What are Food Allergies?
Food allergies may be one of the most prevalent health problems in our country. But if you're like most people, you're probably pretty sure you don't have one. The most common understanding of food allergies is that they cause obvious skin reactions like hives, a rash, or dangerous anaphylaxis. In fact, food allergies can be the cause of many chronic health problems.
What is an Allergy?
An allergy is what results when your immune system is inappropriately activated. Your immune system is designed to attack bacteria, viruses and parasites. It is not intended to attack the food you eat. But this is exactly what happens with some people. This is called a "food allergy" .
When your immune system is activated, antibodies (also called immunoglobulins) are produced. Antibodies in turn trigger an inflammatory response. Inflammation causes pain and tissue damage, leading to further symptoms. Increased mucous production is another aspect of an immune response.
When a food is broken down and absorbed, it is distributed through your bloodstream to all of your tissues. Therefore an allergic reaction can occur just about anywhere in your body.
We don't really understand why a food allergy can exhibit itself so differently in different people. However, every individual is unique and seems to have a unique weak point where symptoms of a food allergy show up first.
Most allergists rely on skin prick testing. It is by far the most common type of allergy testing performed in the United States and many allergists do not offer any other types of testing. Skin prick testing can very effectively determine if the patient will develop a skin rash when challenged with a particular allergen (material). Unfortunately not all allergic responses occur as skin reactions. Inflammation can occur in other parts of the body, and can sometimes occur long after the exposure to the material.
The immune system produces several different types of antibodies (immunoglobulin). The type that produces a quick rash in the skin is known as immunoglobulin type E (IgE). The antibodies that are deeper in your body and produce a reaction that can be delayed by hours or even days is type G (IgG). Another type is type A (IgA) w which is active in celiac disease - an autoimmune disease that is essentially an allergy to the gliadin protein in wheat and other related grains.
Studies (see our page of published research) have shown that food allergies can cause a variety of health problems. The evidence indicates that many of the problems related to digestion (such as Irritable Bowel Syndrome - IBS) and inflammation (such as juvenile rheumatoid arthritis) are related to food allergies. The Food Allergy and Intolerance Foundation supports testing for food allergies using the best available methods for any condition where inflammation not otherwise explained may play a role.
The best way to measure immune response to a challenge is to directly measure the antibodies that react to the challenge material. The technology most often used for this purpose is Enzyme Linked Immunosorbent Assay (ELISA). The ELISA technology is similar to that used in pregnancy test kits. However, when it is used to detect antibodies, especially those with low concentrations in the blood (like IgG) very high accuracy and precision are required. Unfortunately only a few labs in the country are offering this type of testing at present. Worse still, not all are employing measurement controls and other quality controls that enable them to produce reliable results. There are also some non-scientifically valid forms of allergy testing being offered by various kinds of health practitioners. These tests should be avoided as they produce misleading or completely inaccurate results.
For more information about testing for Food Allergies, check out the website of our partner the Center for Food Allergies.
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