Published November 9 2015
Food allergies and sensitivities are common with people who have thyroid and autoimmune thyroid conditions. While many people with food allergies and sensitivities have overt symptoms, some people don’t experience any noticeable symptoms. This is especially true with food sensitivities. Of course when someone has a sensitivity to a certain food yet doesn’t experience any symptoms upon eating that food, it can be challenging to determine if they have a sensitivity. And if they continue eating the food they are reacting to it will cause inflammation, which not surprisingly can have a negative effect on their recovery.
I’d like to start by differentiating between a food allergy, sensitivity, and intolerance. Many people use these terms interchangeably, and I’m also guilty of this at times. But there is a difference between an allergy, sensitivity, and an intolerance, and so let’s go ahead and take a look at each of these.
Food allergy. Food allergies are typically referred to as being IgE-mediated. In other words, they involve something called IgE immunoglobulins. Immunoglobulins are also known as antibodies, as they are produced by your immune system and attach to foreign substances, and then your immune system attacks and destroys these substances. IgE is found in the lung, skin, and mucous membranes, and this immunoglobulin is typically involved in immediate allergic reactions.
So for example, if someone is allergic to peanuts and accidentally eats a peanut, and then has a severe allergic reaction within a few seconds or minutes, this is typically an IgE-mediated reaction. It’s a similar situation when someone has an immediate reaction to a bee sting. IgE-mediated reactions occur within two hours of exposure, although in most cases the person reacts much sooner than this. Some of the more common foods which cause allergic reactions include milk, eggs, peanuts, fish, wheat, soy, and tree nuts in children, and peanuts, tree nuts, fish, and shellfish in adults (1) (2). These types of allergies can cause symptoms involving the skin, gastrointestinal tract, respiratory tract, as well as other areas (2). Some of the potential causes of food allergies include a vitamin D deficiency, eating unhealthy dietary fat, obesity, increased hygiene, and the timing of exposure to foods, although genetics and other lifestyle factors can also play a role (3).
Food sensitivity. Whereas food allergies are IgE-mediated, food sensitivities involve immunoglobulin G (IgG). IgG antibodies are found in all body fluids, and they play an important role in fighting bacterial and viral infections. These are involved in delayed-type reactions, and they aren’t always accompanied by overt symptoms. While someone who has an IgE-mediated food allergy will present with symptoms within the first two hours of exposure to the allergen, and frequently within a few seconds or minutes, it can take a few days for someone with an IgG food sensitivity to develop symptoms. And as I have already mentioned, not everyone with a food sensitivity will develop overt symptoms upon exposure to the food they’re sensitive to.
Food intolerance. Unlike food allergies and food sensitivities, food intolerances don’t involve immunoglobulins. They are typically caused by enzymatic defects in the digestive system (i.e. lactose intolerance), although they might also result from pharmacological effects of vasoactive amines present in foods (4). An example of a vasoactive amine is histamine, and when someone has a histamine intolerance this means they have an imbalance between levels of released histamine and the ability of the body to metabolize it (5). Many people have a lactose intolerance, and this is usually caused by a reduction in lactase activity (6). Lactase is the enzyme that breaks down lactose.
How Can You Determine If You Have An Allergy, Sensitivity, or Intolerance?
As I mentioned earlier, a food allergy usually results in immediate symptoms. However, testing is commonly used to detect the presence of these IgE-mediated allergies. Prick skin testing is still used initially by many doctors to determine the presence of an IgE allergy. The way this test works is by introducing a needle into the upper layers of the skin and using a drop of the allergen, and then the release of histamine from mast cells will lead to the development of a wheal greater than 3 mm in diameter if the person is sensitive to the allergen (7) (8). However, there is the possibility of false positive or negative results with this test (9) (10). Serum IgE can also be used in some cases to detect food allergies (11).
Serum IgG testing is commonly used to determine whether someone has a food sensitivity. There are many different companies which offer this type of testing. However, just as is the case with IgE testing for food allergies, IgG testing for food sensitivities has the potential of giving a false result. In fact, it seems that having an increase in intestinal permeability (a leaky gut) will increase the incidence of food sensitivities, and it’s not uncommon for someone with a leaky gut to test positive for many different foods on a food sensitivity panel. I’ll talk about this more later during this article.
One thing you do need to keep in mind is that the food source and purification method used by the company who does the testing is extremely important. As an example, if someone uses IgG testing and tests for apples (which are commonly sprayed with a lot of pesticides), and if the purification method doesn’t do a good job of removing these pesticides, then it’s possible that a positive finding might be due to the pesticide, and not the food allergen itself. In addition, some people might react to a certain food when eaten raw, but not react when eating that same food cooked.
Do I Utilize IgG Food Sensitivity Testing In My Practice?
In the past I haven’t been a big fan of IgG testing for food sensitivities, not only because of the chances of false results, but because such testing is also very expensive. However, when Cyrex Labs recently came out with their Food Immune Reactivity Screen (Array #10) I decided to give it a try, as I not only trust their purification procedures, but they also run everything through twice, which of course increases the accuracy. In addition, they also test numerous foods both raw and cooked. And I have seen some patients test positive for raw foods but negative for cooked foods, and vice versa.
With that being said, I still don’t recommend IgG testing to most of my patients for a few reasons. One reason is that false results are possible. So for example, someone might have a false negative for a certain food on one of these panels, and continue to eat that food. And as a result they will continue to experience inflammation. As I just mentioned, Cyrex Labs does run the test twice to minimize the chance of false results, although a false result is still possible, and of course many other companies don’t run the test more than once. Plus another thing to keep in mind is that no panel tests for everything. So for example, the Array #10 currently doesn’t test for kale, and a few other foods commonly eaten by people following a healthy diet. As a result, if someone is eating kale or any other food that isn’t tested for that they commonly eat, then there is no way of knowing if they have a sensitivity to this food, assuming they don’t experience any overt symptoms when eating it. And while other IgG test panels do test for kale, there are other foods that may not be tested. For example, I recently had a patient do an IgG food sensitivity test on her own that didn’t test for coconut, which is commonly eaten by those following a paleo or autoimmune paleo diet.
Is The ALCAT Accurate and Reproducible?
I’ve worked with a few patients who had ordered the Antigen Leukocyte Cellular Test (ALCAT) through another healthcare practitioner. As mentioned on their website, the ALCAT is a lab based immune stimulation test in which a patient’s white blood cells are challenged with various substances including foods, additives, colorings, chemicals, medicinal herbs, functional foods, molds and pharmaceutical compounds. The patient’s unique set of responses help to identify substances that may trigger potentially harmful immune system reactions”.
So this is different than IgG testing, but is it more accurate? On their website they do list some studies which seem to prove its accuracy. However, I couldn’t find anything on PubMed proving the ALCAT to be accurate or reproducible. Plus, this is also a very expensive test, and although I can offer ALCAT testing to my patients, I choose not to because 1) I’m honestly not sure if it’s an accurate test, and 2) it’s much less expensive to have the patient follow an elimination diet.
How About Mediator Release Testing (MRT)?
MRT is a blood test that measures the changes in circulating white blood cells after it’s exposed to a food antigen. The reason it’s called “mediator release” is because when someone has a negative reaction to a food the white blood cells (i.e. neutrophils, monocytes, eosinophils, etc.) should release inflammatory mediators such as cytokines and histamine. Although the test sounds promising, I don’t think there isn’t sufficient evidence which shows that it is reproducible.
The Enzyme-Linked Immunosorbant Assay/Advanced Cell Test (ELISA/ACT) also tests for delayed food sensitivities. It does this by measuring lymphocytes in a laboratory culture. I don’t have much experience with this test, but one advantage it has over the other tests I have mentioned is that it tests for more foods than most other panels, along with herbs, preservatives, and chemicals. So it is quite comprehensive. But once again, there is not enough evidence which shows that this is accurate or reproducible.
To be fair, even those I’m not a big fan of these tests, I have had some patients obtain either the IgG food sensitivity, ALCAT test, or MRT and feel as if the results of the test were accurate. In other words, they tested positive for certain foods, and felt better upon removing these foods from their diet. But I’ve also come across people who felt like the results weren’t accurate. Even though these are expensive tests, obviously it would be much easier to have people go through a single blood test rather than to follow an elimination diet, and I’m not suggesting that these tests have no value. If someone has been following a natural treatment protocol for a prolonged period of time and they don’t seem to be responding then it might be worth testing for food sensitivities. But in my opinion I don’t think it is necessary to have every single person obtain this type of test.
What’s The Best Method Of Managing Food Allergies and Sensitivities?
If someone tests positive for an IgE-mediated food allergy, then typically the person will need to avoid this food for a prolonged period of time, and sometimes on a permanent basis. Conventional treatment methods are looking at numerous strategies for IgE allergies including sublingual/oral immunotherapy, injection of anti-IgE antibodies, and cytokine/anticytokine therapies (12). Of course one does need to be aware of the potential side effects of these conventional treatment methods.
When someone has a food sensitivity then in most cases they also should avoid the food they’re sensitive to. For example, if someone follows an elimination diet and they have a negative reaction to some foods upon reintroducing them, then they should avoid these foods while trying to restore their health. Similarly, if you are relying on serum IgG testing to determine if you have certain food sensitivities, then you ideally will want to avoid those foods which show up as being positive on this test. However, does this mean that you need to avoid these foods on a permanent basis?
Loss of Oral Tolerance
Many people reading this have heard of Dr. Datis Kharrazian, who is author of the well known book “Why Do I Still Have Thyroid Symptoms When My Lab Tests Are Normal?”. Recently I attended a Thyroid Mastermind meeting, and Dr. Kharrazian was the keynote speaker. One of the topics he discussed had to do with oral tolerance, and he mentioned that when someone has a loss of oral tolerance this will typically result in many sensitivities on a food sensitivity panel. He discussed how this loss of oral tolerance is frequently accompanied by a leaky gut, and how the goal should be to restore oral tolerance, which in turn should allow the person to tolerate most of the foods they were sensitive to.
But how can one restore oral tolerance? According to Dr. Kharrazian, if someone has a leaky gut then this of course needs to be healed. However, he mentioned how it’s not necessary to have a leaky gut in order to have a loss of oral tolerance. In other words, a leaky gut doesn’t directly cause food sensitivities according to Dr. Kharrazian, but it can lead to a loss to oral tolerance, which in turn will cause food sensitivities.
In addition to healing the gut, the person who has lost oral tolerance will need to do things to increase regulatory T cells, give nutrients such as vitamin A and D, and increase glutathione levels. He spoke about how a big problem is with undigested protein, and thus taking digestive enzymes is also very important. He also mentioned the importance of eating plenty of fiber, and actually mentioned a journal article which discussed how short chain fatty acids can help to increase regulatory T cells (13).
One thing that’s important to bring up is that in the past I have spoken to the doctors who work at Cyrex Labs, and they have mentioned that once you test positive for gluten, dairy, corn, yeast, rice, oats, and millet on their Arrays you shouldn’t reintroduce them, as you will always be sensitive to them. I haven’t personally seen any research on this, and so I’m not sure if this is based on their own research, or what they have observed from patients who have tried reintroducing these foods.
If someone has a leaky gut then you might wonder how they can tell when their gut has been healed? Well, the only way to know for certain is through testing, as there are intestinal permeability tests available. The Lactulose/Mannitol test is the classic test for intestinal permeability, and there is also an intestinal permeability test from Cyrex Labs that I have used on my patients. Of course not everyone gets these tests done, as some people begin reintroducing foods once their symptoms have resolved and their blood tests have normalized.
So hopefully you have a better understanding as to the difference between a food allergy, food sensitivity, and food intolerance. A food allergy is IgE-mediated and results in a reaction within two hours of being exposed to the allergen, and frequently within a few seconds or minutes. A food sensitivity is IgG-mediated and involves a delayed response, while most food intolerances are caused by enzymatic defects in their digestive system, although there can be other causes. Testing for food allergies and sensitivities are commonly used by natural healthcare practitioners, although false results are possible. And while avoidance of the food is usually necessary, some people with IgE food allergies are eventually able to consume the allergenic food in the future, while some with IgG food sensitivities are also able to safely eat such foods upon improving oral tolerance and healing the gut.