The IgG  Food Sensitivity Test (I use the Rocky Mountain Analytical FST in my practice, as well as being the Clinician Support Specialist for the lab) has a long history of being used well in clinical practice to help my patients to understand their sensitivities to foods. If you would like to see our Youtube video presentation, please click here.  If you would like to go directly to references for the Peer-reviewed, published studies which are often said said to not exist, and which validate the testing please scroll to the end of this page.

I want to share some information from the RMA FST factbook, and my colleague Dr Pamela Frank ND has been kind enough to edit the information into this post which I have copied with permission.  Please contact us if you would like more information or click here to book an appointment with Dr Joe.

Dr Joe Klassen, ND

Food Allergies? Food Sensitivities? Food Intolerances? What is the Difference?

By Dr. Pamela Frank, BSc(Hons), ND

Food Allergy Definition

A food allergy is an inappropriate immune system response to a food gauged by the production of antibodies to the food. These are also called Type I immediate hypersensitivity reactions. The most severe food allergies can cause a life-threatening response known as anaphylaxis. Anaphylactic reactions can cause a person’s throat to close, airways to constrict, hives, wheezing, nausea, vomiting, diarrhea, swelling under the skin, and low blood pressure.  These reactions usually involve IgE antibodies to food. Celiac disease, which is a severe gluten allergy, involves IgA and IgG antibodies to gliadin, a protein found in wheat and other cereal grains.

List of the Most Common Food Allergies

The most common triggers of early childhood food allergy are cow’s milk and eggs, which usually cause mild symptoms, limited to the skin (9). Food allergies acquired in infancy typically disappear by early school age.

Other common anaphylactic food allergies are to tree nuts, peanuts, shellfish, soy and wheat.

Food Sensitivity Definition

The term food sensitivity is a non-specific term that is sometimes used to describe milder versions of food allergies or most often, a type III or delayed-sensitivity reaction. These mild food allergies are typically triggered by IgG antibodies to foods and do not cause life-threatening reactions. The release of IgG antibodies to specific foods is considered common, as is the formation of antigen-antibody complexes (which form when a food antigen meets an IgG antibody and they bind together). White blood cells called macrophages typically remove these complexes. However, when many antigen-antibody complexes are present, the capacity of the macrophages to remove them may become overwhelmed. Leftover antigen-antibody complexes can deposit in your tissues and release substances that provoke inflammation. This inflammation is much more prevalent if the reactive food remains a regular part of the diet. Regularly consuming the food perpetuates the production of more immune complexes that may trigger inflammation and contribute to a variety of symptoms.

These types of reactions are also called Type III, delayed hypersensitivity reactions (10) as the onset of symptoms may be 6-12 hours after eating the food or even days later.

List of the Most Common Food Sensitivities

The most common food sensitivities include wheat, gluten, dairy, eggs, almonds, pea, other nuts, legumes, and beans.

Food Intolerance Definition

Food intolerances are foods that a person may have difficulty digesting that result in symptoms such as gas, bloating, abdominal pain and diarrhea. In this instance a person may lack the appropriate enzymes to digest the food, such is the case in lactose intolerance. An enzyme called lactase is required to break down lactose. Lack of this enzyme means that foods containing lactose (dairy products), end up poorly digested in the intestines, where bacteria can ferment the lactose creating bloating, gas and abdominal pain.

List of the Most Common Food Intolerances

Lactose – a sugar found in milk and dairy products

Fructose – a sugar found in fruit

Histamine intolerance – histamine is a chemical compound produced in your body, but that is also present in foods, particularly stored or preserved foods. Some people lack an enzyme known as DAO to effectively break down ingested histamine, leading to dietary histamine intolerance. For someone with a histamine intolerance, ingestion of foods that contain high amounts of histamine can cause inflammatory symptoms such as headaches, flushing, digestive problems, vertigo, congestion and fatigue.

To add to the mix and the confusion, there are also foods and food additives that just don’t agree with people and that can trigger headaches or digestion problems, such as MSG, sulfites, lectins, caffeine, nitrites, aspartame and salicylates.

IgG Food Allergy Symptoms

The symptoms of food sensitivities can include bloating, gas, constipation, diarrhea, abdominal pain, fullness after eating, headaches, migraines, water retention, irritable bowel syndrome, inflammatory bowel disease, and skin conditions like eczema, hives and acne, among other things.

Why Test for IgG Food Sensitivities?

There is much research showing that IgG food reactions are quite relevant in certain disease processes, for example Irritable Bowel Syndrome (1, 18-25), migraines (2), obesity/weight gain (3), atherosclerosis (3), allergies (4,5), eczema (4), urticaria/hives (5), and ulcerative colitis (6). The common underlying mechanism of all of these conditions is inflammation. Removing IgG food sensitivities can help reduce inflammation and may benefit other inflammatory conditions as well. Medical doctors will check for IgG antibodies to a protein called gliadin when assessing a patient for the most severe form of gluten allergy, Celiac disease.

One particular subset of IgG antibodies, IgG4, has been shown to help moderate the immune system, improve immune tolerance and reduce inflammation (8). However, this only applies to this specific IgG antibody (IgG4), not to ALL IgG antibodies.  When testing for food sensitivities, we test for IgG1 – IgG4.  Critics of this test need to get their facts straight and not selectively take from research to support their bias.

How Are IgG Antibodies Detected?

The type of food sensitivity test used in reputable laboratories is called ELISA testing, which stands for enzyme-linked immunosorbent assay. It is a scientifically recognized methodology that was developed in 1978. It is widely used in conventional medical and hospital labs around the world. ELISA testing is used to test for HIV, Celiac disease, Hepatitis B and malaria among many other applications in medical laboratories. Other means of checking for food sensitivities have not been scientifically validated. If a lab claims that their unique patented technology (that is not revealed) is better, do be wary. Lymphocyte analysis for food sensitivities has been shown to be less reproducible than ELISA IgG testing.

Many of those who scoff at IgG food sensitivity testing, have never done it and have never studied it in depth. They have never seen the benefits to people who suffer from rheumatoid arthritis, lupus, asthma, sinus problems, GERD, gallbladder conditions, whole body psoriasis, migraines, irritable bowel syndrome and many other chronic inflammatory conditions. Does a position paper prove that IgG food sensitivity testing is invalid?  It does not! A position paper by definition is only someone’s opinion, again, someone who has likely never had experience with this type of testing. So in this instance, an opinion based on ignorance.

What is the Difference Between Peanut-Type Anaphylactic Food Allergies and IgG-mediated Food Sensitivities?

Severe and potentially life-threatening food allergies are typically caused by IgE antibodies. Your immune system has 5 antibodies in its arsenal as weapons against infectious organisms like viruses and bacteria. Peanut-Type allergies are usually caused by IgE antibodies. Allergists will test for these using a Skin Prick test. This test exposes the person to food allergens like peanuts by pricking the skin with them and watching for a reaction. This is a useful method for detecting IgE antibodies to foods. IgG-mediated food sensitivities are not identified by the Skin Prick test. As IgG antibodies are found primarily in the blood, lymph and intestine. IgG-mediated food sensitivities do not cause life-threatening reactions, but rather “quality of life-threatening” reactions.

If You Eliminate IgG Food Sensitivities, Will You Suffer from Malnutrition? Will it Eliminate Essential Nutrients?

Naturopathic doctors have extensive (4 years after university) training in nutrition. They are well-educated to provide advice on the safe elimination of your food sensitivities. The food IgG sensitivity test is used as a means to identify which foods to eliminate as part of an elimination-challenge diet. This process of food elimination and reintroduction helps to identify which foods are particularly problematic and which foods may be just showing up as a result of frequent exposure to them. Naturopathic doctors can provide nutrition counselling and guidance regarding the replacement of your sensitivities with healthier alternatives for you to ensure a well-rounded diet, nutrient-rich diet. If something that you are eating is inflaming your gut, odds are that you are not adequately absorbing the nutrients that this food purports to provide.

What About Just Doing an Elimination Challenge Diet?

This is also a viable option that we offer to our patients. In some instances, it works well to identify problematic foods. We can provide guidance about what foods to eliminate, for how long, what to use in place of those foods to ensure good nutrition and how to go about reintroducing foods and what to watch for when you do.

In other people, elimination just doesn’t work because there is no “safe” food that may be exempt from causing a reaction, so it’s hard to determine what to eliminate. For example, on food sensitivity testing the following foods have been identified as food triggers in various patients: blueberries, avocado, broccoli, salmon, beef and almonds. In each of these cases, eliminating this offending food has provided relief to the patient of their symptoms. None of these is a food that I would typically recommend avoiding as part of an elimination diet and in fact, most of them are foods that I would encourage people to eat more of. Also, because of the delay in reaction to foods, it may be something that you ate 6-48 hours before that is causing the symptoms you are experiencing right now.

What about Electrodermal testing, Cytotoxic testing and Applied Kinesiology food allergy testing?

I do not recommend these types of unproven means of testing for food  sensitivities. Beware of those who do or those who lump science-based IgG food sensitivity testing in with these methods.

What Should You Do if You Have Food Allergies?

If you have severe anaphylactic allergies, you should avoid those foods entirely until your allergist finds that you no longer test positive and gives you the okay to consume them.  And carry an Epi-Pen or similar protection.

If you have many food sensitivities, it may be that your gut wall is not providing a good barrier between your food and your immune system. Increased intestinal permeability is also referred to in the medical literature as leaky gut syndrome(17). It has been linked to inflammatory bowel diseases like Crohn’s and Ulcerative Colitis (14, 15), but also to mood disorders like Major Depressive Disease (16) and metabolic syndrome (17).

Dr Joe can advise about scientifically proven supplements (11, 12, 13) that help repair your gut and balance your healthy bacteria, along with lifestyle modifications that can also help.

IgG Food Sensitivity Testing & Leaky Gut References

  1. Atkinson W, Sheldon TA, Shaath N, Whorwell PJ. Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial.  2004 Oct;53(10):1459-64.
  2. Alpay K, Ertas M, Orhan EK, Ustay DK, Lieners C, Baykan B. Diet restriction in migraine, based on IgG against foods: a clinical double-blind, randomised, cross-over trial.  2010 Jul;30(7):829-37. doi: 10.1177/0333102410361404. Epub 2010 Mar 10.
  3. Wilders-Truschnig M1, Mangge H, Lieners C, Gruber H, Mayer C, März W. IgG antibodies against food antigens are correlated with inflammation and intima media thickness in obese juveniles. Exp Clin Endocrinol Diabetes. 2008 Apr;116(4):241-5. Epub 2007 Dec 10.
  4. Eysink PE, De Jong MH, Bindels PJ, Scharp-Van Der Linden VT, De Groot CJ, Stapel SO, Aalberse RC. Relation between IgG antibodies to foods and IgE antibodies to milk, egg, cat, dog and/or mite in a cross-sectional study. Clin Exp Allergy. 1999 May;29(5):604-10.
  5. Shakoor Z, AlFaifi A, AlAmro B, AlTawil LN, AlOhaly RY. Prevalence of IgG-mediated food intolerance among patients with allergic symptoms. Ann Saudi Med. 2016 Nov-Dec;36(6):386-390.
  6. Jian L, Anqi H, Gang L, Litian W, Yanyan X, Mengdi W, Tong L. Food Exclusion Based on IgG Antibodies Alleviates Symptoms in Ulcerative Colitis: A Prospective Study. Inflamm Bowel Dis. 2018 May 16. doi: 10.1093/ibd/izy110.
  7. Antibodies: Characteristics and Functions of Immunoglobulin’s (Igs) or Antibodies
  8. van de Veen W, Stanic B, Wirz OF, Jansen K, Globinska A, Akdis M. Role of regulatory B cells in immune tolerance to allergens and beyond. J Allergy Clin Immunol. 2016 Sep;138(3):654-665. doi: 10.1016/j.jaci.2016.07.006.
  9. Grabenhenrich LB. The epidemiology of food allergy in Europe. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz. 2016 Jun;59(6):745-54. doi: 10.1007/s00103-016-2358-z.
  10. Adverse Events Associated with Childhood Vaccines: Evidence Bearing on Causality. Institute of Medicine (US) Vaccine Safety Committee; Stratton KR, Howe CJ, Johnston RB Jr., editors. Washington (DC): National Academies Press (US); 1994.
  11. Musilova S, Rada V, Vlkova E, Bunesova V. Beneficial effects of human milk oligosaccharides on gut microbiota. Benef Microbes. 2014 Sep;5(3):273-83. doi: 10.3920/BM2013.0080.
  12. Kim MH, Kim H. The Roles of Glutamine in the Intestine and Its Implication in Intestinal Diseases. Int J Mol Sci. 2017 May 12;18(5). pii: E1051. doi: 10.3390/ijms18051051.
  13. Davison G, Marchbank T, March DS, Thatcher R, Playford RJ. Zinc carnosine works with bovine colostrum in truncating heavy exercise-induced increase in gut permeability in healthy volunteers. Am J Clin Nutr. 2016 Aug;104(2):526-36. doi: 10.3945/ajcn.116.134403. Epub 2016 Jun 29.
  14. Michielan A, D’Incà R. Intestinal Permeability in Inflammatory Bowel Disease: Pathogenesis, Clinical Evaluation, and Therapy of Leaky Gut. Mediators Inflamm. 2015;2015:628157. doi: 10.1155/2015/628157. Epub 2015 Oct 25.
  15. Bischoff SC, Barbara G, Buurman W, Ockhuizen T, Schulzke JD, Serino M, Tilg H, Watson A, Wells JM. Intestinal permeability–a new target for disease prevention and therapy. BMC Gastroenterol. 2014 Nov 18;14:189. doi: 10.1186/s12876-014-0189-7.
  16. Slyepchenko A, Maes M, Jacka FN, Köhler CA, Barichello T, McIntyre RS, Berk M, Grande I, Foster JA, Vieta E, Carvalho AF. Gut Microbiota, Bacterial Translocation, and Interactions with Diet: Pathophysiological Links between Major Depressive Disorder and Non-Communicable Medical Comorbidities. Psychother Psychosom. 2017;86(1):31-46. Epub 2016 Nov 25.
  17. Fändriks L. Roles of the gut in the metabolic syndrome: an overview.J Intern Med. 2017 Apr;281(4):319-336. doi: 10.1111/joim.12584. Epub 2016 Dec 19.
  18. Atkinson W, Sheldon TA, Shaath N, Whorwell PJ. Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial. Gut 2004; 53: 1459–1464
  19. Zar S, Mincher L, Benson MJ, Kumar D. Food-specific IgG4 antibody-guided exclusion diet improves symptoms and rectal compliance in irritable bowel syndrome. Scand J Gastroenterol 2005; 40: 800–807
  20. Drisko J, Bischoff B, Hall M, McCallum R. Treating irritable bowel syndrome with a food elimination diet followed by food challenge and probiotics. J Am Coll Nutr 2006; 25: 514–522
  21. Zuo XL, Li YQ, Li WJ, et al. Alterations of food antigen-specific serum immunoglobulins G and E antibodies in patients with irritable bowel syndrome and functional dyspepsia. Clin Exp Allergy 2007; 37: 823–830
  22. Yang and Li, Zhonghua Nei Ke Za Zhi. 2007 Aug;46(8):641-3. [The therapeutic effects of eliminating allergic foods according to food-specific IgG antibodies in irritable bowel syndrome].
  23. Ou-Yang et al 2008. Zhongguo Dang Dai Er Ke Za Zhi. 2008 Feb;10(1):21-4. [Application of food allergens specific IgG antibody detection in chronic diarrhea in children].
  24. Fergus S, Peter J. IgG-mediated food intolerance in irritable bowel syndrome: a real phenomenon or an epiphenomenom? Am J Gastroenterol 2005; 100: 1558-9.
  25. Aydinlar EI, et al. IgG-based elimination diet in migraine plus irritable bowel syndrome. Headache 2013;53:514-525.