Updated: Jun 19
***This article has been written for adults, if you have a child or infant with food allergies/intolerances please book an appointment with Alex or Stephanie for a full assessment.
Recently, we’ve been seeing more and more clients come into our office with an extensively long list of food allergies, sensitivities, and intolerances. These lists are often generated by a variety of tests done by a multitude of health practitioners. Many clients report feeling surprised and overwhelmed by the long list of foods they can’t eat, and hopeless about what foods they can eat. We understand this can be frustrating! So we’re going to break down food allergies, how to test for them, and what to do after you get your results.
Firstly, it’s important to differentiate between food allergies, food sensitivities, and food intolerances as they have very different presentations and consequences.
According to Health Canada, a food sensitivity is: “an adverse reaction to a food that other people can safely eat, and includes food allergies, food intolerances, and chemical sensitivities.”
What is a Food Allergy?
Even trace amounts of a food triggers symptoms
Typically symptoms are more severe, can lead to a life-threatening condition known as anaphylaxis
May require an epinephrine injector (“Epi-Pen”)
Health Canada’s priority allergens: peanuts, tree nuts, sesame seeds, milk, egg, fish (including shellfish/crustaceans), soy, wheat, sulphites, and mustard.
According to Health Canada, only ~3-4% of adults in westernized countries have a physician-diagnosed food allergy
What is a Food Intolerance?
Amount of food ingested affects presence or severity of symptoms
Often associated with gastrointestinal symptoms: bloating, gas, abdominal pain, diarrhea, etc.
May have other symptoms as well, such as migraine headaches.
Commonly found alongside functional gastrointestinal disorders, such as IBS
Well-documented food intolerances include: lactose, fructose, alcohol, short-chain fermentable carbohydrates, and more.
According to UpToDate, food intolerances may affect ~15-20% of the population
It is important to also note that celiac disease is a genetic disease (not a food allergy or food intolerance) which causes an immunological response to gluten, with the only treatment being a lifelong, strict gluten-free diet. We will not discuss testing for celiac disease in this blog post, however please contact us if you have questions. If you have been diagnosed with celiac disease, we strongly encourage you to book an appointment with Alex or Stephanie to ensure your diet is healthy, balanced and strictly gluten-free!
How are food allergies diagnosed?
Physical exam, medical history, and detailed history of all past reactions to determine most likely trigger and mechanism. These will also inform the practitioner what test will be most helpful in determining the allergy.
Allergy tests are then selected to either confirm or rule out suspected allergies. For example, skin testing or food-specific immunoglobulin IgE (not IgG or IgG4) blood testing may be used.
Allergies are diagnosed based on a combination of history, exam, and test results.
Testing alone is not enough to diagnose a food allergy. Allergies are diagnosed through the combination of a positive test result and a consistent history of symptoms with exposure to that food. This is because it is common for people to test positive to a food but have no symptoms after ingestion - this is why it’s so important to see an allergist!
Unvalidated forms of allergy testing (aka. Avoid and save your time and money!):
Immunoglobulin IgG and IgG4 blood testing
These tests often yield multiple positive results, likely due to the body’s normal immune response to food → so these tests give lots of false positives!
Sublingual or intradermal provocation tests
Tests of lymphocyte activation
If you have questions about validated testing for food intolerances, please contact us.
Think you may have a food allergy or food intolerance? If you have one or more of these some common signs and symptoms, consult with your physician:
Nausea or vomiting
Cramping, abdominal pain, and/or diarrhea - especially if there is blood or mucus present in your stool
Itching or raised red welts on your skin
Red, warm, flushed skin
Swelling of face, lips, mouth, or throat
Wheezing, coughing, difficulty breathing
Once you have received a diagnosis, book an appointment with Alex or Stephanie to learn how to enjoy a healthy, balanced diet while eliminating any confirmed allergens or food intolerances!
Food Allergies and Intolerances (Health Canada)