Can you do something to prevent allergies in your baby? Yes, actually you can. Research has turned the old recommendations upside down: early introduction of allergens is now the most important thing you can do.

This guide gives you a complete overview of allergy prevention based on current WHO and AAP guidelines, landmark international research (PreventADALL, LEAP, EAT), and practical tips for safe introduction.

Important: This article is about preventing allergies in healthy babies. If your baby has already shown allergic reactions, talk to your doctor. If your baby has severe atopic eczema, allergen introduction should be discussed with a physician.

New Recommendations: Early Introduction Prevents Allergy

Earlier, parents were advised to delay allergenic foods. That era is over.

The WHO and major pediatric organizations including the AAP now recommend that all infants — including those with a family history of allergy — should be introduced to allergenic foods during their first year of life. Taste portions can be offered from 4–6 months of age.

The research is clear: babies who receive allergenic foods early develop food allergies far less often than babies who wait.

What Does This Mean in Practice?

Don't delay egg, peanuts, tree nuts, fish, and other allergens
Introduce them as a natural part of food introduction from 4–6 months
One new allergen at a time, with 2–3 days in between
Continue giving the allergen regularly after introduction (this is important for the effect)

What Does the Research Show?

The PreventADALL Study

The PreventADALL study was led by Oslo University Hospital and is one of the world's largest studies on allergy prevention. Over 2,300 Norwegian and Swedish mother-infant pairs participated.

Results published in The Lancet in 2022 showed that babies who received taste portions of peanut, egg, cow's milk, and wheat from 3–4 months of age had around 60% lower risk of food allergy by age three.

Only 1.1% in the intervention group developed allergy
2.6% in the control group developed allergy
Effect was strongest for peanut and egg

Researchers estimated that if all babies received early allergen taste portions, around 1,000 children per year in Norway alone would avoid food allergy — a significant preventive effect.

The LEAP Study

The international LEAP study (2015) showed that children who received peanut products early had an 81% lower risk of peanut allergy. This study triggered a worldwide change in guidelines.

The EAT Study

The EAT study from the UK confirmed that early introduction of six allergens (peanut, egg, milk, wheat, fish, sesame) from 3 months of age was safe and reduced allergy rates.

Research vs. guidelines: These studies led to updated international recommendations. Current AAP and WHO guidance supports starting solid foods around 6 months (or 4–6 months when developmentally ready), and introducing allergens as part of that food introduction process.

The 9 Most Common Allergens

Here are the most common allergens you should introduce, with age guidance and practical tips:

1. Egg

From age: 4–6 months
How: Well-cooked egg (scrambled, hard-boiled egg mashed into porridge)
Start with: Half a teaspoon of cooked egg yolk, then whole cooked egg
Tips: Never raw egg for babies

2. Peanuts

From age: 4–6 months
How: Peanut butter (thin layer) mixed into porridge or on bread
Never: Whole peanuts (choking hazard for children under 4 years)
Tips: Mix half a teaspoon of smooth peanut butter into a little breast milk/water for a thin paste

3. Cow's Milk / Dairy Products

From age: 10 months for cheese, yogurt, milk in cooking
Cow's milk as drink: From 12 months
Start with: Plain yogurt (max 1/4 cup/day from 10 months), cheese on bread
Tips: Small amounts of cow's milk in cooking can be introduced earlier

4. Wheat / Gluten

From age: 4–6 months (via porridge/cereal)
How: Iron-fortified infant cereal, soft bread, pasta
Tips: Early gluten introduction is recommended by AAP and WHO

5. Fish

From age: 6 months
How: Cooked and mashed white fish (cod, tilapia), then salmon
Tips: Start with mild fish types, well-cooked and well-mashed

Parent introducing allergenic foods to baby in a safe kitchen environment

6. Tree Nuts

From age: 6 months
How: Nut butter or finely ground nuts mixed into porridge/food
Never: Whole nuts (choking hazard for children under 4 years)
Types: Hazelnut, cashew, walnut, almond

7. Sesame

From age: 6 months
How: Tahini (sesame butter) mixed into food, hummus
Tips: Sesame is a common allergen trigger that many families overlook

8. Soy

From age: 6 months
How: In small amounts via soy-based foods (tofu, edamame)
Tips: Found in many processed products

9. Shellfish

From age: 6 months
How: Cooked and mashed (shrimp, crab)
Tips: Start with shrimp — a common shellfish allergy trigger

How to Introduce Allergens Safely

Follow these steps for safe introduction:

Step 1: Start Small

Give a small taste portion — about half a teaspoon. For example: peanut butter mixed into a little porridge.

Step 2: Give Early in the Day

Introduce new allergens early in the day so you can observe your baby for several hours afterward.

Step 3: Wait 2–3 Days

Introduce only one new allergen at a time. Wait 2–3 days before the next one, so you can link any reactions to the right food.

Step 4: Observe Your Baby

Watch for signs of an allergic reaction in the 1–2 hours after eating:

Rash around the mouth or on the body
Swelling of the lips or face
Vomiting or diarrhea
Agitation, crying, itching

Step 5: Continue Regularly

After successful introduction: give the allergen regularly (2–3 times per week). Research shows that regular exposure is important for the protective effect to last.

Call emergency services if your baby shows signs of a severe allergic reaction (anaphylaxis): difficulty breathing, swelling of the throat or tongue, pallor, limpness, or sudden deterioration. Severe reactions are rare, but it's important to know the signs.

Risk Factors for Allergy

Some babies have a higher risk of developing food allergy:

Atopic Eczema

Babies with moderate to severe atopic eczema have an elevated risk of food allergy. For these babies, early allergen introduction is especially important — but should be done with guidance from a doctor.

Family History

Children with parents or siblings who have allergies (food allergy, asthma, hay fever, eczema) have slightly higher risk. But early introduction is equally important (if not more so) for these babies.

Already Identified Allergy

If your baby has already reacted to an allergen, don't introduce new allergens without speaking to your doctor first.

Even for babies with elevated risk, AAP and WHO recommend early allergen introduction. It is no longer recommended to delay allergens for high-risk babies. Speak to your pediatrician if your baby has severe eczema.

Breastfeeding and Allergy Prevention

What is breastfeeding's role in allergy prevention?

WHO recommends breastfeeding through the entire first year and beyond
Breast milk contains immunoglobulins that support the baby's immune system
Breastfeeding alone doesn't necessarily prevent food allergy, but is beneficial for the baby's overall health
Allergens the mother eats pass into breast milk in very small amounts — this can actually contribute to tolerance development
It is not necessary to avoid allergens while breastfeeding unless the baby has a confirmed allergy

Myths About Allergy Prevention

Myth 1: "Wait until the child is older before giving allergens"

Wrong. Current research and international guidelines say the opposite: early introduction (from 4–6 months) prevents allergy. Waiting actually increases the risk.

Myth 2: "Avoid peanuts during pregnancy"

Wrong. It is not necessary to avoid allergens during pregnancy. There is no evidence that the mother's diet during pregnancy increases the baby's allergy risk.

Myth 3: "Allergy can only be prevented with special supplements"

Wrong. The most important preventive measure is simple and inexpensive: give your baby allergenic foods early and regularly. No special supplements are needed for allergy prevention.

Myth 4: "If there's allergy in the family, the baby should avoid allergens"

Wrong. Early introduction is equally important (perhaps more so) for babies with a family history of allergy. Talk to your pediatrician if your baby has severe eczema.

Frequently Asked Questions

How early can I introduce peanuts to my baby?

Peanut butter can be introduced from 4–6 months of age as part of food introduction. Mix half a teaspoon of smooth peanut butter into porridge or breast milk. Never give whole peanuts (choking hazard). LEAP study and AAP guidelines support early introduction.

Should I get allergy testing before introducing allergens?

No. Routine allergy testing for babies is not recommended by the AAP or WHO. All babies should receive allergenic foods as part of normal food introduction. Exception: babies with severe atopic eczema should discuss the plan with their pediatrician first.

My baby has eczema — is it safe to give allergens?

Mild eczema is not a reason to delay allergen introduction. For babies with moderate to severe atopic eczema, speaking with a pediatrician about an allergen introduction plan is recommended. Early introduction is especially important for these babies, but should be supervised.

Can the baby become allergic from early introduction?

No — the research shows the opposite. Early introduction reduces the risk of allergy. It's important to start with small amounts and observe your baby, but the introduction itself doesn't increase the risk.

How often should the baby eat allergens after introduction?

Give each allergen 2–3 times per week after successful introduction. Regular exposure is important to maintain tolerance. Ensure variety — rotate different allergens throughout the week.

What do I do if the baby reacts?

For a mild reaction (slight rash around the mouth): wait and observe. Try the allergen again after a few days in a small amount. For a stronger reaction (widespread rash, vomiting, swelling): stop giving the food and contact your pediatrician. For difficulty breathing or anaphylaxis: call emergency services immediately.

Family with baby at the dinner table with a variety of foods

Summary

Early introduction of allergens (from 4–6 months) is the most important thing you can do to prevent allergy in your baby. International guidelines from the AAP and WHO, and landmark research from the PreventADALL and LEAP studies, recommend that all babies — including those with a family history — receive allergenic foods early. Start with egg and peanut butter, introduce one allergen at a time, and continue regularly.

Sources

American Academy of Pediatrics (AAP). "Preventing Food Allergy in Children." aap.org
WHO. "Infant and young child feeding." who.int
Skjerven et al. "Early food intervention and skin emollients to prevent food allergy in young children." The Lancet, 2022. (PreventADALL study)
Du Toit et al. "Randomized trial of peanut consumption in infants at risk for peanut allergy." New England Journal of Medicine, 2015. (LEAP study)
Perkin et al. "Randomized Trial of Introduction of Allergenic Foods in Breast-Fed Infants." New England Journal of Medicine, 2016. (EAT study)

Last updated: March 2026