New research sheds light on why food allergies develop in children

Food allergy is a growing health concern, currently affecting more than 33 million people in the U.S. alone. For years, parents and clinicians have faced conflicting advice on why these life-threatening allergies develop early in life and how to prevent them. I recently worked with colleagues around the world to perform a systematic review and meta-analysis, encompassing 2.8 million participants across 190 studies in 40 countries to provide an evidence-based map of the risk factors and an estimated global incidence of food allergy.

How common are food allergies?

Our study found that nearly 5% of children develop a confirmed food allergy by age 6. But where a child lives appears to matter. Rates were highest in Australia (10.2%) and the United States (6.7%), while much lower rates were seen in the Middle East (2.4%) and Africa (1.8%).

How to identify high-risk individuals in early life

We evaluated 342 potential risk factors, classifying them into “major” and “minor” categories based on the strength of their association. The strongest predictors for developing a food allergy included:

• Early antibiotic exposure: Infants given systemic antibiotics in their first month of life face a significantly higher risk (OR 4.11), highlighting the importance of early microbial colonization for a healthy immune system.
• The “atopic march”: Pre-existing allergic conditions were highlighted as risk factors. Atopic dermatitis (eczema) within the first year (OR 3.88), allergic rhinitis (OR 3.39) and early-life wheezing are major red flags.
• Skin barrier issues: Children with a weakened skin barrier, including those with eczema or certain genetic traits (e.g., specific filaggrin gene variations), may be at higher risk of developing food allergies because allergens can enter the body more easily through the skin.
• Demographics and social context: Self-identification as Black (OR 3.93) and parental migration prior to birth (OR 3.28) are major risk factors, reflecting how environmental and social contexts impact disease incidence.

One of the most actionable findings is that delayed solid food introduction — specifically waiting until after 12 months for peanuts (OR 2.55) or 6 months for fish — is a major modifiable risk factor. This reinforces the strategy of introducing allergenic solids early to help the infant’s immune system develop tolerance.

Surprisingly, several factors historically suspected of contributing to allergies showed no significant risk difference. These include maternal diet during pregnancy (e.g., intake of fish, cheese or specific nutrients), maternal stress, birth weight and breastfeeding.

What does the evidence tell us and what should we do about it

Our research suggests that food allergies arise from the convergence of biological, microbial and environmental influences and offers a roadmap for prevention-focused policy. By clarifying these risk factors, clinicians can more accurately define “high-risk” populations and intervene early. Effective prevention must focus on targeting modifiable factors: maintaining skin barrier health, using antibiotics judiciously and prioritizing the early introduction of allergenic foods.

By Dr. Aikaterini Anagnostou, professor of pediatrics, Division of Immunology, Allergy and Retrovirology, Texas Children’s Hospital & Baylor College of Medicine