Food Allergy or Food Intolerance? How to Tell the Difference

After finishing a delicious meal, you suddenly feel itchy and your stomach hurts. Could the problem be caused by a food allergy or a food intolerance? It can be difficult to tell at first, but there are signs that can help you get to the root of the problem.

Food Allergy Facts

Many people assume that when they have a reaction to a food or drink, it must be a food allergy. Yet food allergies are actually rarer than you think. In fact, only about 2.5 percent of people living in the United States have food allergies, according to a study published in The Journal of Allergy and Clinical Immunology in late 2010. Despite the rareness of the problem, the number of food allergy cases has been on the rise in recent years, with men and children seem to be particularly vulnerable.

Food Allergy vs. Intolerance

Here's the difference: If you have a food allergy, your body believes something you've consumed is dangerous and launches an immune system attack against it. With a food intolerance, your immune system doesn't get involved at all. Instead, a food intolerance is caused by anything from a missing enzyme that your body needs to appropriately digest an item (such as the case with lactose intolerance) to sensitivity to certain preservatives that causes a reaction.

The Signs of Food Allergies and Intolerances

Both food allergies and intolerances can present themselves in very similar ways, making it difficult to differentiate between the two conditions. Some of the symptoms you might experience with both a food allergy and intolerance include:

  • Cramping and diarrhea
  • Nausea and vomiting
  • Tingling mouth
  • Swelling lips, tongue, and face
  • Hives
  • Difficulty breathing

Three Clues to Help You Decide

Despite the similarities, the following clues can help you identify food allergies and intolerances so you'll be able to narrow in on what's causing your distress:

  1. With a food allergy, even the smallest exposure to the offending food will likely spark a serious reaction. With intolerance, a small amount of the food probably won't trigger any reaction; you'll need to consume larger quantities in order to feel ill.
  2. Food allergies may get increasingly severe with subsequent exposure to the trigger, while food intolerances are less likely to change.
  3. A food allergy reaction often occurs very quickly after consuming the food or drink, while food intolerance reaction could be delayed by a few hours.

Protect Yourself from Food Allergies and Intolerances

It's important to understand that while both a food allergy and intolerance can make you feel pretty sick, food intolerance usually won't be dangerous, but a food allergy can be life-threatening. This is why it's important to find out which one affects you.

Keep a food diary to track your diet and your symptoms, and share this information with your doctor. This way he can help you get the right diagnosis. If he suspects you have a food allergy, you'll also need to undergo allergy testing to confirm it. (There's no test to diagnose food intolerance so you'll need to rely on trial and error to determine what's making you sick.) In either case, it's best to avoid foods that cause a reaction. If you do have a food allergy, you'll need to carry injectable ephinephrine and be prepared to seek emergency medical care in case you experience a problem.




"Chronic Diseases: Food Allergy vs. Food Intolerance." Palo Alto Medical Foundation., 2011. Web. 12 April 2011.

"Diseases 101." American Academy of Allergy, Asthma and Immunology. AAAAI, n.d. Web. 13 April 2011.

"Food Allergy Vs. Food Intolerance: Telling Them Apart And Learning How To Manage Them." The Early Show/Saturday Morning. CBS News, 28 Feb. 2004. Web. 12 April 2011.

Li, James T., M.D. "Food Allergy." Mayo Clinic. Mayo Foundation for Medical Education and Research, 5 June 2009. Web. 12 April 2011.