The Role of Hidden Food Allergy/
Intolerance in Chronic Disease

This section is compiled by Frank M. Painter, D.C.
Send all comments or additions to:    Frankp@chiro.org

FROM:     Alternative Medicine Review 1998 (Apr); 3 (2): 90-100 ~ FULL TEXT

Alan R. Gaby, M.D.

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Food allergy is well recognized in clinical medicine as a cause of acute attacks of asthma, angioedema and urticaria, and as a contributing factor in some cases of eczema and rhinitis. These types of allergic reactions are considered to be mediated by IgE antibodies, and usually can be diagnosed by medical history and skin-prick or IgE-radioallergosorbent (RAST) tests.

Another type of food reaction, often referred to as "hidden" or "masked" food allergy, has been the subject of controversy for many years. Some practitioners have observed that hidden food allergies are a common cause of (or triggering factor for) a wide range of physical and emotional disorders. According to one estimate, as many as 60 percent of the population suffers from undetected food allergies. [1] A wide range of symptoms and disorders are reported to have a significant allergy component. See Table 1. On the other hand, many conventional physicians doubt hidden food allergy is a common problem, and some even deny altogether its existence as a clinical entity.

Skeptics emphasize the fact that many of the conditions said to be related to allergy fluctuate in severity and have a significant psychological component. Consequently, it may be difficult to distinguish between a true food reaction and a conditioned (psychogenic) response or a spontaneous exacerbation of symptoms. It also has been pointed out that food-induced symptoms should not be called allergies unless an immune-mediated mechanism can be demonstrated. While it is true many food reactions would be more appropriately labeled food intolerance, the term "allergy" will be used in this article in reference to adverse reactions to foods.

Proponents of the food allergy-disease connection argue that hidden food allergies are often overlooked because they are difficult to identify. Unlike the more obvious immediate-hypersensitivity reaction that can trigger acute asthma or anaphylaxis, a hidden food reaction frequently can be delayed by many hours or even several days.

Identifying a cause-effect relationship between ingestion of specific foods and development of symptoms is said to be further complicated by the tendency of people to become addicted to the foods to which they are allergic. This so-called "allergy-addiction syndrome" has been observed by numerous clinicians [2] and appears to be consistent with Selye's description of the "general adaptation" response to stress. [3,4] Thus, patients often experience short-term relief after ingesting foods which are later demonstrated to be the cause of their chronic symptoms. This paradoxical response can render medical histories and diet diaries virtually useless for detecting hidden allergies.

Hidden food allergies can usually be "unmasked" by means of an elimination diet. [5] After a patient has been on a hypoallergenic diet for a period of time (typically one to three weeks), chronic symptoms disappear or improve and the body reverts from a state of allergy-addiction (corresponding to Selye's adaptation stage) to one of increased alertness and sensitivity (corresponding to Selye's alarm stage). In this hypersensitive state, ingestion of an offending food results in a rapid and exaggerated reaction, allowing the patient to identify previously unsuspected allergens. See Table 2 for a list of foods most commonly associated with food allergies or intolerances.

Ideally, studies of hidden food allergy should be conducted using double-blind, placebo-controlled food challenges, in order to rule out placebo responses and spontaneous fluctuations in symptom severity. Some of the research reviewed in this article has used a double-blind design; and most of these studies have confirmed the importance of food allergy in the etiology of certain chronic conditions. Most of the other studies on food allergy have lacked placebo controls. Nevertheless, the results of these studies have frequently been impressive, especially when compared with results of conventional therapy. Following is a review of selected studies on the relationship between food allergy and certain common medical conditions.

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