IgG Food Intolerance
A valuable tool often used to help design elimination diets for patients with several chronic conditions.

Food IgG Intolerance Testing

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Clients may come to see you with the assumption that a food allergy and a food intolerance are one and the same. It is very important to explain the differences between an allergy and an intolerance.

A food allergy is an immune reaction that results in the production of IgE antibodies. The reactions are usually immediate and symptoms can range from rashes, swelling, violent sickness, difficulty breathing and anaphylactic shock.

Food intolerances that are immune related result in the production of IgG antibodies and symptoms are usually not as severe and may not appear for several days.

With a food allergy, it is important to continue avoiding that food, regardless of the test results obtained in the Food IgG Intolerance Test.

This advice also applies if the patient has been diagnosed with Celiac disease or any other food related conditions such as lactose intolerance.


It is important to understand the role that cross-reactivity plays in the interpretation of results. Cross-reactivity occurs when the immune system reacts to a protein that is similar or identical to a protein of other foods or pollens. These are known as panallergens. If there is a 70% similarity, a cross-reactivity can lead to an increased result, even if the patient has not consumed the particular food. These reactions should not be considered a false positive, as these results may be a reflection of a pattern of clinical sensitivities including the possibility of a pollen sensitivity. Current publications focus on IgE antibodies, but given the relationship between IgE and IgG antibodies, cross reactivities can overlap between the two antibodies. For example, it has been shown that birch pollen can have a cross reactivity with peanut, hazelnut, potato, soy and almonds or foods that contain similar storage proteins, such as peanut, lentil, soy, pea and walnut can have a cross reactivity.

The Importance of Testing

The prevalence of IgG mediated Food intolerances are believed to impact 5 – 20% of the population, even as high as 50% in studies in certain diseases, such as IBS. IgG antibodies are the main line of acquired defence and the body’s specific response to pathogens. In normal conditions, the digestive system does not allow food particles to pass through, but when there is damage, small fragments of partially digested or undigested food particles pass into the bloodstream. The particles are recognized by the immune system as pathogenic or foreign and activate the production of specific IgG antibodies. The food particles (antigens) combine with the specific IgG antibodies to create antigen-antibody immune complexes. Normally these are removed by the immune system, but if the immune system becomes overloaded or compromised, the sIgG antibody-antigen complexes circulate in the bloodstream and can accumulate in joints and organs causing chronic inflammation and subsequent production of symptoms. These symptoms can take days to months to manifest; therefore, it is difficult to identify the offending foods. Food sensitivities, if not treated, can have a significant impact on the quality of life of patients and their families.


The Food specific IgG Intolerance test detects antibodies to over 220 foods, identifying the common culprits and providing valuable information on the unexpected intolerance. The test is performed using the ELISA (Enzyme-Linked Immunosorbent Assay) method. The extracts of the foods used for testing are prepared in a qualified laboratory. Positive and negative controls are run with each patient sample and each food is tested in duplicate, providing accurate results you can trust.

Results You and Your Clients Can Understand

The food intolerance report is a quantitative measurement of the intolerances to specific foods. The report uses a traffic style report, red means the food should be eliminated for a period of 3 – 6 months and yellow suggests foods that should be reduced or rotated, green is normal. The quantitative values can be used to plan an optimum elimination diet, eliminating the highest values for the longest period. The report is issued in two formats, one by reactivity and the other report by food group along with a guide on how to use the results.

The efficacy of a diet based on the measurement of IgG antibodies specific for food components has been demonstrated in several health conditions, both in independent studies and clinical practice. Excellent results have been obtained in patients with migraine, IBS, bloating, asthma, dermatitis, tiredness, and obesity.

For a deeper dive into Food IgG Intolerance, watch the recording of our webinar "Food Intolerances - the Unexpected Result” here.