The Ultimate Guide to Introducing Allergens To Babies
The thought of your baby having an allergic reaction is really scary, so it’s no wonder it’s one of the biggest worries parents have when they start their baby on solids.
It’s not yet known why food allergies occur, but we do know that there are things we can do when we introduce solids to lower the risk of a food allergy developing.
So, how can we go about safely introducing ‘allergens’ (foods which cause allergies) to babies and minimising the risk of a food allergy? Let’s break it down.
Firstly, what are the most common food allergens?
Food allergy affects about 10% of babies in Australia and New Zealand (this decreases to 4-8% of children, and about 2% of adults). But, it’s reassuring to know that while some food allergies can be very serious, many of these are not severe and will disappear in time.
In Australia, the most common triggers of allergic reactions in childhood are egg, peanuts, tree nuts and cow’s milk. Other less common but still major food allergens are fish and shellfish (most common in adulthood), sesame, soy and wheat.
Most children outgrow cow’s milk, egg, soy and wheat allergies at some point throughout childhood, however peanut, tree nut, sesame and seafood allergies are usually lifelong.
When should allergens be introduced?
Up until fairly recently, parents were told to delay the introduction of allergenic foods until after 12 months to reduce the risk of allergies developing. But, thanks to a lot of research over recent years, we now know that delaying the introduction of these foods doesn’t protect against allergies, and can actually increase the risk.
Most allergens are also highly nutritious, and common ingredients in many foods, so we don’t want to be unnecessarily excluding them from a baby’s diet at a time when nutrient requirements are high.
The advice now is to introduce allergenic foods at around 6 months, when babies are developmentally ready for solids (not before 4 months), and that all babies should have these foods by 12 months. This includes babies at high risk of allergy (unless an allergy to that particular food has already been confirmed). Once allergens are introduced, continuing to give these foods regularly - around twice per week - helps to maintain tolerance.
If breastfeeding, there is some evidence - although limited - to suggest that continuing to breastfeed while introducing solids may reduce the risk of allergies and offer some protection when new foods are introduced.
How should allergens be introduced?
Allergenic foods should be introduced a few days apart so that you can more easily identify any foods your baby reacts to. They can be introduced in any order you like.
It’s a good idea to write down which foods you’ve introduced as this can help you work out what the offending food was if your baby does have a reaction.
It can also be helpful to introduce new foods at breakfast or lunchtime so that you can monitor for any reactions throughout the day.
If your baby is at high risk of a food allergy, i.e. they have an existing food allergy or severe eczema, speak to your doctor about how to introduce allergens.
NB: Never rub food on your baby’s skin as a way of testing for a food allergy. This will not help to identify a food allergy and can in fact increase the risk of an allergy to that food developing.
Ideas for introducing allergens
Below are some easy ways to introduce common allergens. Keep the following tips in mind when introducing allergens:
Start with a small amount - around 1/4 teaspoon, then increase this amount gradually with each exposure if the allergen is tolerated.
Allergens should be introduced 2-3 days apart so that if your baby does have a reaction, you can more easily identify the culprit.
• Peanuts and tree nuts – add a small amount of nut butter to porridge or thinly spread on toast (note: thickly spread nut butter can be a choking hazard). Alternatively, add a little hot water to a teaspoon of nut butter to make a warm puree. Put a little of this puree (around 1/4 tsp) on the tip of a spoon and feed it to your baby. Ground nuts and nut butters can also be added into pancakes and muffins or mixed into yoghurt. (NB: each type of tree nut will need to be introduced separately)
• Egg (well cooked - white and yolk) – a small amount of scrambled egg on a spoon (mix with milk if too thick), scrambled or mashed boiled egg thinly spread on toast. Raw egg should be avoided.
• Wheat – toast (bear in mind that many breads also contain soy), weetbix or other wheat based cereal or pasta
• Cow’s milk – porridge made with milk, white sauce (e.g. in macaroni cheese - if wheat has been introduced and tolerated)
• Sesame seeds – hummus (contains tahini which is a sesame seed paste)
• Soy – tofu (silken tofu can be stirred through puree)
• Fish and shellfish – fish pie, add mashed fish or shellfish (e.g. prawns, mussels, scallops, crab, oysters and squid) to mashed potato or vegetable puree.
NB: fish with a high mercury content such as swordfish, flake (shark) and marlin need to be avoided by babies and children. Fish and shellfish should be well cooked.
How to tell if your baby is allergic to a food
Some allergies happen quickly and are easy to pick up, for example, swelling of the face, hives, a runny nose or vomiting. Others may be delayed and less obvious such as eczema, reflux, poor growth, diarrhoea and constipation.
Many food allergies in children are not severe and will resolve themselves over time, but, some food allergies can be severe; causing life threatening reactions known as anaphylaxis.
When monitoring for possible reactions, it’s important to bear in mind that the skin on your baby’s face is very sensitive and can be easily irritated by certain foods such as citrus, tomatoes and berries. These foods can cause redness on contact but this is not an allergic reaction.
What to do if your baby has a reaction
The ASCIA 2019 guidelines state that ‘if you notice any swelling of the lips, eyes or face, hives or welts, vomiting or any change in your baby’s well-being (becoming very unsettled), soon after giving a new food, your baby could be having an allergic reaction. You should stop feeding your baby that food and seek medical advice.
Call an ambulance immediately if there are signs of a severe allergic reaction (anaphylaxis), such as difficult/noisy breathing or your baby becomes pale and floppy, or there is tongue swelling.’
The best treatment for an allergy is to avoid the food all together. With certain food allergies (e.g. milk, eggs, fish) this may mean that you need to find a replacement so that nutrient deficiencies don’t occur. A paediatric dietitian can help with this.
Allergies vs intolerances - what’s the difference?
Food intolerance is different to food allergy, as it doesn’t involve the immune system. An allergy is an over-reaction of the body’s immune system to a foreign antibody, usually a protein (whether this be a protein in food, medication, insect bites, pet hair or dust etc).
Allergic reactions to foods may be immediate - occurring within minutes of eating the food - or delayed - occurring up to 48 hours after eating the food.
Food intolerance is more common than food allergy and occurs when there is shortage of enzymes required to digest a food (e.g. lactose intolerance results when there is a shortage of lactase enzyme) or an adverse reaction to chemicals in food.
These chemicals may be naturally occurring (e.g. salicylates or amines) or artificial (e.g. additives in processed food). The extent of the reaction usually depends on the amount of the offending food eaten – a small amount may cause no symptoms at all. Food intolerance usually takes longer to present than food allergy.
Food intolerances can present in a wide variety of ways including pain, irritability and poor sleep, wind, reflux, diarrhoea, mucous in poo, greenish or frothy poos, lethargy, eczema, refusing particular foods or refusing the breast or bottle.
For more information on allergies, visit www.allergy.org.au or www.preventallergies.org.au/
Reference: ASCIA Guidelines: Infant Feeding and Allergy Prevention