Food allergies in babies: the latest approach

Introducing your child to common allergy-causing foods early could actually help prevent a food allergy. 

Words by Bonnie Bayley
July 2019

Food allergies seem to be more common these days. Most of us know someone who can’t eat wheat, dairy, peanuts, soy, sesame, seafood or some other trigger food. If you have a baby, introducing these foods can seem overwhelming and a little scary, particularly if you have allergies yourself.

But the medical community has shifted its thinking considerably in recent decades. While the old school of thought was that parents should delay the introduction of allergenic foods, experts now believe that earlier introduction of these foods may help prevent food allergies in babies.

The new thinking

The latest infant feeding guidelines, released in January 2019 by the Australasian Society of Clinical Immunology and Allergy, recommend parents introduce babies to allergenic foods like egg and peanut by 12 months. This is the case even if a baby is at increased risk of an allergic reaction, for example, if they have eczema, asthma, an existing food allergy or an affected family member.

“What we’ve found in research from all around the world is that when the introduction of allergenic foods is delayed, there’s [an associated] rise in food allergies, particularly peanut allergies,” explains Dr Preeti Joshi, staff specialist at the Department of Allergy and Immunology at The Children’s Hospital, Westmead.

Immune advantage

So why does eating allergenic foods help prevent food allergies in babies? It may be that early introduction of allergenic foods capitalises on the immune system’s most adaptable period.

“If you expose someone early, you may be able to skew their immune system towards tolerating these foods,” explains Dr Joshi.

There’s also the theory that it’s better to be exposed to allergens through the digestive system first.

“As you get older, you may be exposed to allergens such as peanut oil through your skin,” says Dr Joshi. “That may be one of the reasons a child’s body starts to respond abnormally, because it’s getting exposure through broken skin instead of through the gut, which contains bacteria that help us tolerate the world around us.”

How to approach allergenic foods

You can start your baby on solid foods between four to six months old, says GP Dr Preeya Alexander.

“Parents need to watch for signs of readiness in their child to know when it’s time to start solids; the infant ideally needs to have good head control and an interest in food.”

Introduce allergenic foods by 12 months suggests Dr Alexander. There isn’t any particular order in which allergenic foods should be introduced – for instance, there’s no need to start with cow’s milk and wheat, and ‘build up’ to egg, peanut and fish.

“Go with whatever you like, as long as you’re introducing it,” encourages Dr Alexander.

Australasian Society of Clinical Immunology and Allergy’s guidelines suggest you:

Start small: “Start with a small amount and if tolerated, you can continue to gradually give larger amounts if there are no reactions,” says Dr Alexander.

With egg and peanut, start by rubbing a small amount of well-cooked egg or peanut butter inside bub’s lip. If they tolerate it, try ¼ teaspoon next, then ½ teaspoon, and so on. Stick to nut paste (instead of whole nuts or pieces) to avoid the risk of choking.

Space out allergenic foods: Introduce one new food at each mealtime, so that if an allergic reaction occurs, it’s easier to pinpoint the culprit.

Be consistent: serving an allergenic food once (particularly peanuts) isn’t enough.

“You’ve got to do it two to three times a week to keep teaching the immune system that it’s tolerant to that food,” says Dr Joshi.

Seek expert guidance if necessary: If your baby has severe eczema or already has allergies before starting solids, chat to your GP before you introduce allergenic foods, to make sure it’s done as safely as possible.

Recognising an allergic response

Symptoms of food allergy include:

• swelling of the lips, eyes or face
• hives or welts
• vomiting
• the baby becoming very unsettled.

If this happens, remove the food and see your GP to check if there’s an underlying allergy.

If there’s a severe reaction, such as tongue swelling, your baby becomes pale or floppy or has difficult/noisy breathing, call an ambulance immediately.

“The majority of kids develop the first signs of an allergic reaction within half an hour of ingestion of the food, sometimes up to 2 hours. So if they develop a rash the day after, it probably isn’t that food,” says Dr Joshi.