What are Food Allergies?
What are food allergies? This is a difficult question with confusing answers (possibly because some doctors use semantics to trivialize a problem they have trouble dealing with). When the term “allergy” was first coined, it meant an adverse reaction to any substance that does not bother most people. Then in the 1920’s, it was discovered that a type of antibody called “Reagin” or IgE was involved in many allergic reactions, especially those to inhalants. So conventional medicine defined allergy as an IgE-mediated response.
IgE-mediated allergies are easily detected by standard blood or skin tests. The reactions happen rapidly, usually within a few minutes of exposure to inhaled substances or eating a food. Small amounts of the offending substance trigger the reactions, which commonly occur in the respiratory tract, digestive system, or skin. IgE-mediated food reactions are often “fixed.” This means that after months or years of avoiding a problem food, eating any amount of it will still cause symptoms.
Many adverse reactions to foods do not involve IgE antibodies. They are often called food “sensitivities” or “intolerances.” The absence of IgE does not make them any less real; other immune mechanisms, such as IgG antibodies, immune complexes, or cell mediated reactions are involved instead. These reactions can happen quickly or can be delayed for two to seventy-two hours or longer. This makes home challenge testing for them much more difficult.
On this website the word “allergy” will be used in its original sense. Any immune-system related adverse reaction to a food will be called a food allergy without debate about the immune mechanism involved. Indeed, many adverse reactions can involve more than one mechanism.
Over seventy medical conditions are thought to be associated with food allergies. These conditions can be respiratory (hayfever, asthma, bronchitis, recurring ear infections, sinus conditions, rhinitis, laryngitis, allergic sore throat, hoarseness); digestive (gastroenteritis, irritable bowel syndrome, celiac disease, inflammatory bowel disease, diarrhea, constipation, colic, malabsorption); cerebral (headaches, dizziness, sleep disorders, learning disorders, tension-fatigue syndrome, foggy thinking, irritability, depression); skin-related (dermatitis, eczema, angioedema, hives, rashes); or related to other body systems (arthritis, myalgia, urinary irritation, conjunctivitis, edema, hypoglycemia, diabetes, overweight, underweight, premenstrual syndrome, fatigue).{1} This list is not exhaustive. Virtually any symptom can be associated with food allergy or intolerance. By identifying and eliminating or treating food allergies, many of our seemingly insolvable chronic health problems can be improved or eradicated.
“Why do we have food allergies?” is also a difficult question. When my food allergies were first diagnosed, I asked the doctor, “Why did I suddenly develop all of these food allergies?”
His reply was, “You may have had them for a long time without realizing it.” His answer may have been partially correct, because I was always an allergic person from a family of allergic people, but he did not consider what had suddenly caused a change in the level of my allergies. It is only by addressing the “whys” of our food allergies that we can hope to actually solve the problem.
Heredity is often cited as a cause of food allergies, and certainly plays a role since a recessive gene has been identified as being linked to IgE-mediated food allergies.{2} Repeated exposure to the same foods, especially in large quantities, is also implicated. {3}Yet other factors also contribute to the severity and number of allergies most allergy prone people endure.
The most common cause of multiple food allergies, in my opinion, is having a
“leaky gut,” or increased intestinal permeability. (This can be debated as a “chicken or egg” story though; which came first, the increased intestinal permeability or the food allergies?) Small openings can occur in the lining of the intestine, which allow large molecules of undigested or incompletely digested food to enter the bloodstream. If the quantity is too great for the liver to “clear” almost immediately, the immune system has a chance to recognize these molecules as being foreign to the body and produces antibodies against them. When the food is eaten again and again passes into the bloodstream undigested or only partially digested, the antibodies bind with the food. These antibody-food complexes can travel through the bloodstream to any part of the body where they then cause problems. There are many causes of “leaky gut” including immaturity, toxins, nutritional deficiencies, inflammatory bowel disease, poor digestion, and food allergies. There is a vicious cycle involved with these internal factors since the leaky gut also causes them or contributes to their severity.{4} (See The Ultimate Food Allergy Cookbook and Survival Guide for more information about these factors and the intestinal infections discussed below).
Last, but by no means least, “unfriendly” organisms present in the digestive tract can cause increased intestinal permeability. These infections can involve protozoan parasites, yeasts such as Candida albicans, bacteria that are conventionally considered “pathogens,” such as Salmonella, or an overgrowth of bacteria usually considered nonpathogenic, such as Klebsiella, Proteus, or Pseudomonas. Many other organisms not mentioned here can also increase intestinal permeability.
Most of the factors that increase intestinal permeability can be treated or eliminated from the lives of patients with food allergies. By doing this, the “why” of our leaky guts can be treated, and therefore our food allergies can be lessened and our health can be greatly improved.
Footnotes:
1. Reno, Liz, M.A. and Joanna Devrais, M.A. Allergy Free Eating, Celestial Arts, Berkeley, CA, 1995, pp. 22-23 and Braly, James, M.D. Dr. Braly’s Food Allergy and Nutrition Revolution, pp. 44-45.
2. Reno, Liz, M.A. et al, Allergy Free Eating, p. 26.
3. Ibid, p. 18.
4. Galland, Leo, M.D. “Leaky Gut Syndromes: Breaking the Vicious Cycles,” Townsend Letter for Doctors, August/September 1995, p. 62, and Reno, Liz, et al, pp. 62-63 and Reno, Liz, et al, pp. 19-20.
The information on this page is abridged from
The Ultimate Food Allergy Cookbook and Survival Guide ($24.95, eBook $13) © 2007
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