Early Allergen Introduction

For decades, parents were told to delay introducing allergenic foods to babies. New landmark research has turned that advice on its head, showing that earlier introduction actually prevents allergies from developing.

If you are beginning your baby's weaning journey, you have probably heard conflicting advice about when to introduce foods like egg and peanut. The science is now clear: introducing common allergens early, around 6 months of age, is one of the most effective strategies to reduce your baby's risk of developing food allergies.

This guide breaks down the latest research, explains what it means for your family, and gives you a practical roadmap for introducing allergens safely.

The Science: What New Studies Show

Two major studies published in 2025 and 2026 have provided the strongest population-level evidence yet that early allergen introduction works at scale, not just in controlled trials.

The Egg Study (JAMA Pediatrics, June 2026)

A landmark study led by Professor Jennifer Koplin at the University of Queensland compared over 7,200 toddlers in Melbourne, Australia. The researchers looked at two groups: babies who had their one-year checkup between 2007 and 2011 (before guidelines changed), and those seen between 2018 and 2019 (after guidelines recommended early egg introduction).

The results were striking. After Australia updated its guidelines in 2016 to recommend introducing egg within the first year of life, the proportion of infants who had tried egg by 6 months more than doubled, rising from 25% to 57%. This shift in feeding behaviour was accompanied by a meaningful decline in egg allergy.

The Peanut Study (Pediatrics, October 2025)

A separate study led by researchers at the Children's Hospital of Philadelphia (CHOP) analysed medical records from dozens of paediatric practices across the United States. Using the American Academy of Pediatrics CER2 database, they compared food allergy diagnosis rates before and after the publication of early peanut introduction guidelines.

The study also revealed that peanut is no longer the most common food allergen in children; egg has now surpassed it. This shift likely reflects the success of targeted peanut introduction campaigns that began after the landmark LEAP trial in 2015.

How the Guidelines Changed

Understanding how expert recommendations evolved helps explain why you might have heard different advice from different sources over the years.

2000: The American Academy of Pediatrics advised delaying egg until age 2 and peanut until age 3 for high-risk infants. This was based on expert opinion, not clinical trials.

2008: The AAP reversed course, acknowledging there was "little evidence" that delaying allergenic foods prevented allergies.

2015: The LEAP trial showed that introducing peanut to high-risk infants between 4 and 11 months reduced peanut allergy risk by 81%. This was a turning point.

2016–2017: Australia, the US, and other nations updated guidelines to recommend early introduction of peanut and egg. The NIAID published addendum guidelines for peanut introduction.

2021–2026: Guidelines further liberalised to recommend early introduction of all major allergens for all infants (not just high-risk), starting around 4 to 6 months. The USDA 2025–2030 Dietary Guidelines now include this recommendation.

Key Allergens to Introduce Early

Current guidelines recommend introducing the following common allergenic foods around 6 months of age, once your baby has started solids and tolerated a few first foods like pureed vegetables or infant cereal. Introduce one new allergen at a time, and continue offering it regularly (at least twice per week) to maintain tolerance.

How to Introduce Allergens Safely

While early introduction is strongly supported by evidence, it is important to do it safely. Here is a step-by-step approach recommended by paediatric allergists.

What About High-Risk Babies?

Most babies can begin allergen introduction at home without any prior testing. However, some babies are considered higher risk and may benefit from additional guidance.

It is important to note that even for high-risk babies, the goal is still early introduction, not avoidance. Current guidelines from the National Institute of Allergy and Infectious Diseases (NIAID) recommend that high-risk infants be introduced to peanut as early as 4 to 6 months, ideally with medical guidance. Delaying introduction in these babies may actually increase their risk.

For all other babies, including those with mild eczema, a family history of allergies, or no risk factors at all, allergenic foods should be introduced in the first year of life without delay. No testing is needed beforehand.

Recognising an Allergic Reaction

While serious reactions to first-time food introductions are uncommon, it is important to know what to look for. Allergic reactions typically occur within minutes to two hours of eating the food.

Mild to moderate signs:

Hives or red welts on the skin, swelling of the lips or eyes, vomiting, or increased fussiness. If you notice these, stop offering the food and contact your doctor for advice.

Severe signs (call emergency services immediately):

Difficulty breathing, noisy breathing or wheezing, tongue or throat swelling, or your baby becoming pale and floppy. These signs require immediate medical attention.

SOURCES

1. Koplin JJ et al. "Population-level reduction in egg allergy after updated infant feeding guidelines." JAMA Pediatrics. Published online June 8, 2026.
2. Gabryszewski SJ et al. "Reduction in IgE-mediated food allergy diagnoses following early peanut introduction guidelines." Pediatrics. 2025;156(5).
3. Du Toit G et al. "Randomized trial of peanut consumption in infants at risk for peanut allergy (LEAP)." New England Journal of Medicine. 2015;372(9):803-813.
4. American Academy of Pediatrics. "When to Introduce Egg, Peanut Butter & Other Common Food Allergens." HealthyChildren.org. Updated June 2025.
5. National Institute of Allergy and Infectious Diseases. "Addendum Guidelines for the Prevention of Peanut Allergy." 2017.
6. ASCIA. "How to Introduce Solid Foods to Babies for Allergy Prevention." Australasian Society of Clinical Immunology and Allergy. 2024.
7. US Department of Agriculture. "Dietary Guidelines for Americans 2025–2030." Published January 2026.