Food allergies and food intolerance: the differences
About food allergies
If you have a food allergy, your immune system reacts to a particular food as though the food is toxic. Your immune system tries to protect your body by releasing chemicals like histamines into your body’s tissues. The resulting effect on the body can be quite major, even with tiny amounts of food.
Food allergies are relatively common, but severe allergic reactions to food are uncommon. And the good news is that a lot of children who have allergies grow out of them.
About food intolerance
A food intolerance is a reaction to a substance in the food you’re eating. Unlike food allergies, food intolerance isn’t caused by your immune system reacting to the food.
Diarrhoea, bloating, headaches and mouth ulcers are some of the symptoms of food intolerance.
Some people can cope with small amounts of foods they’re intolerant of, and they generally have fewer symptoms than people with allergies. Food intolerance reactions are generally less severe than allergic reactions.
It can be hard to diagnose food intolerance because the reactions to food aren’t immediate.
Common food allergies
The most common food allergies are to nine main foods:
- cow’s milk
- hen’s eggs
- tree nuts – almond, brazil, cashew and so on
Common food intolerances
The most common food intolerances are caused by:
- dairy products – for more information, see our article on lactose intolerance
- food additives, including flavour enhancers like monosodium glutamate or MSG.
Foods like strawberries and tomatoes can cause a red rash around your baby’s mouth – particularly if she has a history of eczema. This is thought to be a harmless reaction.
How long do food allergies and food intolerance last?
Most children grow out of their food allergies by adolescence, especially children who are allergic to milk, egg, soybean or wheat.
Allergies to peanuts, tree nuts, fish and shellfish are more likely to be lifelong. Allergy to gluten, known as coeliac disease, is also lifelong.
We don’t know much about how likely children are to grow out of food intolerances. How long a food intolerance lasts depends on the food and the reason your child’s body is reacting to it.
If you think your child has grown out of a food intolerance, it’s best to speak with your GP or other health professional. They might suggest you carefully introduce the food into your child’s diet at home to check whether the food intolerance has gone.
If you think your child might have grown out of an allergy, see your GP or allergy and immunology specialist for an assessment. Do not experiment at home to see whether your child has outgrown the allergy.
Allergy risk facts and factors
If a child’s parents have allergies, the child has a 40-80% risk of developing any one of the allergy problems, like asthma, eczema or hay fever. The particular risk for developing food allergy is less clear.
The allergy that a child develops might not necessarily be the same as the parents’ allergies. For example, a father with hay fever and asthma might have a child with egg allergy and eczema.
Most children with food allergy don’t have parents with food allergy. There might be a slightly higher risk, though, that siblings of a child with food allergy will also have a food allergy.
How to reduce your child’s risk of food allergies
If you have a family history of allergic disease, you can take some simple steps that might help reduce your child’s risk of developing allergies, while maintaining a healthy diet.
Eat a well-balanced and nutritious diet while pregnant or breastfeeding
Some women who have allergic diseases wonder whether they can prevent their child from developing an allergy by avoiding things that cause allergies. In general, avoiding potential allergy-causing substances while you’re pregnant or breastfeeding won’t reduce the risk of your baby developing allergies. In fact, avoiding too many foods can be dangerous, because your baby won’t get important nutrients.
The Australasian Society of Clinical Immunology and Allergy (ASCIA) recommends that you do not restrict your diet to avoid potential allergens while you’re pregnant or breastfeeding.
The Australian Government recommends breastfeeding for babies until they’re at least six months old. Keep breastfeeding for as long as it suits you and your baby, while also introducing water and solids.
Follow ASCIA guidelines for formula-fed babies
For formula-fed babies, the ASCIA infant feeding guidelines don’t recommend hydrolysed infant formula for the prevention of allergic disease. Hydrolysed formula includes partially hydrolysed formula, also called hypoallergenic formula, and extensively hydrolysed formula.
Introduce solids from around six months of age
Current Australian guidelines say you should introduce solid foods to your baby from around the age of six months, but not before four months. The introduction of solids before four months can be associated with an increased risk of food allergy. You can introduce new foods gradually (every 2-3 days). You don’t need to avoid any particular allergenic foods.
The ASCIA infant feeding guidelines say that all babies, including babies with a high allergy risk, should be given allergenic solid foods including peanut butter, cooked egg, dairy and wheat products in the first year of life. Introducing allergenic solid foods can actually protect your child against developing an allergy.