Understanding Food Sensitivity vs food allergies vs food intolerances: What It Is? How to Identify It? Is food sensitivity test IgG blood test accurate?

Understanding Food Sensitivity: What It Is, How to Identify It?

In recent years, food sensitivity has become a hot topic in the world of health and wellness. Food sensitivity is different from food allergies. For food allergies, it triggers an immediate immune response to food proteins. Our body treats the specific food protein as harmful, and our body can develop allergic reactions. A common type of food allergy is that the immune system makes Immunoglobulin E (IgE antibodies), and this IgE antibodies signals the immunes system to release a large amount of histamine. The allergic reaction can include swelling, hives, coughing, wheezing, vomiting, breathing difficulty, etc. 

What is food sensitivity?

Food sensitivity is an umbrella term, and it can include adverse food reactions including food allergy, celiac disease, irritable bowl syndrome, food intolerances, chemical sensitivity, etc.

What is chemical sensitivity?

Some clients cannot tolerate caffeine in coffee or tyramine in aged cheese. These are examples for chemical sensitivity.

What is food intolerance?

Food intolerance usually doesn't involve a person's immune system. For intolerance symptoms, it usually includes GI issues such as bloating and diarrhea. Food intolerance usually refers to our body not being able to digest certain food. A common example that I often see in my clients is lactose intolerance. Some people feel quite bloated when having dairy products.

What is celiac disease?

Celiac disease is a genetic autoimmune disorder in which the ingestion of gluten leads to the damage in the small intestine. Gluten is a protein found in wheat, barley, and rye. When individuals with celiac disease consume gluten, their immune system responds by attacking the small intestine, specifically targeting the villi, which are small finger-like projections that line the intestine and promote nutrient absorption. Individuals need to avoid gluten if having celiac diseases.

How to diagnose food allergy? What are some examples for food allergy tests available in Canada?

Diagnosing a food allergy in Canada involves a medical team such as doctors, allergist, and health professionals. A combination of medical history, physical examination, testing suspected food, and specific diagnostic tests are used for proper diagnosis.

1. Medical History and Physical Examination

• Detailed History: The healthcare provider will take a detailed medical history, including symptoms, timing of reactions, types of foods suspected, and family history of allergies.

• Physical Examination: A physical exam may be done to check for signs of an allergic reaction or other conditions that could cause similar symptoms.

2. Skin Prick Test (SPT)

• Procedure: Small amounts of suspected allergens are placed on the skin, usually the forearm or back. The skin is then pricked to allow the allergen to enter the skin.

• Interpretation: If a raised bump (wheal) surrounded by redness (flare) develops, it may indicate an allergy, and the results need to be properly interpreted with a doctor or allergist.

3. Blood Tests

• Specific IgE Testing: Blood tests can measure the presence of specific IgE antibodies to foods.

• Interpretation: Higher levels of specific IgE antibodies to a particular food may indicate an allergy, and the results need to be properly interpreted with a doctor or allergist.

  
  

What is IgG antibody testing?

IgG antibody testing is a type of blood test that measures the levels of Immunoglobulin G (IgG) antibodies in response to specific foods. Some practitioners claim that having food-specific IgG antibodies means this is a food allergy or sensitivity and suggesting that these foods should be eliminated from the diet. Some clients can feel quite frustrated that they need to avoid a long list of food that they normally enjoy. However, there is limited scientific evidence to support the use of IgG antibody testing for diagnosing food sensitivities. The clinical relevance of IgG antibody testing is controversial. Many health professionals argue that the presence of IgG antibodies to foods is a normal immune response and does not necessarily indicate a sensitivity or intolerance. If clients avoid too many food unnecessarily, it may affect the quality of life and also potentially limiting nutrients intake in the diet.

Final Thoughts

Food sensitivity is a complex. It is important to consult a doctor, allergist, and dietitians. Doctors or allergist sometimes may do an oral food challenge to see whether the allergic reaction happens and assess the dosage. Oral food challenges need to be medically supervised by doctors or allergist. Dietitians can be great support for clients to do meal planning, label reading, and understanding what needs to be properly avoided or included in the diet for our health.

Cheers,

Elaine Vancouver Dietitian

Disclaimer: This blog is for informational purposes only and is not a substitute for professional medical advice. Always consult a healthcare provider before making significant changes to your diet.

References:

Government of Canada. Food Allergies and Intolerances. Retrieved March 4, 2025, from

https://www.canada.ca/en/health-canada/services/food-nutrition/food-safety/food-allergies-intolerances.html

Healthlink BC. Food Allergy Testing. Retrieved March 4, 2025, from www.healthlinkbc.ca/sites/default/files/healthyeating/pdf/food-allergy-testing-en.pdf