Food Allergies Are Influenced by More Than Genetics

A JAMA Pediatrics review pooling 190 studies with 2.8 million participants found genetics do not fully explain childhood food allergies and identified factors such as antibiotic exposure and delayed introduction of allergenic foods as linked to higher risk.

Researchers report that genetics alone cannot fully explain which children develop food allergies. The review, published Feb. 9 in JAMA Pediatrics, pooled data from 190 studies including about 2.8 million participants across 40 countries. Investigators examined more than 340 potential factors that might influence allergy risk. Senior researcher Dr. Derek Chu of McMaster University described interactions among genes, skin health, the microbiome and environmental exposures as relevant. Key findings: - The pooled data suggested about 5% of children develop a food allergy by age 6. - Certain early-life factors were associated with higher risk, including antibiotic use during pregnancy or a baby's first year, other immune system diseases, and delayed introduction of allergenic foods; antibiotic exposure was linked to a 32%–39% increase in risk. - Several suspected factors showed no clear link in the review, including low birth weight, post-term birth, lack of breastfeeding, and a mother's diet and stress during pregnancy. - The research team examined over 340 distinct factors across the included studies. Summary: The review indicates that environmental and early-life influences add to genetic risk in childhood food allergies and provides a broader view of factors linked to onset. The authors called for future studies that measure the same key factors, include more diverse populations, use food challenge testing more often, and for new randomized trials and updated guidelines to help translate these findings into practice.