Food Allergies vs. Food Intolerance

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Reviewed on 6/13/2018 12:00:00 AM

Sometimes people become sick from eating a particular food, because they cannot properly process or digest the food, or because they have a true allergic (immune) reaction to the food. Food allergies and food intolerance are sometimes confused with each other, but they are quite different in terms of their origin, symptoms and treatment.

Food Allergies

True allergic reactions to food involve the body's immune system. When the body identifies a food as harmful, it produces antibodies directed against that food. The next time the food is consumed, the body mounts an immune response with the release of histamine and other chemicals that trigger allergic symptoms. A common example of a food allergy is to peanuts.

With a food allergy, symptoms may occur almost immediately or up to hours after consuming the particular food. These symptoms may affect the respiratory system, gastrointestinal tract, cardiovascular system, or the skin.

Food allergy symptoms can include:

Severe allergic reactions may result in a drop in blood pressure, loss of consciousness, or even death.

There are no medications that can cure food allergies. Diligent avoidance of the offending food is the only sure way to prevent a reaction. People with food allergies must thoroughly examine food labels and ask questions about the ingredients of dishes. For example, the label on a breakfast cereal may read: "May contain soy, peanuts and/or other tree nuts."

Severe life-threatening allergic reactions can be treated with the prescription drug epinephrine. This drug is available as a pen-style injector.

Food Intolerance

Food intolerance is different from food allergy in that it does not involve an immunologic reaction. A common type of food intolerance is lactose intolerance. Persons with lactose intolerance lack an enzyme (called lactase) needed to digest the milk sugar (called lactose). They can develop gas, bloating, and abdominal pain when they consume milk products.

Some types of food intolerance can be treated. For example, lactase tablets are available without a prescription to aid those with severe symptoms of lactose intolerance and lactose-free dairy products are available at most supermarkets.

If an individual thinks they may have either food allergy or food intolerance, keep a diary of the foods eaten and any symptoms experienced. A food diary can help the doctor establish the correct diagnosis. A doctor can also order simple skin tests or blood tests to determine if an individual is allergic to specific foods. The strategy of dealing with a food allergy is different than dealing with food intolerance.

REFERENCE: MedscapeReference. Food Allergies.

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