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Is it a food intolerance or a food allergy?

An woman in her kitchen preparing food

You may have heard about some people being intolerant to a certain type of food. You may be intolerant to a certain food or ingredient yourself. But what does being intolerant really mean? Is having a food allergy the same as having an intolerance?

Although it’s easy to mix them up, intolerances and allergies are completely different reactions to food.

Read on to explore what these different reactions are and what they could mean for you.

Food intolerances

Food intolerances involve the digestive system.

They are an adverse reaction to a food or something in the food, rather than an immune system(allergic) response. In some cases, food intolerances involve the inability of the body to digest a food such as lactose.

Most food intolerances don’t generally cause severe or harmful reactions however they can affect general health and wellbeing if not managed properly.

The symptoms of food intolerance can include:

  • headaches
  • irritable bowel syndrome (IBS)
  • a runny nose
  • rashes or hives
  • uncomfortable bloating
  • stomach or bowel pain.

Some common foods or groups causing intolerances include:

  • dairy
  • caffeine
  • monosodium glutamate (MSG)
  • salicylates and amines
  • sulphites.

If you experience any symptoms of an intolerance, reach out to your doctor or a dietitian.

A woman looks at a supermarket shelf full of colourful products

Where does coeliac disease fit in?

Coeliac disease is a condition where the body’s immune system reacts to gluten. Gluten is a protein found in food made with (or containing):

  • wheat
  • barley
  • rye
  • oats.

Eating any gluten causes the small, finger-like projections (villi) in the bowel to become inflamed and flattened. Eating a gluten free diet allows the bowel wall to heal and digestion to return to normal. The only current treatment for coeliac disease is a strict life-long gluten free diet.

Food allergies

Food allergies involve the immune system.

They are due to an immune system response to substances within food.

The immune system protects us from bacteria, viruses, and other foreign invaders.

It sometimes reacts—or overreacts—to things that are not normally harmful to the body, causing an allergy. In that instance, the cause of the allergic reaction is called an allergen.

There are cells in the lining of the skin, gut, lungs, nose, and eyes called mast cells which contain special molecules called histamine and cytokines.

When an allergen is detected, mast cells are triggered to release histamine and cytokines into the tissues, causing the symptoms of an allergic reaction.

It’s important to note that severe allergic reactions can be life threatening. Seek immediate emergency treatment if you or anyone around you develops any signs or symptoms of a severe allergic reaction—anaphylaxis—see below for more information.

How common are allergies?

Food allergies are common and can occur at any age? Food allergies occur in around 5-10 per cent of children and 2-4 per cent of adults in Australia and New Zealand.

Any food that contains protein has the potential to cause allergic reactions in some individuals. However, most allergies are caused by:

  • wheat
  • peanuts
  • soy
  • cow’s milk protein (dairy)
  • eggs
  • tree nuts
  • shellfish
  • fish
  • sesame
  • lupin – or lupine/lupini is a legume related to peanuts.

What are the symptoms of an allergy?

Food allergy symptoms usually develop within a few minutes to two hours after eating the offending food, and reactions can range from mild to severe. For some people, an allergic reaction to a particular food may be uncomfortable but not severe. For other people, an allergic food reaction can be frightening and life-threatening.

The most common food allergy signs and symptoms include:

  • tingling or itching in the mouth
  • hives, itching or eczema
  • swelling of the lips, face, tongue and throat or other parts of the body
  • wheezing, nasal congestion or trouble breathing
  • abdominal pain, diarrhoea, nausea, or vomiting
  • dizziness, light-headedness, or fainting.

A large group of people having a picnic in a green field next to a river and forest

Severe reactions (anaphylaxis)

A severe allergic reaction (anaphylaxis) is a medical emergency. Call triple zero (000) immediately. Lay the person down. If they have an adrenaline injector and you are able to administer it, do so as soon as possible.

Signs and symptoms of anaphylaxis can be life-threatening and can include:

  • constriction and tightening of the airways
  • a swollen throat or the sensation of a lump in the throat that makes it difficult to breathe
  • shock with a severe drop in blood pressure
  • rapid pulse
  • dizziness, light-headedness, or loss of consciousness.

Emergency treatment is critical for anaphylaxis. Untreated, anaphylaxis can cause coma or death.

When to see a doctor

See a doctor or allergist if you have food allergy symptoms shortly after eating. If possible, see your doctor while the allergic reaction is occurring. This will help your doctor make a diagnosis.

Seek immediate emergency treatment by going to an emergency department or calling 000 if you or anyone else develops any signs or symptoms of anaphylaxis.

Read more about being allergy aware.

More information

Last updated: 21 May 2021