Is It Food Allergy or Food Intolerance?

A Veteran with an upset stomach Do certain foods make you itchy or cause an upset stomach?

Physical reactions to certain foods are common, but a food intolerance or a food allergy cause most such problems.

A food allergy occurs when you eat something that abnormally triggers your body's immune system. Sometimes even a tiny amount of a food can trigger such a response. The body may respond to the food allergen (something that causes an allergic reaction) with such symptoms as digestive problems, hives or an impaired airway. In some cases, the reaction may be life threatening and cause anaphylaxis. Anaphylaxis is a severe whole body reaction to an allergen.

Foods often associated with allergic reactions:

  • Fish and shellfish

  • Peanuts, walnuts

  • Eggs

Food intolerance is different from a food allergy. Food intolerance is a reaction to a food that does not involve the body's immune system. While the reaction may feel as if it is a food allergy, if the immune system is not responding, it is food intolerance. Sometimes it is an additive to a food that may trigger the intolerance symptoms. Some common intolerance in adults are:

  • Monosodium glutamate (MSG) is a flavor enhancer which, in large amounts, can cause such symptoms as flushing, headache and chest discomfort. MSG is found in prepared foods such as sauces, dressing, chips, and seasonings.

  • Sulfites occurs in some foods, such as some wines, and used in food to increase crispness. Intolerance to sulfites can cause breathing problems for people with asthma.

Lactose intolerance defines food intolerance to a sugar, lactase, found in milk and milk products. While uncommon in young children, it is more common in adults. The enzyme needed to break down the lactase declines as people age. When lactase is not broken down by the needed enzyme, the gut may respond with symptoms such as abdominal pain, bloating and diarrhea. Your doctor can run some laboratory tests to determine if you have lactose intolerance.

It may take a little detective work to figure out which foods trigger your allergy symptoms. But one thing that can help is to use My HealtheVet's Self-Entered Allergies and Food Journal features. You can record what you eat and when you discover that you get allergy symptoms, look for patterns.

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Updated February 26, 2020