Food allergies and intolerances

Food allergies and intolerances are a hot topic these days, but these terms are often used incorrectly and can lead people to follow unnecessarily restrictive diets. Here is a brief overview to bring up to speed and help you ask the right questions.

Food allergies

People have true allergic reactions to food when their immune system produces IgE antibodies against food. When someone has a food allergy their reaction to that food can range from a rash to a life-threatening episode of anaphylactic shock.

A less well-known type of allergy is Oral Allergy Syndrome. When someone has OAS they may experience itching or swelling in their mouth when they eat certain raw fruits or vegetables, but can usually tolerate a cooked version of the same food. OAS is usually not life-threatening, but it is best to talk to your doctor or allergist about your risk level

Food intolerances and sensitivity

The terms food intolerance and food sensitivity are used, sometimes inaccurately, to describe a variety of experiences and symptoms. While there is no standard definition for food sensitivity, a food intolerance does not involve the immune system and typically involves the digestive system. Food intolerance occurs when people have trouble digesting certain foods, additives or naturally occurring chemicals.

When this happens people often experience excess gas, abdominal pain and diarrhea. Probably the most widely known intolerance is lactose intolerance which occurs when an individual does not produce enough of the digestive enzyme lactase to digest the lactose in dairy products. For example, someone with lactose intolerance may tolerate cheese or a small portion of yogurt or milk, but might experience excess gas and diarrhea if they consume a typical serving of milk or ice cream.

How to get answers

Many companies advertise unproven tests that claim to diagnose dozens of different food allergies, intolerances and sensitivities. They often make bold claims about the benefits of following diets based on this testing and provide long lists of food to avoid. Food Panel IgG testing and hair testing are popular but have not been proven to diagnose food sensitivities or allergies. In fact, certain types of IgG antibodies may actually be associated with tolerance of foods.

If you suspect you have a food allergy, sensitivity or intolerance it is important to talk to your doctor. Food allergies can be life-threatening and certain digestive symptoms can be signs of serious conditions such as Crohn's disease, Celiac disease or cancer.

Getting an accurate diagnosis is important because it helps you get the care you need and lets you follow the least restrictive diet possible to manage your symptoms. Eliminating foods without guidance or evidence can lead to frustration, malnutrition, social isolation and missing out on the care you deserve. Consult with a registered dietitian after diagnosis to help you sort out an appropriate diet.