Understanding Food Sensitivities

Surrey Delta BC at Legacies Health Centre


The British Allergy Foundation suggests that up to 45%-60% of the North American population could be susceptible to a hypersensitivity or intolerance to certain foods (type III food allergies). Most people suffering from food intolerances may be unaware of their condition and tend to
ignore and even aggravate the situation since the intolerances are often associated with foods they like. Food impacts every cell in our body as the saying goes: you are what you eat. One way food can have a negative impact on the body is from food sensitivity (food intolerance).

Food allergies and food intolerances are sometimes confused with each other, but they are quite different in terms of their origin, symptoms and treatment.

Food allergy vs. food sensitivity:

Food allergies (Type I) occur in approximately only 2-5% of the population. Type I (immediate- onset) is a rather fast response (in minutes) by the body’s immune system to a perceived invader.

The immune system begins creating a specific type of antibody called IgE to certain foods. One side of IgE antibody binds to the allergic food and the other side attached to specialized immune cells called Mast cells and release histamine and other allergy-related chemicals. Sign and symptoms are typically immediate, dramatic and visible: coughing, sneezing, vomiting, watering eyes, rashes, swelling tissue, hives or in severe cases an anaphylactic shock leading to respiratory failure and death.

Food sensitivities (Type III, delayed-onset) are more common. Food sensitivity or food intolerance on the other hand is rather a slow onset reaction, taking hours, or even days. Food sensitivity also involves the immune system. They occur when immune system creates an overabundance of antibody IgG to a specific food. IgG antibodies bind directly to the food as it enters the blood stream, forming different sizes of so-called circulating immune complexes. Food sensitivity is much less likely to be life-threatening and symptoms are generally less severe than food allergy.

Since delayed-onset food allergies are so often undetected and untreated, they lie behind many chronic medical conditions of unknown cause. The allergic person suffers for years, even decades, without ever suspecting that their health problems are being caused by what they eat.

Symptoms of food intolerance:

  • Fatigue
  • Gastro-intestinal problem (bloating, IBS, IBD, constipation, flatulence, diarrhea) and 
subsequent mal-absorption problem such as anemia and osteoporosis
  • Unexplained weight gain, inability to lose weight
  • Chronic skin irritation: including acne, eczema
  • Headaches, migraines
  • Respiratory system distress: chronic sinusitis, asthma, chronic congestion

There are many ways to test for food sensitivities. The two most accurate methods that I use to test my patients are the “serum IgG testing” and “elimination diet”.

Delayed-onset food allergies are commonly reversible. Once food sensitivities have been identified, I have my patients eliminate or avoid these foods for a period of time that is determined according to one’s severity of reactions. I then work with the patient over time to reduce the reactivity to foods so they can reintroduce most foods back to their diet and remain symptom free.

Dr. Asal Shalviri ND, Naturopathic Doctor at Legacies Health Centre