Diagnostic Tests for Adverse Food Reactions

Before reading this article, it’s probably a good idea to have read my article on food sensitivities and immune reactions. Then take a look at the article below, which is a brief overview of some test options for finding adverse food reactions.

An accurate adverse-food-reaction test is both sensitive and specific. An insensitive test will miss problematic foods; that is, it will give false negatives. A test with poor specificity will identify some foods as problematic, when, in fact, they are not; these are false positives. Also, a test should be reliable; that is, it gives at least 90% consistent results when performing the same test twice on a split sample of blood.

The most accurate food-hypersensitivity test is oral challenge. This is typically done in hospital (due to the risk of anaphylaxis) and is time consuming, tedious, and difficult. The patient eats one and only one food per day. Results are then observed. Over time (a great deal of time!) it becomes clear which foods cause problems and which do not.

The challenge with lab tests for food sensitivities is that there are many (over 100) immune-system mediator chemicals that can lead to illness and discomfort. These mediators include histamine (which causes inflammation and smooth-muscle contraction), cytokines (which can increase or dampen immune reactions), and prostaglandins (which can cause inflammation and pain-receptor activation).

Mediators are found in immune cells and are synthesized in circulation. The list of immune cells is long, and each type of immune cell has a different profile of mediators. Further complicating the diagnostic process is that different hypersensitivity reactions can involve many different immune cells. This means that one can’t assume which cell(s) are involved in the reaction.

Immune mechanisms cause mediator release. Mechanisms include antibodies (IgE, IgG, IgM), complement (C3, C4), and cellular reactions (T-cells).

True allergic reactions primarily involve mast cells, an IgE mechanism, and the release of histamine and other mediators. One test for these IgE reactions is skin testing. Skin pricks/scratches deliver specific antigens (for example, beef, egg, fish, etc) directly into the skin and the swelling/redness response (similar to a mosquito bite) is analyzed. This test is excellent for inhaled allergens (dust, pollen) but poor for food allergens, with about a 40% accuracy. It is useless for food sensitivities, which use a non-IgE pathway of the immune system.

Other food-allergy (not food-sensitivity) tests quantify the amount of IgE present (via RAST or ELISA methodologies). These tests are about 60% accurate for food allergies.

There are some other less-frequently-used food-allergy (IgE) tests known as BHRT and LHRT. These tests compare measurements of histamine in control versus antigen-challenged samples. Like the RAST test, the accuracy is about 60% for food allergies, but the blood sample has a shorter viable life span.

None of the preceding blood tests address food sensitivities (type-3 and -4 immune reactions); the preceding blood tests only address type-1 reactions. Food sensitivity testing presents a puzzle because one must test for reactive foods and chemicals, but the immune responses involve many mediators, cells, and mechanisms.

Some options:

IgG ELISA testing is accurate for measuring IgG but there are several problems. IgG in some cases is a protective antibody, not harmful. The test only measures IgG, which is only involved in some, not all immune reactions. It’s not a useful test for irritable-bowel syndrome (IBS) or migraine, and it can’t test for food chemicals or additives.

ALCAT testing measures changes in white-blood-cell size after antigen exposure. This was a promising test but which has poor split-sample reproducibility and can’t measure lymphocyte (T-cells, NK cells) reactions.

LRA by ELISA/ACT testing had no published studies on reliability or valididty, no support anywhere in medical literature, and the test ignores the importance of granulocytes and mediator release.

Mediator-release test (MRT) measures the changes in ratios of liquids to solids after whole-blood exposure to antigens. This test can’t identify IgE-mediated reactions (true allergic reactions), and it must be done within 32 to 36 hours of taking the blood sample, which is why part of the blood-draw process includes FedEx overnight transport to the lab.

The MRT does offer excellent accuracy for sensitivity reactions (all non-IgE-mediated reactions to food), with a 94.5% sensitivity and a 91.7% specificity. Its reliability of split-sample comparisons is above 90%. It provides endpoint measurements (outcomes of all non-IgE reactions). It can measure both food and chemical reactivity. The test also quantifies the level of reaction, which greatly helps in diet design.

The MRT is the blood test that is the foundation of the LEAP (lifestyle eating and performance) protocol.

It is important to recognize that all food-sensitivity testing (whether optimally valid and reliable or not) provides a limited list of safe foods/chemicals and triggering foods/chemicals. Most persons tend to view the results as a list of foods  to avoid — end of story. However, that is not the end of the story. Because there are thousands of foods and food chemicals that we might consume, any sensitivity test is just a window to that universe. So these tests provide not only a foods-to-be-avoided list, but also a safe-foods list. It is the latter, the safe-foods list, that the dietitian and client use as a starting point in a process to eventually introduce non-tested foods and evaluate for sensitivities to those.

Food Sensitivities and Immune Reactions

In concise terms, food sensitivities are type-3 and type-4 immune reactions to certain foods. Some people speak of food sensitivities as being in the general category of food allergies, but most allergists would not agree with this label. True food allergies are usually a type-I immune response — a response that can sometimes be life threatening such as, for example, with some person’s peanut allergies, which can trigger anaphylactic shock.

Also, food sensitivities are not the same as food intolerances. Food intolerances usually indicate the inability to digest a given food. A common example of this would be lactose intolerance, which is caused by a person being deficient in the digestive enzyme lactase. Food intolerances generally don’t involve the immune system.

Before I can go further, I should explain more about the basic process of the immune system.

From a high-level view, here are the steps of an immune response:

  1. An external stimulus triggers the immune system; that is, the immune system identifies some substance as “foreign” and requiring a defensive reactions.
  2. Then the immune system releases chemicals called mediators. There are many mediators including histamine, cytokines, prostaglandins, and more — there are roughly 100 different mediators. There are various mechanisms that cause mediator release. Humoral mechanisms release antibodies (such as IgE, IgG and IgM — and these antibodies such as IgE then trigger the release of mediators) and compliment (C3 and C4). Cellular mechanisms trigger cellular reactions (T-cells, phagocytes, granulocytes and NK cells).
    There are also non-immune processes that deliver mediators within the body including eating foods containing lectins and histamine.
  3. Mediators then trigger the actual immune defense process, AND, most importantly, mediators can, in some persons, trigger the symptoms that we perceive as clinical illness.

Mediators are found in white-blood cells (WBC) and in circulation, but are primarily from WBC. Different types of WBC include mast cells, basophils, eosinophils, macrophages, monocytes, neutrophils, NK cells (natural-killer cells), and T cells.

Immune-system reactions are also classified by type. Type-1 reactions are IgE mediated (or, more accurately, have an IgE mechanism that causes mediator release). These are true allergic reactions and are the main type of immune response addressed by allergists. There are common tests to determine IgE reactivity. The skin-prick or skin-scratch tests are best to determine environmental allergens, but are not as accurate for finding food allergens. The best way to find food allergens is via a blood test. These tests are commonly performed by physicians.

Type-3 and type-4 immune reactions pertain to food sensitivity.

Type-3 reactions rely on antigen-antibody complexes that activate compliment, which in turn attracts neutrophils that degranulate and release tissue-damaging enzymes. Complexes present in too large a quantity to be appropriately cleared by the innate immune system attract leukocytes, which then can release mediators that create an inflammatory response that underlies many so-called immune-complex diseases including lupus, rheumatoid arthritis, and reactive arthritis.

Type-4 reactions are cell mediated, not involving antibodies — only T-cells and granulocytes. Irritable-bowel syndrome (IBS) and migraine headaches are most commonly type-4 reactions.

The following chart summarizes the immune-type reactions involved in food allergies (type 1) and food sensitivities (types 3 and 4):

Type 1 Type 3 Type 4
Cells Involved In Mediator Release Mast Cells
NK cells
NK cells
T Cells
Involved In Mediator Release
T-Cell Mediated

In  my work with clients, we focus on finding and eliminating foods that trigger type-3 and -4 reactions, and, most importantly, foods that don’t trigger immune reactions. We use the mediator-release blood test (MRT) as the STARTING point for the LEAP protocol, which initially puts the client on a non-triggering diet to allow the immune process to quiet and calm. Then as the protocol progresses, new foods are added in a very controlled, structured way to identify foods that are triggering counter-productive immune responses, and then eliminate those triggering foods from the clients diet.




What is a LEAP Therapist?

LEAP is an acronym, which stands for lifestyle eating and performance.  The LEAP process is based on the following essential concepts:

  • An understanding that many physical conditions such as irritable bowel syndrome, migraine headaches, fibromyalgia, and others are caused by an inappropriate immune-system reaction to food (food sensitivities)
  • A recognition that, even once a person figures out that they may have food sensitivities causing real physical problems, it is often difficult to sort out which foods are causing problems and which are safe to eat
  • There is a blood test available that can determine, from a list of 150 common foods and food chemicals, which are safest and least likely to cause a reaction in the food-sensitive person.
  • From that initial starting point, a trained health-care professional, a certified LEAP therapist (CLT), works with the client to build an initially-restricted diet that is most non-reactive — that is, one that will likely cause food-reaction symptoms to diminish.
  • After the initial diet shows success, other foods are added to the diet one new item per day according to a proven, logical protocol.
  • The LEAP client follows the dietary protocol and records foods eaten and any reactions that occur.
  • The LEAP client is responsible for following the program and taking charge of his or her lifestyle choices to optimize health — using the advice and counsel of the supporting health-care team, especially the CLT.
  • The CLT is a health-care professional — usually a university-and-hospital-trained registered dietitian-nutritionist (designated as RD or RDN), but occasionally a registered nurse or physician — who has received additional training and certification in the proper use of the blood test, the mediator-release test (MRT), and the accompanying dietary protocol.

A certified LEAP therapist has undergone significant additional training to be certified to recommend and interpret the results of the MRT, and then to work with the food-sensitive client to follow the protocol to optimize dietary and other lifestyle choices.

The MRT alone is not the solution. It is the starting point. Sometimes the MRT will show that a given food is likely to be safe, yet because of the client’s reactivity to certain food chemicals, the CLT will recommend the food’s elimination from the client’s diet initially anyway. Reliance on the knowledge and experience of the CLT is important for the success of the LEAP process.

Also, from a very practical perspective, there may be 10,000 foods from which a person can choose. But the best food-sensitivity test, the MRT, only tests a maximum of 150 items. It is the MRT plus the LEAP process that provides the most successful outcomes.

If you suspect that it is your food that is giving you significant health issues, contact a certified LEAP therapist and explore the LEAP process. It may be the path to a happier, healthier future for you.

US Research Verifying What European Researchers Have Known….

A recent article in USA Today, entitled Study finds non-celiac gluten sensitivity is not imagined, is proclaiming old news for those of us who specialize in treating conditions due to food sensitivity.

Yawn. This is no shocker if one has been paying attention to world-wide research for the past 25 years or more. And it has not just been limited to non-celiac gluten sensitivity.

While it is true that in some people, gluten triggers an immune reaction that is systemic and can have far-reaching consequences, this recent research out of Columbia University merely confirms a small portion of what has been shown in work largely done outside the United States. We actually know from both the scientific research and enormous volumes of treatment outcomes that not only can gluten be a trigger for inappropriate immune response, but any number of other foods and food chemicals can also cause wide-ranging problems.

Published research has documented illnesses due to food-stimulated immune response that includes the following: irritable-bowel syndrome (diarrhea, constipation or both combined), migraine and other headaches, fibromyalgia, and more. But through 1996, this aspect of immunological research was primarily investigated in Europe, not the USA.

Yet some physicians to this day question the link between food sensitivity and illness. This despite the fact that, supporting the idea that immune reactions to food underlies or contributes to various medical conditions, many research articles have been published in journals and books such as Headache, Pediatric Neurology, Lancet, Current Opinion in Immunology, Allergy, Cephalalgia, Journal of the Royal Society of Medicine, Medical Hypotheses, Acta Neurologica Scandinavica, Journal of Pediatrics, Annals of Allergy, Recenti Progressi in Medicina, Journal of Neurology Neurosurgery and Psychiatry, Food Allergy and Food Intolerance, 2nd Ed, Pediatric Review, American Clinical Laboratory, Gastroenterology, Canadian Journal of Gastroenterology, Current Opinion in Immunology, Gut, Bailliere’s Clinical Gastroenterology, Digestive Disease Week, and more.

Even the growing number of doctors who understand and accept that in some people food causes illness — even wholistic doctors — are typically neither trained nor have the clinical tools at hand to do any more than make food-elimination suggestions that amount to shooting in the dark.

It is largely a subset of registered-dietitian nutritionists who have access to the most accurate and helpful blood test as well as the time, training, and protocol to follow through and most fully resolve the link between food sensitivity and illness.

Also, be aware that there is no such thing as universally-appropriate diets to treat food-sensitivity problems including IBS diets, migraine diets, fibromyalgia diets, etc. Every individual is unique and requires a customized approach.