About food intolerance
A food intolerance is a reaction to the food you’re eating. The reaction might be because your body can’t properly break down the food. Or it might be because your body is irritated by a chemical that’s in or added to the food.
Some people can cope with small amounts of foods they’re intolerant of.
Food intolerances aren’t the same as food allergies. Food allergies happen when your immune system reacts to a food you’ve eaten. Food intolerances don’t involve your immune system. Food allergies are generally more severe and have more symptoms than food intolerances.
Symptoms of food intolerance
Symptoms of food intolerance include:
Food intolerance symptoms are often delayed. They can appear hours to days after you’ve eaten the food you’re intolerant of.
If you think your child has food intolerance or you’re not sure why your child is having symptoms, it’s best to talk with your GP. Your GP can help you rule out conditions like reflux or other gut problems, which can cause symptoms like those caused by food intolerance.
Common food intolerances
The most common food intolerances are to:
- lactose, which is the sugar in cow’s milk and dairy products
- food additives, including artificial preservatives and flavour enhancers like MSG
- fructose, which is the sugar in fruit
- naturally occurring food chemicals like salicylates and amines.
Assessment and diagnosis of food intolerance
Elimination diets are the most common test for food intolerance.
An elimination diet involves removing foods that might cause intolerance from your child’s diet. You remove the food for a period of time, usually a few weeks. Then you reintroduce foods one at a time to work out which food is causing the intolerance. You might keep a food diary to work out which food is causing your child’s symptoms.
It’s best to speak to your GP or a dietitian before starting your child on an elimination diet. They’ll ensure that your child’s diet continues to give your child the nutrition they need for growth and development, even while you’re eliminating things from it.
For suspected fructose or lactose intolerance, doctors might also use a breath test. Your child drinks a standard amount of lactose, and then the amount of hydrogen gas in your child’s breath is measured. Lactose-intolerant children will have higher levels of hydrogen in their breath.
Allergy testing doesn’t help with diagnosing food intolerance. It’s always best to see your GP if you think your child has a food intolerance. Your GP can explain the most appropriate test for your child.
What to do about food intolerance
If a doctor has diagnosed food intolerance in your child, the doctor might recommend that your child:
- eats less of the food causing the intolerance
- avoids the food altogether.
If your child eats something that you know they’re intolerant of and they get symptoms of intolerance, the symptoms will usually clear up by themselves over time. Your child shouldn’t need urgent medical attention.
If your child’s symptoms include diarrhoea, you need to make sure that they get plenty of water or fluids. This will help your child to avoid dehydration.
How long do food intolerances last?
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 dietitian. They might suggest you carefully reintroduce the food into your child’s diet at home to check whether the food intolerance has gone.