Food Sensitivities and You: What Does the Evidence Say?

Food Sensitivities and You: What Does the Evidence Say? by Dr. Nadine Gavin ND

Food Sensitivities - Durham Natural Health Centre
Food Sensitivities – Durham Natural Health Centre


Science from the 19th century and much of the 20th century has been obsessed with universal truths. Medical science was interested in discovering the universal laws that govern how the human body functions, but over the last 20 years there has been a shift. We have moved from the search for universals to the understanding of variability. Genetics has opened the door to the study of human variability, and we have begun to realize that what works well for our neighbour may not necessarily work for us. One of the greatest areas that we see such variability is diet. Trying to “hack” diet and understand what diet will make us lose weight and feel great is a billion-dollar industry, but the lack of individualization may explain why so many diets ultimately fail. Perhaps the question should not be “What is the best diet?” but rather “What is the best diet for me?” Discovering the foods that cause inflammation and clinical symptoms in the body could guide diet choices and help manage chronic health issues, but is this promise too good to be true?

Food Sensitivities: What are they?

A Food Sensitivity is a reaction that occurs after the consumption of a particular food. When the problem food is consumed, the body produces an “IgG antibody” which binds to the food and forms a complex. This complex can build up in the tissues and trigger inflammation, which may result in a variety of symptoms. Each person can have unique food sensitivities and experience different symptoms when they consume these reactive foods. Food Sensitivities are different from food allergies and do not show up on allergy tests. Diagnosing food sensitivities can be challenging because symptoms are usually delayed hours to days after ingestion and may not occur after every exposure. Food sensitivities have been linked to numerous chronic health concerns including obesity, migraines, irritable bowel syndrome and autoimmunity.


A 2008 report looked at obese children and discovered they had significantly higher IgG antibodies to food antigens than normal weight children. They also found that anti-food IgG antibody concentrations are strongly associated with low grade systemic inflammation and narrowing of the carotid arteries. The changes are a risk factor for future heart disease. The study concluded that: “These findings raise the possibility that anti-food IgG is pathogenically involved in the development of obesity and atherosclerosis (1).”


The cause of migraine headaches is multifaceted and remains poorly understood. Recent research suggests a correlation with migraine headaches and food sensitivities. After identifying and eliminating food sensitivities, patients reported a reduction in duration, frequency, and intensity of migraines (2). This relationship was further tested by having patients complete a two week “washout period” and then consume identified foods. The trial was the first double- blinded, randomised, cross-over study on the topic and the researchers concluded IgG food sensitivity testing and food elimination was effective for migraine reduction (2). Other trials have been able to replicate this result. One such study saw a reduction in migraine headaches after 6 weeks of eliminating identified IgG food sensitivities (3). In 2019, Current Pain and Headache Reports suggested that current evidence supported IgG Food Sensitivity testing for creating customizable diets for patients to treat migraines without the use of medications (4).

Irritable Bowel Syndrome

Evidence is also increasing for irritable bowel syndrome and IgG Food Sensitivity. Several studies have shown a link between IBS and IgG hyperactivity. A recent study in 2018 offered further support for this association. After 6 months on a diet avoiding their food sensitivities, patients with IBS demonstrated improvements in stool frequency, pain relief and quality of life (5). IgG testing was also able to provide relief in IBS patients who failed to improve with standard medical treatment (6).


Individuals with Crohn’s were shown to have higher levels of IgG reactions than their healthy counterparts. Eliminating these foods resulted in improved stool frequency, abdominal discomfort and quality of life (7). IgG hyperreactivity was also seen with rheumatoid arthritis and Sjogren’s. Patients with Sjogren’s were identified to have various food hypersensitivities by IgG reactivity to these foods. Diets eliminating these foods led to resolution of symptoms that recurred with re-introduction of the food (8)

Should I get a Food Sensitivity Test?

Despite several studies confirming the association between elevated levels of IgG antibodies against food antigens and the improvement in clinical symptoms, Food Sensitivity Testing remains controversial for some allergy organizations. Concerns include using the test to diagnose an illness and the misuse of testing that results in unnecessary food restriction. IgG Food Sensitivity Testing should not be used to diagnose food allergies. Food allergies can be anaphylactic in nature and produce IgE not IgG antibodies. If you suspect a food allergy, referral to an allergist for testing is a more appropriate workup.

However, if symptoms seem to be linked to food and are not presenting like typical food allergies, in conjunction with a good work up and history taking, IgG Food Sensitivity testing may offer symptom relief for the aforementioned health conditions and should be considered.

Interpreting test results or removing suspected foods from the diet must be done responsibly. Speaking with a medical doctor, naturopathic doctor, nutritionist, or dietitian ensures dietary changes are safe, meet daily needs and are managed and re-evaluated appropriately.

If you are interested in learning more, please speak to a health care professional. Our team of Naturopathic Doctors are happy to help and work alongside your health team to provide the best care and relief for you.

Stay well!


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