A new study led by McMaster University, involving 2.8 million children globally, has identified the most significant early-life factors influencing the development of food allergies in children. The research, published in JAMA Pediatrics on February 9, 2026, sheds new light on this growing health concern.
The study suggests that food allergies result from a combination of genetic, environmental, microbial, and social factors rather than a single cause. Approximately five percent of children develop a food allergy by age six.
Study Methodology
Researchers undertook a rigorous systematic review and meta-analysis of 190 studies focused on childhood food allergy. This comprehensive approach included studies that utilized gold-standard food challenge testing to confirm allergies, allowing for the examination of over 340 different potential influencing factors.
Key Risk Factors Identified
The research pinpointed several early-life factors that significantly increase the risk of developing food allergies:
- Eczema and Other Allergies: Infants who experience eczema in their first year are three to four times more likely to develop a food allergy. The study also found that wheezing or nasal allergies elevate this risk.
- Family History: Children with allergic parents or siblings have a higher likelihood of developing a food allergy, particularly when both parents have allergies.
- Delayed Introduction of Allergenic Foods: Waiting too long to introduce common allergenic foods like peanuts, nuts, and eggs can notably increase the chance of developing an allergy. Babies introduced to peanuts after 12 months were more than twice as likely to become allergic to them.
- Antibiotic Use: Antibiotic use during the first month of life was linked to a higher risk of food allergy. Use later in infancy or during pregnancy was also associated with increased risk, though to a lesser extent.
"Infants who experience eczema in their first year are three to four times more likely to develop a food allergy."
Factors Not Associated with Increased Risk
The study also provided clarity on factors that were not linked to a higher risk of food allergies. These included low birthweight, post-term birth, partial breastfeeding, maternal diet, and maternal stress during pregnancy.
Implications and Future Research
The findings are poised to help identify infants at highest risk who could benefit from early prevention strategies. Senior author Derek Chu emphasized the need for future studies to measure and adjust for key factors, include more diverse populations, and frequently use food challenge testing.
"New randomized clinical trials and updated guidelines are also urgently required to translate these findings into practical action."