This article has been reviewed by Thanai Pongdee, MD, FAAAAI
Some of the symptoms of food intolerance and food allergy are similar, but the differences between the two are very important. Eating a food you are intolerant to can leave you feeling miserable. However, if you have a true food allergy, your body’s reaction to this food could be life-threatening.
Digestive system versus immune system
A food intolerance response takes place in the digestive system. It occurs when you are unable to properly breakdown the food. This could be due to enzyme deficiencies, sensitivity to food additives or reactions to naturally occurring chemicals in foods. Often, people can eat small amounts of the food without causing problems.
A food allergic reaction involves the immune system. Your immune system controls how your body defends itself. For instance, if you have an allergy to cow’s milk, your immune system identifies cow’s milk as an invader or allergen. Your immune system overreacts by producing antibodies called Immunoglobulin E (IgE). These antibodies travel to cells that release chemicals, causing an allergic reaction. Each type of IgE has a specific “radar” for each type of allergen.
Unlike an intolerance to food, a food allergy can cause a serious or even life-threatening reaction by eating a microscopic amount, touching or inhaling the food.
Symptoms of allergic reactions to foods are generally seen on the skin (hives, itchiness, swelling of the skin). Gastrointestinal symptoms may include vomiting and diarrhea. Respiratory symptoms may accompany skin and gastrointestinal symptoms, but don’t usually occur alone.
Anaphylaxis (pronounced an-a-fi-LAK-sis) is a serious allergic reaction that happens very quickly. Symptoms of anaphylaxis may include difficulty breathing, dizziness or loss of consciousness. Without immediate treatment—an injection of epinephrine (adrenalin) and expert care—anaphylaxis can be fatal.
When to See an Allergist
• If you think you might have a food allergy.
• If you have limited your diet based on possible food allergy.
• For the best diagnosis, as well as treatment and avoidance measures for food allergy.
To the Point
There is a very serious difference between being intolerant to a food and having a food allergy.
Find out more about food allergies.