IgG food sensitivity testing is sometimes used in clinical practice to explore delayed reactions to foods that may contribute to digestive symptoms and inflammation. Unlike immediate food allergies, these responses can be more subtle and harder to identify. However, the use of IgG testing remains debated, with differing views on how results should be interpreted. In practice, testing is often considered alongside clinical history, symptoms and dietary response, rather than as a standalone diagnostic tool. Understanding both its applications and limitations is essential for a balanced approach to gut health.
What is IgG food sensitivity testing?
IgG food sensitivity testing is a method that measures Immunoglobulin G (IgG) antibodies produced as part of the immune system’s response to exposure to foods. This type of testing is often used as a way to identify food sensitivities or intolerances. However, at present it is not considered reliable for diagnosing food allergies or sensitivities by many medical organisations.
I have utilised IgG testing for many years in clinical practice and find it a useful tool to help clients with putting together elimination diets based on the test results. Therefore, any views expressed by me re IgG testing presented ain this post based on clinical experience and applications that were life changing in some cases, backed by a number of case studies and an actual clinical sIgG testing study conducted over 3 years.
Why food sensitivities are becoming more common in both adults and children
Recent studies have found that approximately 15-20% of adults experience food sensitivities or allergies. Of these only a small percentage are in fact severe allergies (called anaphylactic reactions) mediated by Immunoglobulin type E (IgE). Most common are food sensitivities mediated by the Immunoglobulin type G (IgG), characterised by the delayed response food reactions i.e taking 1-3+ days to appear.
As a Wholistic Natural Therapist, I focus on good nutrition as a baseline of health, therefore I consider identifying food sensitivities/ intolerances as a key step in helping clients to get better. My personal and clinical experience as well as feedback from other practitioners confirm that incidence of food sensitivities is on the rise due to a number of factors.
These include microbiome imbalances, having a leaky gut syndrome, impaired digestion (low stomach acid and digestive enzymes), food contamination with chemicals and pesticides (especially glyphosate which is implicated in leaky gut), and many more.
Having taken multiple medications for years without improvements, many clients with chronic conditions are making different therapeutic choices nowadays. They are applying nutrition, tailored supplementation and lifestyle modifications as potential solutions to their complex health problems, rather than solely relying on the prescription drugs.
In my clinical experience and according to many research studies, there’s validity to and reliability of the ELISA (enzyme-linked immunosorbant assay) testing for IgG-mediated food sensitivities. Undertaking an elimination diet based on the test results, can be a useful aid to the management of or recovery from many diseases. An elimination diet involves temporarily removing selected foods and then systematically reintroducing them to observe any changes in symptoms.
I teamed up with Nicholas Greene, a holistic Chiropractor at Greene Chiropractic, who also utilises IgG food sensitivities testing to help solve challenging or complex cases, with impressive results. I help his patients who took the test to interpret the results and to follow the elimination diet, making sure all food groups are present to avoid any nutrient deficiencies, and support their digestion, if required.
How IgG testing differs from food allergy testing
Immunoglobulins (also known as antibodies) are proteins produced by the immune system, in particular white blood cells, that are manufactured in response to foreign bodies entering the body via the mucosal surfaces of the body i.e. the digestive tract including gut lining, mouth and nasal passages.
There are several types of immunoglobulins (Ig) that have different functions, with IgA, IgE, IgG, IgM being the most known. IgG is the most common antibody produced by the body.
Although these terms all relate to an adverse physiological response to a particular food, the mechanisms by which this occurs are very specific to the type of food sensitivity in question. These reactions can be categorised as either:
- Immunological i.e. involving the immune system (IgE or IgG mediated), or
- Non-immunological – where there is no immune system involvement
Identifying the specific reactive mechanism triggered by the ingestion of a problematic food is vital to understanding the management and implementation of appropriate dietary interventions to limit or eliminate potentially unpleasant, and in some cases, life threatening, symptoms.
Allergic reactions (i.e. IgE-mediated reactions) and intolerances/sensitivities (IgG-mediated reactions) are both immune responses to an irritant. However, their mechanisms of action and presentations are quite different. Food allergies typically involve immediate immune reactions, while food sensitivities are more often associated with delayed responses that can occur hours or even days after exposure.
Immunological reactions
IgE food allergy (immediate hypersensitivity response)
More commonly known as a food allergy, this reaction typically occurs very quickly (within minutes to hours) after eating a particular food, with symptoms ranging from mild to severe (e.g. anaphylactic reaction to peanuts). Milder symptoms may include itchy lips/tongue/throat, stuffy nose, headaches, stomach pain, diarrhoea, gas, bloating, skin reactions, and sudden fatigue.
Most people know their ‘trigger foods’ because when the reaction occurs, it’s quick and happens soon after eating food.
Important: IgE allergy is not identified by the IgG-mediated food insensitivity tests. If you suspect you may have an IgE allergy, then they should consult your doctor to be tested for this.
The IgG type of hypersensitivity is called food sensitivity or intolerance. The signs and symptoms are delayed and develop within 8–72+ hours after ingestion of the problematic food. Sensitivity reactions occur when a certain food is ingested and antibody-antigen (also known as immune complexes) form with proteins in that food.
IgG food sensitivities (delayed hypersensitivity response)
Normally these complexes are eliminated by the immune system with no ill effects. However, if the immune or digestive systems are compromised, these complexes keep circulating in the blood and, when unable to be removed, can be deposited in tissues or organs causing an inflammatory response and/or tissue damage, subsequently producing symptoms. Symptoms can last for several days or longer and are often intermittent, making it difficult to identify which foods your body is struggling to deal with.
Other types of food intolerances: Non-immune mediated food intolerances
Unlike in IgG food intolerances or IgE mediated food allergies, there are other food sensitivities where the immune system isn’t involved. Examples of this type of intolerances include:
- Enzyme deficiencies – such as lactose intolerance caused by the absence of enzyme lactase
- Histamine intolerance – can be caused by enzyme diamine oxidase (DAO) deficiency
- Fructose intolerance – occuring when the body’s digestive system doesn’t absorb fructose properly
- Amines – are compounds known for their strong, pungent odours. They are found, for example in deli meats such as salami, bacon, ham and frankfurts, tinned fish and meats
- Salicylates – naturally present in many fruits, vegetables, seeds and nuts
- Food additives, either natural and artificial used to flavour and preserve food, such as sodium benzoate, sulphites (a preservative found in dried fruit and vegetables) and monosodium glutamate (MSG)
What are the causes of IgG food sensitivity
There are several proposed causes of food sensitivities and research suggests that poor gut and immune health may be responsible.
Other causes of IgG responses identified in studies include:
- Loss of or impaired immune tolerance – when the immune system appropriately responds to the environment i.e. it doesn’t over react or under react to the foods you eat, chemicals, and our own tissues (autoimmunity). When you have a good immune tolerance you don’t have food intolerances, chemical sensitivities or autoimmune disease. However, if you lose immune tolerance, the immune system becomes over active. It starts reacting to multiple foods, detergents, skin creams, perfumes, car fumes or jewellery, among others.
- Altered microbiome – changes in gut microbiota (especially decrease in bacteria diversity) may alter interactions with and activation of the immune system, thus increasing tendency to developing food intolerances. Reduced levels of beneficial bacteria in the gut can predispose individuals to increased incidence of developing bacterial and viral infections.
- Leaky gut – or increased intestinal permeability to larger proteins, results in elevated concentrations of IgG antibodies due to an immunological reaction being triggered.
- Viral infections – studies have identified viral infections as a factor that can increase susceptibility to developing food sensitivities by breaking down oral tolerance to dietary proteins.
- Bacterial and parasitic infections – may also suppress immune responses by triggering inflammation, impairing gut permeability (leaky gut) and thus facilitating the development of food sensitivity.
- Various factors such as genetics, environment, diet and antibiotic intake, may all contribute to alteration of the gut microbiota and therefore to compromised immune function, ultimately affecting potential development of food intolerance.
What symptoms and conditions are associated with IgG food sensitivity (examples)
There are many conditions and symptoms that may be exacerbated by food intolerances, including:
- Weight gain – increased weight and obesity appear to be another causal factor in the development of food intolerance. Inflammation contributes to increased intestinal gut wall permeability (leaky gut), thus potentially elevating levels of IgG antibodies to foods in the blood stream. One effective approach to managing weight gain/ obesity is to eliminate foods that are IgG reactive and replace them with similar, non-reactive foods to ensure that nutrient deficiencies don’t occur.
- Chronic disease – food intolerances are one of the contributing factors to developing a chronic disease, hence IgG
antibodies may contribute to the development of conditions such as IBS, obesity, type I diabetes and migraines. - Migraines – while the exact causes of migraines are still unclear, a number of hypotheses have been proposed to explain possible causes. Studies have shown that food sensitivities are likely to be a contributing factor or late allergy reaction in migraines, mediated by IgG. There is growing evidence suggesting that inflammation plays an important role in the pathogenesis of migraine. It’s this pro-inflammatory response of food sensitivity reactions that is believed to contribute to symptoms of migraines.
How IgG testing is used in clinical practice
The efficacy of a diet based on the measurement of IgG antibodies to specific foods has been demonstrated in a number of conditions, both in independent studies and in clinical practice. As mentioned above, to date good results have been obtained in people with migraine, IBS and obesity.
We know that certain common foods such as wheat, dairy or eggs are more likely to show a positive result. It’s because these foods are consumed on a regular basis in the diet, often eaten daily in multiple meals and, along with digestive issues, this can increase the likelihood of the immune system reacting to them.
The benefit of doing a food sensitivity test is that it will be able to quickly identify which of the foods that are eaten on a regular basis are a problem.
In addition, the test is able to highlight more foods such as so called ‘superfoods’ or just ‘healthy’ foods, which a person may not have considered removing from their diet. For example, lately I find avocado is marked as problematic for some people, likely because they eat avocados on a daily basis and thus can become intolerant.
Overall, IgG food intolerances have been linked to various symptoms and disorders, yet diagnosis can be quite challenging. As mentioned, symptoms are often delayed in presentation and are intermittent (not occurring after every exposure to the allergen). In practice, results are most useful when interpreted alongside symptom patterns and response to dietary modification.
Given the limitations of testing, dietary approaches such as elimination diets are often used to help clarify individual responses to foods.
The role of elimination diets
Importantly, IgG food sensitivities testing is a valuable tool for practitioners, helping to create personalised dietary recommendations and reducing guesswork in developing effective therapies. These involve healing the gut wall and balancing the microbiome, decreasing inflammation and resetting the immune system.
Testing also helps clients to be more motivated and confident they are actively helping the body to remove obstacles to healing or getting better.
Limitations and controversies of IgG testing
IgG food sensitivity testing remains an area of ongoing debate. Some research suggests that IgG antibodies may reflect exposure to foods rather than intolerance. For this reason, results should not be interpreted in isolation. A more reliable approach utilised in my practice combines testing with clinical assessment, symptom tracking and structured dietary interventions such as elimination diets.
The main controversy surrounding food IgG testing relates to the significance of food IgG antibodies in the development and diagnosis of food intolerances in chronic illnesses such as inflammatory bowel disease (IBD), IBS, migraine or arthritis.
Often, people don’t associate a given symptom with the food they ate, especially because of the lack of the characteristic ‘allergic’ symptoms. This is the chief argument that highlights the controversial nature of this type of food intolerance.
However, a number of clinical studies to date, have in fact been supportive of a role for food IgG testing in certain diseases and its importance in clinical results.
How does the IgG test work?
The process is as follows: Food extracts are ‘printed’ onto ‘pads’ on a glass microscope slide, together with calibration standards and controls. A blood sample provided by the patient is diluted and dispensed onto each printed microarray.
Food IgG antibodies, if present, bind to the food extracts and the results are measured by a high-resolution scanner, before being calibrated against the standards using a specific software to give quantitative results. This software then produces a tailor-made printout of the final food IgG antibody result for each food on the requested food panel.
A sensitivity reaction to a food usually doesn’t mean that it will need to be avoided forever, although it may take quite some time before it can be eaten again. As the test indicates food sensitivity reactions to the foods you’re eating at present, you’d need to repeat the test after at least 6+ months to gauge which foods have been ‘corrected’ and can be slowly re-introduced after their avoidance.
Cautions and considerations
IgG food sensitivities testing is not recommended for:
- Pregnant women – generally a food intolerance test is not recommended during pregnancy because as the immune system is suppressed. However, 4-6 weeks after giving birth should be OK to test.
- Children under the age of 2 years – Cambridge Nutritional Sciences don’t recommend testing on children under the age of 2 years. They base this on the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition Guidelines for the Diagnosis of Coeliac Disease 2012, which states that there is a possibility of false negative results occurring in infants younger than 2 years of age. This related to the fact that the infant gut is more permeable than that of an adult, coupled with immature mucosal immunity that is still in the learning and development stage.
- People taking immunosuppressants – avoid immunosuppressant medications, if possible, before the test, as they may have an impact upon the results.
Important: IgG food sensitivity antibody test does NOT test for classical allergies, which involve the production of IgE antibodies and cause rapid-onset of symptoms such as rashes, swelling, violent sickness, difficulty breathing and anaphylactic shock. If you have a food allergy, it’s important to continue avoiding that food(s), regardless of the IgG test results obtained. This advice also applies if you have been diagnosed with Coeliac disease or any other food related condition such as lactose intolerance. The test results are discussed in details with each client to prevent any misunderstandings or errors.
How to do the IgG food sensitivities test in Australia?
It’s simple! After I refer a client for the IgG food intolerances testing, he/she then needs to either visit a blood collection centre or perform an “at home” test using a test kit provided by the lab. The results are sent to me and then forwarded to clients for discussion and implementation. Together, we develop and implement a tailored and doable nutrition plan to follow for around 6 months, including detailed nutrition plans, menus, shopping lists, eating out recommendations etc.
Regular nutrition help and coaching is an important part of the therapy to keep clients on track, remove obstacles as we go and manage any related stress.
When the results show many foods as reactive it’s important to consider a likely presence of underlying leaky gut syndrome. In such cases, gut repair protocol is a useful tool to implement along with the elimination diet.
FAQ
A test that measures IgG antibodies to foods to explore possible delayed reactions.
Its accuracy and interpretation are debated, and results should be used alongside clinical assessment.
Food allergies involve immediate immune responses, while sensitivities are typically delayed sometimes for days.
No, it should be used as part of a broader clinical approach and interpreted by a knowledable practitioner.
Yes, they may contribute to inflammation and digestive symptoms in some individuals.
Next steps
Food sensitivity testing may provide useful insights when interpreted carefully within a broader clinical framework that includes symptoms, dietary response and overall gut health.
Please note that t present I’m able to consult with Australia-based clients only.
To book a consultation, either via Zoom or phone click the button below. I also offer a free 20-minute initial discussion to talk about your circumstances and how I can help.
Make that call. It could change your life!
IgG food sensitivity: list of all case study reports
We have seen many positive results and health transformations in many of our clients after IgG testing and following the elimination diet. Subsequently, Nicholas Greene, Chiropractor and I conducted a clinical study on the applications of IgG food sensitivities testing and elimination diet for our clients suffering from the following classes of conditions:
- Obesity/ overweight – read case study reports here:
- Gut disorders – read case study reports here:
- Autoimmune conditions – read case study reports here:
- Autoimmunity and food sensitivities – a case study
- Resolving pain, inflammation and arthritis – a case study
- Skin conditions – read case study reports here:
- Hormone imbalances – read case study here:
Summaries of all case studies can also be found HERE.
Read the fully referenced clinical study HERE.
Clinical study report and results
Our clinical study is now complete. It took us over two years to collect and analyse the data, and to write up a fully referenced and statistically analysed clinical study, but the patient health improvements achieved are all worth it! We are not aware of any such research undertaken to date, i.e. primarily based on the clinical experience/ evidence. Here’s the link to the full study:
Study title: “Therapeutic use of IgG food sensitivity testing and elimination diet as an effective approach to patient’s care”
Study authors: Joanna Sochan and Dr Nicholas Greene
Read this post for the study summary and results presentation.
We hope our findings will contribute to dispelling some of the controversies surrounding IgG testing, and will help to broaden its applications to help more people getting healthier and happier.
Best of Health
Joanna Sochan
Wholistic Health and Lifestyle Therapist
Natural and Lifestyle Therapies for Abundant Health and Wellbeing
References
- BeFunctional Lab
- Dietary advice based on food specific IgG results Geoffrey Hardman, Gillian Hart, University of York, Heslington, York, UK Nutrition and food science vol 37 no 1 2007 pp16-23
Additional resources
- Histamine intolerance: causes and treatment
- Secretory Immunoglobulin A (sIgA) for healthy gut, digestion and immunity
- Psoriasis: a holistic approach to recovery
- Top nutrition tips for insomnia or interrupted sleep
Disclaimer: The above material is for informational and educational purposes only. It should not be used to self-diagnose and it is not a substitute for medical advice, diagnosis, treatment, prescription or recommendation. All viewers of this content, especially those taking prescription or over-the-counter medications, should not make any changes in their health regimen or diet before first consulting a doctor or other qualified health provider with any questions they may have regarding a medical condition or their particular circumstances.
Joanna Sochan is a Natural Therapist and founder of Naturimedica Holistic Wellcare. She has a passion for helping clients transform their lives by becoming healthy and well naturally. Joanna has 15+ years experience in clinical practice and has special interest in solving complex cases, gut health, food sensitivities, hormone imbalances, and weight loss. She helps clients individually (mostly online) Australia-wide and also offers online therapeutic programs, eCourses and self-help books. View full bio.
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