Making Sense of Food Intolerance and Allergies

Few areas cause our patients more confusion than a food allergy, food intolerance and what this has to do with their digestive problems. Wherever you turn, there seems to be conflicting information; and your friends, relatives and lots of total strangers are happy to give you their opinions also.

To best educate oneself, it is essential to differentiate an allergy and intolerance. An allergy is the body’s reaction to the presence of toxins, bacteria or viruses by producing a chemical reaction to fight these invaders. This overreaction can cause symptoms from the mild hives to the severe, anaphylactic shock, upon subsequent exposure to the substance. A food allergy is an exaggerated immune response triggered by eggs, peanuts, milk, or some other specific food. Eight foods account for 90% of all food-allergic reactions. They are milk, egg, peanut, tree nuts, fish, shellfish, wheat, and soy. Food labels MUST list whether a food contains any of these!

Intolerance is a digestive system response rather than an immune system response. It occurs when something in a food irritates a person’s digestive system or when a person is unable to properly digest or breakdown, the food. Intolerance to lactose, which is found in milk and other dairy products, is the most common food intolerance, with gas, bloat and/or diarrhea typical symptoms. There are many factors that may contribute to food intolerance. In some cases, as with lactose intolerance, the person lacks the chemicals, called enzymes, necessary to properly digest certain proteins found in food. Also common are intolerances to some chemical ingredients added to food to provide color, enhance taste, and protect against the growth of bacteria. These ingredients include various dyes and mono-sodium glutamate (MSG), a flavor enhancer. Substances called sulfites are also a source of intolerance for some people. They may occur naturally, as in red wines or may be added to prevent the growth of mold. These cause asthma attacks in some. Salicylates are a group of plant chemicals found naturally in many fruits, vegetables, nuts, coffee, juices, beer, and wine. Aspirin also is a compound of the salicylate family. Foods containing salicylates may trigger allergy symptoms in people who are sensitive to aspirin. Of course, any food consumed in excessive quantities can cause digestive symptoms. Peptobismol contains a form of salicylate.

How can you tell the difference between a food allergy and intolerance?

Food allergies can be triggered by even a small amount of the food and occur every time the food is consumed. People with food allergies are generally advised to avoid the offending foods completely. On the other hand, food intolerances often are dose related. People with food intolerance may not have symptoms unless they eat a large portion of the food or eat the food frequently. For example, a person with lactose intolerance may be able to drink milk in coffee or a single glass of milk, but becomes sick if he or she drinks several glasses of milk. Allergy to actual milk protein is rare in adults; kids with this outgrow it early. Food allergies and intolerances also are different from food poisoning, which generally results from spoiled or tainted food and affects more than one person eating the food.

The best method for diagnosing true food allergy is to be assessed by an allergist. To best treat an allergy or intolerance, please visit your gastroenterologist. Additionally, supplementary information about causes and treatment for allergies and intolerance can be found on our Patient Education Page.