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How to introduce your baby to allergen foods

Moving your baby on to solid foods can be a fun process, especially as you watch their faces as they try new flavours and textures. But it can also be nerve-wracking to introduce your baby to foods that can trigger an allergic reaction, such as peanuts or shellfish. So how can you do it safely?

For the first six months of life, babies are either




. Then, you can start to introduce them to solid foods.

Susan Nagle, a paediatric dietitian at

Dietitian Fit

, says it is important to introduce foods that may cause an allergic reaction one at a time and in very small amounts.

“This is so you can easily spot a reaction. Common foods that may cause



cow’s milk

, eggs, foods containing gluten - including wheat, barley and rye - nuts and peanuts, seeds, soya, shellfish, or fish,” she says. “There is strong evidence to say that delaying the introduction of these foods may increase the likelihood of developing an allergy.”

A review published in 2023 of more than 4,000 articles and 32 reviews concluded that the introduction of certain food allergens before the age of 11 months could decrease the likelihood of developing some food allergies1.

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What if your baby already has a diagnosed allergy?

If your baby has a diagnosed allergy, such as a cow’s milk allergy, this may mean they’re more likely to have other allergies. However, it’s important not to panic - it just means you’ll need to be particularly careful when introducing foods. Before you start weaning, speak to your health visitor or GP as they will be able to offer advice and support.

“Take note of any family history of allergies as this may increase the likelihood of your baby having them,” says Nagle. “If your baby is allergic to any type of food, remember to read labels carefully and avoid foods if you’re unsure.”

Sometimes, it can be easy to miss ingredients that your child is allergic to, such as milk powder.

How to introduce your baby to allergenic foods

When introducing your baby to allergens - foods that may trigger an allergic reaction - start off with one type of food at a time and in small amounts. This means you can easily spot a reaction.

“Try getting your baby to taste a small spoon of the food. For example, yoghurt, cereal, cooked fish or scrambled egg,” says Nagle.

Nuts, peanuts and seeds should be served crushed or ground and shellfish and fish should be properly cooked through. You could also try giving your child a small amount of peanut butter on a teaspoon.

“Once introduced and tolerated, these can be included as part of your baby’s diet from six months of age,” adds Nagle.

Although it can be scary to introduce peanuts or eggs to your baby, research suggests delaying it may increase the risk of developing an allergy to these foods1.

Although lots of children outgrow their allergies to cow’s milk or eggs, studies suggest a peanut allergy may be more likely to be lifelong. According to the charity Anaphylaxis UK, between 10 and 20 percent of children may outgrow a peanut allergy3.

What are the signs of an allergic reaction and what should you do?

Most reactions occur within a few minutes of being exposed to an allergen. They can include




and red or itchy eyes. Symptoms also include a


, worsening of




and a runny or

blocked nose

. They may also get

stomach aches

or sickness.

Sometimes, a severe reaction may occur called anaphylaxis or anaphylactic shock, which is a severe and potentially life-threatening reaction to an allergy. This is a medical emergency and requires urgent medical attention - call for an emergency ambulance - 999 in the UK. The signs include feeling lightheaded or faint, breathing difficulties, wheezing, a fast heartbeat, clammy skin, confusion, anxiety and losing consciousness. If in doubt, it’s important to seek medical attention quickly.

“Don’t be tempted to experiment by cutting out a major food if you’re concerned about allergies. This could lead to your child not getting the nutrients they need,” says Nagle.

If your child does have an allergic reaction to a food, stop giving them it and speak to your doctor or health visitor. They will be able to provide a diagnosis, advice and support, or refer you to an allergy specialist.

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Further reading

  1. Soriano et al: Complementary and Allergenic Food Introduction in Infants: An Umbrella Review.

  2. Anaphylaxis UK: Peanut allergy and tree nut allergy.

Article history

The information on this page is peer reviewed by qualified clinicians.

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