The guidance on introducing allergenic foods to babies has changed significantly in the past decade, and many parents are working with outdated advice — or no advice at all — about when and how to introduce the foods that carry the highest allergy risk. The shift is substantial: where parents were once told to delay allergens, the evidence now points in precisely the opposite direction.
Understanding the current guidance, who it applies to, how to introduce allergens practically, and what to watch for helps parents navigate this aspect of weaning with confidence rather than anxiety.
Healthbooq is useful during the introduction of allergens for logging which foods you have introduced, on what date, and any reactions you observed — creating a clear record of your baby's weaning history that is genuinely useful at health visits.
The Evidence on Early Introduction
Several large randomised controlled trials — most notably the LEAP trial (Learning Early About Peanut allergy) — have demonstrated that introducing allergenic foods in the weaning period substantially reduces the rate of allergy development compared to delaying them. The LEAP trial found that regular peanut consumption from the weaning period reduced peanut allergy in high-risk babies by approximately 80% compared to avoidance. Similar findings have been replicated for other allergens.
The mechanism is immunological: the immune system is more likely to develop tolerance to a food that it encounters early and repeatedly than to develop a sensitised allergic response. Delaying allergen introduction, which was the advice given for decades, may have contributed to the rise in food allergy rates that has been observed in the past thirty years.
Current Guidance for Most Babies
For babies without significant eczema and without a known existing food allergy, the current guidance is to introduce allergens from around six months alongside other weaning foods. The major allergens to introduce are: cow's milk products (such as yoghurt or cheese — whole cow's milk is not introduced as a main drink before twelve months), cooked egg (well-cooked, not runny), peanut products (smooth peanut butter mixed into food — whole peanuts and whole nuts are choking hazards and not given before five years), wheat, tree nuts, fish, and soy.
Introduce one new allergen at a time, and wait two to three days before introducing another, so that if a reaction occurs you can identify the cause clearly. Choose a time when your baby is well — not teething particularly badly, not showing signs of illness — and a time of day when you will be able to observe the baby for a period of an hour or two afterward. Morning or lunchtime introduction means that if there is a reaction, you have access to medical care during the day.
Recognising an Allergic Reaction
Mild allergic reactions to new foods — redness or hives around the mouth or face, mild swelling of the lips, watery eyes — are the most common form of reaction and are generally manageable. They typically resolve within one to two hours. Antihistamine (appropriate dose for the baby's age) can be given for mild skin reactions; your health visitor or GP can advise on which antihistamine is appropriate.
Anaphylaxis — severe allergic reaction involving the airway, difficulty breathing, widespread hives, vomiting, and signs of cardiovascular compromise — is very rare during food introduction in babies and requires emergency medical care (call 999). Having an action plan is sensible if your baby is in a high-risk category, but anaphylaxis during initial food introduction is not the routine experience.
High-Risk Babies
Babies with moderate to severe eczema (established before four months, not controlled with standard emollient) or with a known existing food allergy are at higher risk of food allergy development. For these babies, consultation with an allergy specialist or paediatric allergist before introducing high-risk allergens — particularly peanuts and egg — is recommended. For babies with mild eczema, home introduction on the same timeline as other babies is generally appropriate.
In the UK, the BSACI (British Society for Allergy and Clinical Immunology) provides a specific accelerated introduction protocol for high-risk babies, often referred to as the "BeEAT" approach. This is designed to be used under healthcare guidance rather than independently.
Key Takeaways
Current guidance strongly recommends introducing the major allergens — including peanuts, egg, dairy, wheat, and fish — during the weaning period (from around six months) rather than delaying them. Early introduction is associated with lower rates of allergy development, and delayed introduction does not protect against allergy. For babies with mild-to-moderate eczema or an existing known food allergy, an accelerated introduction programme under healthcare guidance may be appropriate. Allergic reactions during introduction are generally mild and manageable at home; anaphylaxis during initial food introduction is very rare.
