Lab Notes

Understanding food allergy, food sensitivity and the Alcat Test

by Dr. Patricia Shelton, MD, RYT

For centuries, most people ate whatever everyone around them was eating. If everyone else ate bread, they also ate bread; few people attempted to alter their diets in order to solve health problems. In the past few decades, the idea of altering the diet in order to create the conditions for optimal health began to enter the mainstream. One early change was the emergence of low-fat foods; many people began to avoid foods with high levels of saturated fat, or to consume low-fat versions of their favorite foods. (Many are now questioning whether low-fat was the right choice, but at least people were thinking about the relationship of health to diet.) Organic foods became more and more popular through the next few decades, as people began to recognize the impact of conventionally used chemicals such as pesticides on human health. The idea that what we eat has a huge impact on our health began to be widely accepted.

More recently, the idea of personalizing the diet to avoid foods that create inflammation has been entering the mainstream. Some physicians, nutritionists and other health practitioners advocate the avoidance of all commonly allergenic foods by virtually everyone; wheat, dairy (cow’s milk), soy, peanuts, and eggs are among those most commonly selected for avoidance. However, there is a cost to avoiding particular foods in the diet; it may become difficult to obtain necessary nutrients if too many foods are avoided, and eating a variety of foods is widely recognized as a health-promoting practice. Additionally, some people may be reactive to foods other than those on the “most-common” list. Therefore, many people seek to find out which foods they are reactive to, so that they can avoid those foods without overly restricting the diet. Although some people attempt to accomplish this through eliminating large numbers of foods and then re-introducing them while monitoring for symptoms, this can be unwieldy given that we eat hundreds of foods.

Inflammation and Chronic Disease

Chronic diseases, such as heart disease, cancer, and diabetes, are by far the leading cause of death and disability among the populations of developed countries. While these were not traditionally thought to be inflammatory diseases, much recent research has focused on the role of inflammation in these diseases. For example, many studies have linked increases in the biomarkers of inflammation to the risk of heart attack and stroke, to an increased risk of developing cancer, and to a poorer prognosis in those who have been diagnosed with cancer. This has been done in many different types of cancer, including prostate, colorectal, and breast cancers.

The scientific literature that links inflammation to the chronic diseases most feared by the people of developed countries is large and growing. Because of this, many people would like to reduce the levels of inflammation in their bodies. Some common issues include irritable bowel syndrome (IBS) and other digestive symptoms, skin conditions such as eczema and urticaria (hives), migraine headaches, and chronic fatigue, though there are many others. These, too, often have an inflammatory component, and so people who have these conditions would do well to reduce the levels of inflammation in their bodies. But given that there are a huge number of substances to which we are exposed daily, it can be overwhelming to decide where to start. Well, there’s one thing we put directly into our bodies multiple times per day: food.

Understanding Food-Mediated Inflammation

When it comes to understanding the impact of various foods on the immune system, it’s easy to get confused by the scientific terminology. Before looking at what the Alcat test actually measures, it would be helpful to start with a basic look at this field.

The immune system’s main component is the white blood cells (WBCs, also known as leukocytes). They spend much of their time circulating in the blood, searching for and destroying foreign invaders such as bacteria. There are a number of different types of leukocytes, each specialized for a particular function; they work together, like the instruments in a symphony. The immune system has two main arms: the adaptive immune system, which “remembers” previously encountered antigens (foreign proteins) to mount an effective response, and the innate immune system, which is present at birth and is less discriminating with respect to what it attacks.

The adaptive immune system consists of the leukocytes called lymphocytes, of which there are several types. One of the types of lymphocytes produces a group of proteins called immunoglobulins (“Ig”s), also known as antibodies, and others respond to antibodies that have bound to the protein they recognize. While only a small percentage of leukocytes are lymphocytes, these cells are extremely important to the immune system, as they allow the targeted destruction of particular invaders and possess the capacity to “remember” previously encountered proteins in order to mount a quick and effective defense. Vaccines work by stimulating the adaptive immune system, while the HIV virus causes AIDS by destroying lymphocytes. In some people, the adaptive immune system becomes inappropriately sensitized to the patient’s own tissues; this is called autoimmunity, and leads to a variety of diseases.

The other arm of the immune system is the innate immune system. The cells of this arm of the immune system are far more numerous, and as a group are called granulocytes. A subtype of granulocytes known as neutrophils constitute well over half of the total leukocytes in the immune system. They perform the functions of cleaning up cellular debris and waste, and destroying invaders. When neutrophils are activated, they secrete a number of extremely toxic substances, in order to kill whatever type of invader they have encountered. These substances are thought to be a major reason that inflammation causes chronic disease. They are toxic not only to bacterial cells, but to human cells as well; when secreted in large amounts, they can lead to symptoms as well as to chronic diseases.

The term “food allergy” refers to the production of immunoglobulins in response to the consumption of particular foods. One commonly used test for food allergies measures the levels of antibodies in the blood that respond to potential food allergens. The patient’s blood is exposed to hundreds of different food proteins, and the test looks for binding of the patient’s immunoglobulins to these proteins. If the patient has antibodies against a food, it indicates that the immune system is treating that food as though it were an invading microbe, and is attacking it as such. A patient who has a food allergy will generally “feel sick” soon after consuming the allergenic food. Sometimes, the food allergy is so severe that the patient’s airway can become blocked by the inflammation triggered by the food; for most patients, consumption of the food is not fatal, but does cause unpleasant symptoms that may affect the patient’s quality of life.

For some people, eating a particular food leads to dysfunction in the body, but does not directly lead to the secretion of immunoglobulins; rather, the inflammation occurs through the innate immune system. In this case, rather than a food allergy, the patient would be said to have a “food intolerance.” Food intolerance can be much more difficult to diagnose than food allergy, in part because the patient may not experience symptoms soon after consuming the food, but rather hours or days later. When the patient’s blood is exposed to allergens, no binding of immunoglobulins would be detected, and so traditional food allergy tests do not detect food intolerance. Instead, it’s necessary to look for other markers of immune system activation in order to detect food intolerance in the laboratory.

The Alcat Test

The Alcat test is a blood test that was developed in order to look for food intolerance. This test looks at the entire population of leukocytes present in the blood. Recall that only a small percentage of leukocytes are lymphocytes that produce antibodies; a typical food allergy test would look only at this small population of cells. The Alcat test, however, includes all of the patient’s leukocytes.

When a neutrophil (or other granulocyte) encounters an antigen that activates it, it releases the toxic substances it has stored inside its granules. As these are released, the cell changes size, becoming significantly smaller. Sometimes, the cell is lysed (broken open) by this event. (Pus or thick mucus is made up primarily of neutrophils that have completed their mission and then died.) The Alcat test compares the size and number of leukocytes present in the patient’s blood at baseline with the size and number of leukocytes after the blood has been exposed to a particular antigen. If the antigen caused a significant degree of activation of leukocytes, there will be detectable decreases in the number of cells and the average size of each cell. The test classifies each antigen as “non-reactive,” meaning that no change in these measurements was detected; “reactive,” meaning that a large change was detected; or “borderline,” meaning that a small change was detected. This classification can then be used by the patient in deciding which foods to consume. The recommendation is to consume only non-reactive foods for a period of time, rotating in the borderline foods; eventually, the patient can try gradually re-introducing reactive foods, as the immune system may no longer be sensitive to these foods after a period of “rest” from them. Some foods may need to be avoided permanently.

Understanding the science behind the Alcat test is useful. However, what you really want to know is whether the Alcat test can help you heal from your chronic ailments. There have been several scientific studies of the Alcat test that indicate its potential utility in helping a patient heal disease through the avoidance of foods causing inflammation.

Two studies conducted in the United Kingdom in the 1980s indicated that the Alcat test could be useful to patients in real-world situations. In both of these studies, patients were recruited who had chronic health conditions that hadn’t been adequately treated by conventional medicine. They recorded their symptoms at baseline, and then received an Alcat test. For two weeks, they completely avoided any food to which they reacted on the test. Then, for the next six weeks, test foods were rotated into the diet; some were foods that the patients had been reactive to, and others were foods to which patients had been non-reactive. This was a placebo-controlled study, meaning that neither the patients nor their doctors were aware of whether the foods being added to the diet were reactive or non-reactive on the patient’s Alcat.

Some of the patients dropped out of the study because they simply could not tolerate bringing particular foods back into the diet; their symptoms were too bad. 90% of such patients had reacted on the Alcat to the food they couldn’t tolerate. Of those who remained in the study, a majority had improvement in their symptoms when they followed the diet indicated by the Alcat. Symptoms as diverse as migraine, eczema, and hay fever were each improved by 70% or more. There was a significant correlation between the foods to which patients were reactive on the test, and the foods that worsened their symptoms when consumed (over 80%; given the number of factors in a person’s life that could affect symptoms, such as stress, exercise, sleep, and others, a 100% correlation would not be expected).

Studies following this one and continuing up to the present day have indicated that many patients experience improvements in their symptoms by using the results of the Alcat to choose their diets. Over half of patients with irritable bowel syndrome (IBS) experienced improvement; given that conventional medicine has very little to offer these patients, this is a significant number. Other studies have shown significant improvements in migraine, skin conditions such as eczema, gastrointestinal conditions, allergic rhinitis (hay fever), chronic fatigue. In these studies, at least 50% of patients reported improvement in their health conditions after following the Alcat-recommended diet.

Currently, Yale School of Medicine is conducting research to further understanding of the complex pathways underlying the Alcat Test.