- Waiting too long to introduce allergenic foods such as peanut, nuts, eggs, or other common allergens can increase the chance of developing a food allergy. Researchers found babies who try peanuts after 12 months are more than twice as likely to become allergic to the legume.
- Another significant factor involves the use of antibiotics. The study highlights how antibiotic use in the first month of life can lead to a higher risk of food allergy. Antibiotics taken later in infancy and during pregnancy can lead to an increased risk, but to a lesser degree.
“Our study highlights that genetics alone cannot fully explain food allergy trends, pointing to interactions—or a ‘perfect storm’—between genes, skin health, the microbiome, and environmental exposures,” said Derek Chu, senior author of the study and assistant professor at McMaster University.
The findings help identify which infants are most at risk and could benefit most from early prevention strategies.
The study is published in JAMA Pediatrics.
Data from McMaster University