The Difference between Food Allergies and Intolerances

Food allergies and intolerances may seem similar, but they are very different conditions. 
The Difference between Food Allergies and Intolerances
December 1, 2022

Both food allergies and food intolerances can share similar symptoms, but they are very different conditions. Food Handlers should take both very seriously to ensure the safe preparation and service of food.

Food Allergies 

A food allergy occurs when the body’s immune system sees a particular food as an invader and triggers an allergic reaction. When this occurs, the immune system fights the “invader” by releasing chemicals like histamine into the body. It is estimated that food allergies affect as many as 6% of young children and 3-4% of adults in westernized countries like Canada.

Allergic reactions can change very quickly from mild to severe. A severe allergic reaction is called anaphylaxis.

Allergic reaction symptoms can be life-threatening and can include the following: 

  • Skin: hives, swelling, itching, redness and warmth 
  • Gastrointestinal: pain or cramps, nausea, vomiting, diarrhea;
  • Respiratory: throat tightness or trouble swallowing, difficulty breathing, chest pain or tightness, nasal congestion or hay fever-like symptoms (runny eyes/nose, sneezing)
  • Cardiovascular: paler-than-normal skin, dizziness or lightheadedness, loss of consciousness, shock

Even a microscopic amount of the allergenic food(s) could lead to a potentially fatal reaction. Food Handlers must be trained to communicate about food allergens to customers and prevent cross-contamination from happening in the workplace. Cross-contamination occurs when an allergen is inadvertently transferred from one dish to another, often through a shared utensil, work surface, or by touch, from not properly washing items or hands between food prep.

It’s important to remember, that unlike the microorganisms that can be found in food, allergens are not removed during cooking. Food allergens are proteins (with some exceptions) and once they enter food, they become part of the dish — even if you can’t see, taste or smell them. They can’t be “killed” with high temperatures.

Food Intolerances

A food intolerance, such as lactose intolerance, means either the body cannot properly digest the food that is eaten, or that a particular food might irritate the digestive system. Symptoms of food intolerances can be caused by:

  • Preservatives 
  • Naturally-occurring food chemicals, such as:
    • Salicylates (often present in fruits and vegetables)
    • Glutamate (an amino acid found in protein-rich foods)
    • Amines (produced during fermentation, ripening and aging)

Unlike an allergy, a food intolerance does not affect the body's immune system. And while the symptoms of a food intolerance or sensitivity may cause extreme discomfort, they are generally not life-threatening.

Symptoms of food intolerance may include:

  • Abdominal pain
  • Diarrhea
  • Gas
  • Nausea
  • Headaches

A new report suggests more than 7 million Canadians are affected by food intolerance, and almost half of respondents indicated it was self-diagnosed. Some people with such food sensitivities can ingest a small amount of the problem food without experiencing too much discomfort; however, continued exposure to foods that cause damage to the small intestine can cause serious and long-term health problems, such as malnutrition, bone loss (‘osteoporosis’), bowel cancer, dental defects, irritability and depression.

Celiac Disease 

Unlike food intolerances, which do not involve the immune system, celiac disease does. Celiac disease (which is different from gluten intolerance) occurs when the immune system reacts abnormally to gluten, a protein found in wheat, rye, barley and oats, causing small bowel inflammation and damage. An estimated 1 in 100 people are affected by celiac disease, and it may be triggered at any time from birth to adulthood. It is considered neither a food allergy nor an intolerance. 

Dietary Preferences

Dietary preferences are different from food allergies and intolerances.

Someone with a dietary preference or restriction has chosen to remove certain food(s) from their diet, or has chosen to consume only foods that are prepared in a certain way or with certain ingredients.

The reasons why a person would choose to abstain from a particular food or foods are diverse, including health issues, health advice to remove a certain food from one’s diet, religious or philosophical reasons, or simply a dislike for that particular item. 

Regardless of the reasons, Food Handlers should always respect customers’ requests. And while it is possible that some customers may label a food preference as an allergy, Food Handlers must treat every allergy-related request seriously, and with the utmost attention and care, every time in order to protect customers and minimize risk of allergen-related incidents.

There are 11 priority allergens in Canada, but it’s important to note that any food or ingredient component can cause severe allergic reactions, including life-threatening anaphylaxis. Taking food allergies seriously in a food business makes it possible for thousands of people with food allergies to enjoy a safe meal in a restaurant or other food service business.

It’s extremely important that all Food Handlers:

  • Understand the ingredients and components of ingredients in the food being served
  • Have ingredient and allergen information available for customers when they ask for it
  • Record, store and communicate allergen information to all those related to food handling and service
  • Ask if they are at all unsure what is contained in a certain food
  • Be honest and forthright if the food business is unable to accommodate a customer’s needs
  • Know the policies and procedures to follow if an allergen incident should occur

Visit our Resource Library for more information and guides on food allergens, and for complete training on allergen management in your business, visit our Food Allergen Training course page.