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Food Allergies vs. Food Intolerances

by Dr. Stephen Wangen

Allergy image
The most common example of a food intolerance is a digestive enzyme deficiency, such as lactose intolerance, in which a person cannot properly digest milk products.

The terms food allergy and food intolerance are frequently misunderstood and misused. They cause confusion even among doctors and other members of the medical community. Although they are sometimes used interchangeably, they really refer to two different types of physiological events. With an allergy, the body’s immune system attacks something that it shouldn’t. However, an intolerance doesn’t arise from the immune system at all. It is important that we more thoroughly define these two types of reactions to food.

Allergies
Allergies are reactions that involve the immune system. The immune system is very complex and is still not very well understood. But basically, it functions like a sentinel standing guard against foreign invaders – in the case of allergies, the invaders are allergens. One weapon it uses against invaders is the production of antibodies, which cause reactions that result in the offending allergens being removed from the body, often via an inflammatory process.

Foods should not normally trigger an immune response. Unfortunately, all too often, they do, and the immune system produces antibodies that target the food and circulate throughout the body, which is why an allergic reaction can show up in such a variety of symptoms just about anywhere in the body. These antibodies in turn trigger inflammation, which can result in pain and tissue damage, leading to further symptoms. The immune response can also produce excess mucous or, in the case of celiac disease, an autoimmune reaction that damages the lining of the digestive tract.

With an allergy, the body’s immune system attacks something that it shouldn’t. However, an intolerance doesn’t arise from the immune system at all.

It is not understood why an allergy to a given substance is expressed so differently in different people. Some people get hives and swelling of the lips and tongue. Others get digestive problems, migraines, or arthritis. Each individual seems to have a unique weak point where symptoms show up first. However, more research continues to be published that demonstrates a connection between various health problems and an immune response to food.

Intolerances
Strictly speaking, food intolerance is any type of non-immune reaction to or problem with a food. The most common example is a digestive enzyme deficiency, such as lactose intolerance, in which a person cannot properly digest milk products.

Some people have an intolerance to fructose, a type of sugar molecule. A person with a fructose intolerance does not digest or tolerate this molecule well. Fructose is found in many foods, such as fruits, and is derived from foods such as corn for use as a sweetener in processed foods. It is often listed on labels as high fructose corn syrup.

Another example is when people experience stomach pain or heartburn after eating spicy food. Although this can be caused by an allergy, in most cases it is simply a negative reaction to these foods that appears to have nothing to do with the immune system. This type of reaction also does not appear to be an enzyme deficiency.

Other intolerances include reactions to preservatives (such as sulfites and nitrites), colorants (FD&C colors), and flavorants (such as monosodium glutamate and aspartame). There are certainly other food intolerances, many of which have yet to be discovered or defined. Medically speaking, we classify these poorly understood reactions to foods or food additives as intolerances; they are also sometimes called sensitivities, another poorly defined word. There is no technical distinction between an intolerance and a sensitivity. Both are catch-all terms.

 

Dr. Stephen Wangen is a nationally recognized expert in the field of gluten intolerance, a gluten-intolerant physician, and cofounder of the IBS Treatment Center.

Reprinted with permission from Healthier without Wheat: A New Understanding of Wheat Allergies, Celiac Disease, and Non-Celiac Gluten Intolerance by Dr. Stephen Wangen, copyright © 2009 by Stephen Wangen.

This article was originally published in Coping® with Allergies & Asthma magazine, September/October 2011.