Food intolerance

Being intolerant or sensitive to a type of food is not the same as having a food allergy. But the 2 are often confused, which can lead to issues for the person with the condition.

Learn more about food intolerance and food allergy, and how to manage both conditions.

Food intolerance, or food sensitivity, causes adverse reactions in the digestive system when you eat certain ingredients or types of food.¹

“The key difference between a food allergy and a food intolerance is that a food allergy is an immune response, whereas a food intolerance is [digestive],” says Adam Wiltgren, Bupa Dietitian.

A food allergy occurs when your immune system overreacts to a certain food, identifying it as a danger and triggering a response.²

While any food can cause an adverse reaction, common food allergens include:

• cow's milk (dairy)
• egg
• peanut
• tree nuts (such as pine nuts)
• sesame
• soy
• fish
• shellfish
• wheat.³

Food allergy can cause swelling of the face or around the mouth, skin rashes, vomiting, stomach pains and wheezing. The most severe allergic reaction is anaphylaxis, which can be life threatening.

If you think you have a food allergy, see your GP for support. If you are having a severe allergic reaction, call triple zero (000).

A food intolerance can adversely affect your health and wellbeing, although it’s usually less serious than a food allergy and not life threatening.³

Common foods people can have an intolerance to include milk and lactose, gluten and wheat. Gluten and wheat are found in foods such as cereal, pasta, jar sauces and other processed foods.

Coeliac disease is not a food allergy or food intolerance.

Symptoms of a food intolerance vary but often affect the digestive system and can include:

• stomach pain
• bloating
• gas/flatulence
• diarrhoea
• irritable bowel syndrome (IBS)
• rashes
• hives (urticaria)
• mouth ulcers
• headaches.

Food intolerance can also cause anxiety, a general feeling of ill-health, and lead to other issue such as food avoidance.

There are different ways that a dietitian can distinguish between a food allergy and intolerance. Here are Wiltgren’s top 3 signs.

“Nearly 90% of all food allergies can be isolated to fish, shellfish, peanuts, tree nuts, wheat, sesame, eggs, milk and soy,” says Wiltgren. "Intolerances can cover a broader range of foods."

“An allergic reaction will occur very soon after the person has encountered the allergen, whereas a food intolerance can take 12 to 24 hours for symptoms to appear,” says Wiltgren.

“Symptoms of an allergic reaction can occur with just a trace amount of the allergen. People with food intolerances can often eat much more of the food, sometimes over multiple days, before symptoms appear,” Wiltgren says.

Keeping a food and symptoms diary can help your health professional diagnose you.

See a GP, registered practicing dietitian or allergy specialist for help identifying whether you’re experiencing an intolerance or an allergy.

Allergy & Anaphylaxis Australia has online support resources available. You can also call for help and support on 1300 728 000.