Food allergies, sensitivities, and intolerances – What is the difference? And what to do about them
Adverse reactions to foods including food allergies, sensitivities, and intolerances are on the rise, becoming more of a health concern for many. While true food allergies are certainly on the rise, there are many people who don’t have food allergies who are still experiencing adverse food reactions. It is important not to misinterpret a negative food allergy test result to mean the foods you eat are not provoking symptoms. Sometimes a patient will tell me “I thought I was reacting to foods but when I was tested they found I don’t have food allergies, so that’s not the problem.” When you understand the many different types of food reactions that can take place, including food allergies, sensitivities, and intolerances, diet can be properly addressed in order to achieve relief from symptoms and a return to wellness.
Food reactions, including food allergies, sensitivities, and intolerances, can be separated into 2 main categories: those mediated by the immune system, and those which are not. Reactions that are immune-mediated include food allergies, food sensitivities, and auto-immune food reactions. Reactions that are not immune-mediated are referred to as intolerances. A food intolerance results from the deficiency in an enzyme needed to digest a certain component of a food.
Immune-mediated Adverse Food reactions
Food sensitivities are characterized by symptoms that can be delayed, dose-related, and resulting from a combined effect of multiple foods. Symptoms associated with food sensitivity include diarrhea, bloating, gas, abdominal pain, headache, fatigue, migraine, brain fog, edema, excess mucous production, muscle or joint pain, malaise, and others. There are many medical conditions associated with food sensitivity, including irritable bowel syndrome (IBS), fibromyalgia, migraine, chronic fatigue, arthritis, and others.
Food sensitivities can be difficult to identify due to the subtle, chronic, and insidious nature of their reactions. For many years the standard of care has been to conduct an elimination diet which involves the elimination of most foods followed by oral challenge, using a food diary to help identify problematic foods. I still believe an elimination diet is the best method to use, because there is no one test that will identify every type of food reaction, nor is there a test that can possibly test for all the different foods and food chemicals you may be exposed to with a typical diet. However, we are extremely fortunate to have the benefit of food sensitivity testing to help guide an elimination diet, and the use of testing is invaluable in developing a much more effective diet protocol that does not involve severe dietary restriction. The days of the lamb, rice, and pear elimination diets in comparison to using a good food sensitivity test appear barbaric in comparison (not to mention I have seen many patients test reactive to lamb, rice, and pears.) I will discuss food sensitivity testing and elimination diets more later in this article.
Food allergies involve IgE antibodies which result in histamine release. Generally, food allergy symptoms are more immediate and noticeable than foods sensitivities, and often are easier to trace back to the offending food. Symptoms of food allergy include itching or swelling of the skin, eczema, itching or swelling of the tongue, lips, or mouth, difficulty breathing, nasal congestion, abdominal pain, nausea, or vomiting. Although the tests available for food allergies vary in their accuracy, a food allergy test can be a helpful tool in tough cases where offending foods are difficult to identify.
Auto-immune food reactions
Auto-immune disease occurs when the body’s immune system attacks its own cells. The most well-researched auto-immune food reaction is the role gluten plays in celiac disease. In the case of celiac disease, gluten, which is a protein in wheat, triggers the auto-immune response which results in damage to the villi in the intestines. Eliminating gluten completely from the diet is the only known treatment for this condition. Gluten is suspected in playing a role in other auto-immune conditions such as Hashimoto’s, although this is not as well-established or as widely accepted.
Non-Immune-mediated Adverse Food reactions
The most common and well-known type of food intolerance is lactose intolerance. The lactase enzyme is necessary to digest lactose, the sugar found in cow’s milk. When lactase is absent or present in insufficient quantities, the lactose consumed is instead digested by bacteria in the gut. This results in the production of gas and/or lactic acid which causes bloating, abdominal discomfort, loose stools, or diarrhea. Lactose intolerance can be tested for using a breath test, although many people are able to determine they are intolerant without the use of testing. By avoiding lactose-containing foods, or taking a lactase enzyme supplement when dairy is consumed, symptoms of lactose intolerance can be managed and eliminated. Other food intolerances include fructose intolerance, bile salt deficiency, and FODMAP intolerance. While in many cases food intolerances are irreversible, it is my experience that symptoms can be managed and in some cases, tolerance can return once the cause of the intolerance is properly addressed.
The use of testing and elimination diet to identify food allergies, sensitivities, and intolerances
Identifying and eliminating food allergies, sensitivities, and intolerances is no longer the treacherous task it used to be. With the use of quality testing, elimination diet, and food records patients can navigate their way to a state of wellness that many have come to believe they could never achieve again. Because of the delayed, dose-dependent, and combined nature of food sensitivity reactions, these can be the most difficult to identify without testing. For this reason, I prefer to conduct a LEAP diet, which combines the use of a highly accurate food sensitivity test call the Mediator Release Test (MRT), with a very specific elimination protocol that yields fantastic results when done properly. This protocol helps identify all 3 adverse food reactions discussed here: food allergies, sensitivities, and intolerances.
Often patients who are still suffering greatly will visit me and say they’ve already had food sensitivity testing done with minimal results. This does not surprise me at all, because the utility of some of the food sensitivity tests that are still widely used is very poor. Because food sensitivity tests vary greatly, I would like to explain a little more about the mechanism in which food sensitivities occur to demonstrate why some tests are a waste of time.
The first, and most commonly used type of food sensitivity test is the IgG ELISA test. IgG is an antibody of the immune system that can be activated in response to a perceived threat. This can result in the release of mediators which wreak havoc on the invader and surrounding tissues. It is the mediators, not the IgG itself, that are the direct cause of inflammation and symptoms. Examples of mediators include histamine, cytokines, and prostaglandins. There are about 100 different kinds of mediators. To further complicate things, IgG is not the only branch of the immune system called upon in these reactions. IgM and IgA are examples of other antibodies that can also be involved, as well as complement, and cell to cell reactions that do not involve antibodies at all.
You can see, therefore, why testing the increase in IgG levels when blood is exposed to a food is minimally useful because it is only capturing a small portion of degree of reaction, not to mention that IgG release can occur as a protective response or simply as an indication of exposure to a food, and therefore its presence does not always indicate there is any mediator release taking place at all. A 2008 article in the journal Allergy states “Testing of IgG to foods is considered irrelevant for the laboratory work-up of food allergy and intolerance and should not be performed in case of food-related complaints.”
Because of this, I prefer to use an end-point test which simply measures the volume of mediator release to give an accurate representation of to what degree various foods provoke symptoms. The most accurate test available for this is the MRT, which is performed by Oxford Biomedical Technologies, and I am continually amazed at the astounding improvement my patients achieve when this test is used to guide their dietary protocol (the LEAP diet). I do not recommend the ALCAT test because although it is also an end-point test, the test has very low split-sample reproducibility (60% according to an article published in Natural Medicine Journal). The MRT, in comparison, has a sensitivity, specificity, and reliability above 90%.
Because IgE is involved in all allergic reactions, food allergy tests that measure IgE response when blood or skin is exposed to a particular food are considered a valid way to measure for food allergy. Skin prick testing involves introducing the skin to the potential allergen and measuring the wheal response that results on the skin. While this method of testing is very good for inhalant allergies, it is not as accurate when testing for food allergies. Another test, IgE RAST or ELISA testing is a bit more accurate than skin prick testing. I find however, that although the use of food allergy testing can complement the LEAP protocol, it is not necessary in most cases as the elimination diet helps any unidentified food allergies that may be present come to light.
If you or someone you love is suffering chronic symptoms related to food allergies, sensitivities, and intolerances, you don’t have to continue allowing those symptoms to claim more and more of your quality of life. I’m constantly amazed that something as simple as dietary modification can be the answer in restoring a normal life for so many patients. Please call (602) 422-9800 today or email firstname.lastname@example.org to schedule an initial consultation to find out if food allergies, sensitivities, and intolerances may be the missing piece of the puzzle for you. You may also click here to request a consult, or sign up here for free email tips. Healthy regards!