|Food Allergy Center|
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Delayed Patterns of Food Allergy... Beyond Skin Tests
For some time, it has been appreciated that delayed patterns of food allergy cause chronic illness. The term "delayed" is helpful only because it alerts readers with little knowledge of immunology to a simple distinction between immediate reactions that are easy to recognize and illness patterns that emerge slowly. There are a number of different and immune mechanisms that are activated by food and operate in more complex and mysterious ways.
Although skin tests are still used to test for food allergy, some allergists recognized the limitations of skin tests and prescribed low allergy or elimination diets with satisfactory results. Allergists generally appreciated that allergy desensitization shots containing food antigens were not helpful.The desire for simple, definitive tests for food allergy is easy to understand, but difficult to fulfill. Food interacts complexly and sequentially with many different consequences. It is unlikely that food allergy occurs in a consistent manner; there are too many variables. No single test will ever reveal the complex and variable nature of this reactivity. The lack of specific tests for food allergy have hindered progress in this field.
Proteins Cause Food Allergy
Increased intestinal permeability to food proteins explains the whole body effects of food allergy. The association of Crohn's and celiac disease, for example, with psoriasis and arthritis suggests that increased uptake of food antigens from the digestive tract can be the mechanism of systemic inflammatory disease. The absorption of short-chain peptides derived from food has profound biological significance since receptors to peptides abound in the body and peptides of about 9 amino acids and longer can act as antigens. Great numbers of different peptides can be produced by digestion.
Food protein antigens make their way through human bodies in a remarkable fashion. Every tissue of the body can host a food allergic response. Some activity is noticed in minutes; usually the onset is delayed hours to days. Manifestations include whole body symptoms such as flushing, fever, aching, fatigue, and also localized target organ activity, usually some form of inflammation, felt as pain, swelling, redness and local heat.Food Allergy and Flu-like symptoms
Flu-like symptoms are typical manifestations of the delayed patterns of food allergy - patients often complain of fatigue, irritability, aching, and cognitive dysfunction. Many say they are "sick-all over". The delayed mechanisms of food allergy tend to produce recurrent or chronic symptoms. Non IgE mechanisms are responsible for delayed patterns of food allergy that are prevalent and produce symptom complexes both generally and in target organs such as the gastrointestinal tract. These mechanisms are not demonstrable by skin tests.
The basic idea is that delayed food allergy begins in the gastrointestinal tract mucosa and spreads inward to any body tissue if food antigens enter the circulation and interact with the circulating immune system. Incoming food antigens tend to form immune complexes, and can injury target organs by triggering inflammatory responses in a variety of ways.