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A Dietitian’s Guide to Introducing Allergens

As a paediatric dietitian, one of the most common concerns I hear from parents is about introducing allergens when starting solids. The fear of an allergic reaction can make this exciting milestone feel overwhelming. However, current research shows that early introduction of allergens may actually help prevent food allergies, rather than cause them.

This article will walk you through when and how to introduce common allergens safely, based on the latest evidence and expert recommendations.

Why Early Allergen Introduction Matters

In the past, parents were often advised to delay giving their babies foods like peanuts, eggs, or fish. However, large studies such as the LEAP (Learning Early About Peanut Allergy) and EAT (Enquiring About Tolerance) trials have shown that introducing allergens in infancy, around the time solids are first introduced, can reduce the risk of developing allergies, especially in high-risk infants.

When to Introduce Allergens

You can start introducing allergens once your baby is developmentally ready for solids, usually around 6 months of age. Signs your baby may be ready include:

  • Good head and neck control
  • Sitting with minimal support
  • Interest in food
  • Reaching, grabbing, and bringing food to their mouths

Introduce allergens after your baby has tolerated a few non-allergenic foods.

What Are the Common Food Allergens?

The most common food allergens in infants include:

  • Peanut
  • Egg
  • Cow’s milk (dairy)
  • Wheat
  • Soy
  • Tree nuts (e.g. cashew, almond)
  • Fish
  • Shellfish
  • Sesame

How to Introduce Allergens Safely

  1. Choose a time when your baby is well and you can observe them for a few hours afterward (e.g., not just before bedtime).
  2. Start with a small amount, such as a quarter teaspoon of smooth peanut butter mixed into warm water or baby cereal.
  3. Continue offering the allergen regularly (2–3 times per week) once tolerated. This ongoing exposure is important to maintain tolerance.
  4. Do not introduce allergens for the first time at childcare or outside the home, where monitoring is harder.

Signs of an Allergic Reaction

Most reactions occur within minutes to 2 hours of eating. Watch for:

  • Hives or rash
  • Swelling of the lips, face, or eyes
  • Vomiting


If you notice any of these symptoms, seek medical attention immediately:

  • Coughing, wheezing, or breathing difficulty
  • Swelling of the tongue or throat
  • Pale skin or floppy appearance

What If There’s a Family History of Allergy?

If your baby has severe eczema, a known food allergy, or a strong family history of allergies, it’s best to consult with your GP, paediatrician, or dietitian before introducing high-risk allergens. In some cases, referral to an allergist or supervised introduction in a clinic may be recommended.

Final Thoughts

Introducing allergens can feel daunting, but with the right knowledge and approach, it’s a powerful way to try to prevent allergies from developing. Start early, go slowly, and stay consistent. 

I cover all things allergens and starting solids in my Starting Solids Course, available online and on-demand, the right education around infant feeding can set you up for stress-free mealtimes and a nourished child for years to come.

Want to learn more from Annabelle? You can join our Mother’s Group or contact her directly at https://dietitian.sg 
@annabelledietitian