What is a Food Allergy?

Food allergies are much more complicated than most people, including most physicians, realize.

Food allergies are typically thought of as relatively uncommon reactions to a few select foods, such as peanuts, that usually result in anaphylaxis, hives, or maybe asthma. This is how most allergy specialists think of food allergies. However, there are numerous research studies that indicate that food allergies cause many other conditions.

Technically, an allergy is any reaction that involves the immune system. But the standard of practice in medicine is to use a much narrower definition of the word allergy. Therefore, in order to truly understand the breadth of allergic reactions, it is necessary to define some of the underlying mechanisms involved in allergies.

Conventional IgE Allergies

Classic food allergies are the result of an IgE (immunoglobulin E) reaction to a food. IgE is a type of antibody produced by the immune system. When the immune system is attacking a food, it may produce IgE antibodies. IgE antibody reactions are the kind of reactions that are involved in hives and other conventional allergic reactions as well as conditions such as reflux.

Many people are familiar with skin testing for allergies. Skin testing is the traditional type of food allergy testing. IgE reactions are the type of reactions that are being looked for when skin allergy testing is performed.

Skin tests, however, only assess whether or not the skin will react to something. They do not necessarily represent IgE levels in the blood, and they do not reflect other types of immune reactions, such as those more commonly found to cause reflux.

Some physicians are now using blood tests to measure IgE antibodies. This can be a bit more useful, but most cases of reflux are not caused by an IgE reaction to food. Therefore the food allergy will not show up on skin tests or on blood tests for IgE antibodies. Unfortunately, these tests will generally not be helpful in determining the cause of your child’s reflux.

Other Types of Food Allergy

As noted above, an allergy is any reaction that involves the immune system. And IgE antibody reactions are only one type of immune response to food. A majority of immune responses to food involve IgG reactions.

For example, let’s consider a gluten intolerance. Just to confuse you, the standard of practice in medicine is to call this an intolerance. However, it is an immune reaction, and it definitely involves an immune reaction against gluten, which is a protein in wheat and many other grains.

A gluten intolerance does not show up on skin tests or on IgE blood tests. But it does show up on blood tests for IgG antibodies. And yes, studies have clearly shown that these reactions to gluten can cause reflux.

As you can see, the use of the words “allergy” and “intolerance” can be very confusing. But to help clarify the picture a little, consider dairy.

Most people assume that a reaction to dairy is a lactose intolerance. Lactose is a sugar found in dairy products. A lactose intolerance is the result of an enzyme deficiency that causes an inability to digest lactose. This is not an allergy because it does not involve the immune system. However, a lactose intolerance can cause symptoms like gas, bloating, and loose stools. A lactose intolerance is not usually associated with reflux, while dairy allergy often is. Therefore, avoiding lactose but still ingesting dairy may not be enough to resolve reflux caused by a dairy allergy.

As a result, many people discover that in order to resolve reflux, all dairy must be avoided, not just lactose. Many studies have shown this as well. This is due to an all too common immune reaction to dairy. This reaction will usually show up on blood tests as an IgG antibody reaction to cow’s milk.

Dairy is usually the first non-breast-milk food introduced into the human diet, and is unfortunately the most likely to cause health problems, including reflux. What is even more interesting is that when you run IgG food allergy tests you frequently find reactions to dairy in reflux patients. And even more importantly, when you take them off dairy they get better.

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Image thanks to mercola.com