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Living with Food Allergies

Food Allergy versus Food Intolerance: What’s the Difference?

Non-diary products-CDHF
Non-diary products-CDHF
Kelsey Cheyne

Kelsey Cheyne

Executive Director, Canadian Digestive Health Foundation

Some of the symptoms of a food allergy and food intolerance are similar, but the differences are significant. We know that symptoms of food intolerance can cause discomfort in the gastrointestinal (GI) tract. Still, they’re generally not life-threatening, whereas symptoms caused by a food allergy can be.

To help you understand the differences between a food allergy and food intolerance, we’ve laid them out in a handy chart.

The Canadian Digestive Health Foundation (CDHF) recommends seeing a doctor to help determine if you have an allergy or intolerance. Finding professional support, such as a registered dietitian knowledgeable in this area, can help you manage these conditions over time.

Food Intolerance

Food Allergy

What is it?

A food intolerance is an adverse reaction to a food substance or ingredient. It affects the digestive system, as it is the inability to digest or absorb certain foods.

Some food intolerances include lactose, gluten, sucrose, maltose, histamine, tyramin, and msg.

A food allergy is a reaction that involves your immune system. Your immune system is reacting to a food protein or the allergen you have ingested, which your body thinks is harmful.

The most common allergens, which are also referred to as priority allergens in food, are1: eggs, milk, mustard, peanuts, crustaceans and mollusks (shellfish), fish, sesame seeds, and soy.


Symptoms occur within a few hours after eating and may include: nausea, abdominal pain, diarrhea, bloating, vomiting, excess gas, skin rashes, and itching.

Symptoms occur within minutes of consuming even a small amount of food or a trace amount of allergen and may include: rash, hives, nausea, diarrhea, itchy skin, shortness of breath, chest pain.

Who is affected?

An estimated 6.8 to 7.4 million Canadians suffer from at least one food intolerance.2

An estimated 6.1 per cent of Canadians report having a probable food allergy.3 That’s roughly 2.3 million people. And the number may be even higher: up to 3.1 million people, according to a 2021 report from Dalhousie University.2

1 Health Canada. 2018. Common Food Allergens.

2 Dalhousie University. 2021. Dalhousie Report Allergies.

3 Health Canada. 2020. Research Related to the Prevalence of Food Allergies and Intolerances.

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