These days we are encountered with an epidemic of chronic health issues resulting from inflammation, which is most often rooted in the gut. By understanding the gut in more detail, we have the capacity to decrease inflammation without the use of medications that have long lists of side effects and don’t solve the underlying issue.
The important thing to realize about this inflammation is that it can appear in any part of the body, including hormone systems, the brain and the cardiovascular system. The evidence for this is unquestionable. This being said, it is very important to identify foods which may be stimulating our immune system and having detrimental downstream health effects.
Food sensitivity testing has its controversies, but it can be a very useful starting point. IgG testing is best researched in IBS and Crohn’s disease, but is clinically applicable in many other illnesses. The tests are indicated in any gut complaints, chronic fatigue, depression and anxiety and autoimmune issues, to name a few.
Limitations of food sensitivity testing:
1. They test only limited immune reactions and do not show non-immune food reactions
Food sensitivity testing is not perfect, as it is only testing a very select part of the immune system. The most common parts of the immune system that are tested are IgE (true allergy), IgA (mucosal immune system) or IgG (delayed food sensitivities). A negative test does not exclude a reaction by the innate immune system, or a non-immune reaction (like lactose intolerance, FODMAP intolerance, or histamine intolerance).
2. Laboratory standards differ
The accuracy of testing can vary from lab to lab, depending on which controls and which antigens they use. For example, an organic apple may have different reactivity to one that is not organic. Heat and processing or roasting may make an antigen more or less antigenic. Whether the lab uses monoclonal antibodies (from one source) vs polyclonal antibodies (from many sources), can also affect the reactivity of the test.
3. Individual and confounding factors
False positives may result from smoking, alcohol consumption, periodontal disease and other factors. False negatives may result from immunoglobulin deficiencies. Individual differences in immunoglobulins may not be picked up by lab testing, which could also skew results.
Testing often shows reaction to antigens which should be ‘healthy’ foods. This situation is often caused by increased intestinal permeability. Something like gluten may trigger leaky gut, allowing bystanders to leak through the gut layer and stimulate an immune reaction. Gut repair is essential in resolving this.
With all these confounding factors, how do you figure out what you are reacting to?
The gold standard of figuring of food sensitivities is with an elimination diet. This means taking out the common allergenic offending foods for a period of 3-4 weeks minimum, and then slowly reintroducing them one by one. A positive test results when a reaction to the reintroduced food occurs.
In an ideal world, every patient with a chronic health condition should go through an elimination diet. In reality, this does not happen. In many cases, people do not believe that their health condition is related to food and so are not willing to change their way of eating.
The benefits of food sensitivity testing:
Enter the food sensitivity test. Though not all testing is perfect, this can be an extremely useful tool in figuring out major food triggers. Keeping the above limitations in mind, improvements in symptoms should occur with removal of the offending foods. The proof is in the pudding: people very often do get dramatically better when they remove the positive foods on the tests.
When they do not get better after a trial of elimination, a skilled health care professional will guide the patient to work through different steps based on their history, physical examination and testing, to figure out what is causing their symptoms.
There are many reasons people don’t get better:
1. Gut healing was not done alongside removing the problem foods. Much research has been done around removal of gluten with and without gut repair. A large percentage of patients do not improve symptomatically when gut repair is not undertaken. This involves replacing pancreatic enzymes, gallbladder support and stomach acid and healing the lining of the gut.
2. The person is reacting to food in a different way. They may have a histamine, salicylate or oxalate intolerance. They may have a lectin intolerance and respond to a grain and legume free diet. They could also have a fructose intolerance.
3. They may have dysbiosis, or overgrowth of bacteria/ yeast or parasites (often interrelated with food sensitivities). Because of this they may have FODMAP intolerance (with SIBO) or may react to foods that trigger candida, like sugar.
4. They have a misunderstanding of which foods contain the antigens they are reacting to, or are being inadvertently exposed. A common example is gluten, which is found in many spices, teas, toothpaste etc.
5. Their symptoms may not be directly related to the gut and can be related to heavy metal toxicity, biotoxin illness (mold commonly causes gut issues) or autonomic imbalance.
6. They had a false positive test.
The good news
The aim is not to be off the offending food forever - the aim is to figure out why someone is reacting in the first place. If gut healing and elimination is done correctly, the person should be able to eat most things again. Some people may need to stay off certain foods lifelong - gluten, dairy and eggs are the most common of these.
The bottom line is that food sensitivity testing is far from perfect, but it is very often a starting point to guide a patient in the right direction and motivate lifestyle changes. The important take home is to ask why the food reactions are happening in the first place. On many occasions, people become frustrated because they follow the elimination of the foods found on their tests and they don’t feel better. It is essential to have an experienced health care provider interpret your food sensitivity test in the context of what your issues are so that you can be guided in the right direction and achieve the best results.
Dr. Michelle van der Westhuizen
1. “Treating Irritable Bowel” by Drisko, et al Journal of American Nutrition Vol. 25 #6 514-522 Pub. 2006
2.“Delayed Onset Food Allergies” by Melletis, C. and Barker, J. Alternative and Complementary Therapies, Pg. 61-65 April 2003
3. The value of eliminating foods according to food-specific immunoglobulin G antibodies in irritable bowel syndrome with diarrhoea. Guo H, Jiang T, Wang J, Chang Y, Guo H, Zhang W.
4. Food-specific IgG4 antibody-guided exclusion diet improves symptoms and rectal compliance in irritable bowel syndrome. Zar S, Mincher L, Benson MJ, Kumar D.
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