Food Allergies vs. Food Intolerances: What’s the Difference?

Posted 6.29.10 | Nutrition Specialist

Anyone who has eaten something and then experiences an unpleasant reaction has probably wondered if they have a food allergy. In fact, one out of three individuals thinks they may have a food allergy or may modify their diet due to a suspicion. Occuring to AAAAI statistics, yet only around 6% of children under the age of three are affected by food allergies, but most out grow these allergies as adults.

What all of this adds up to is that food allergies and food intolerances can be easily confused with each other. Yet these conditions are different in terms of their origin, symptoms and treatment. So what are the differences between the two?

What Are Food Allergies?

Let’s start with the more severe of the two: food allergies. Food allergies occur when the body’s immune system identifies a food as a harmful substance. When the body recognizes anything harmful it will produce antibodies, which are like small soldiers that protect our body’s health. When the body produces antibodies directed against a certain type of food, it causes an immune response. This then releases histamine and other chemicals that trigger allergic symptoms. These allergic symptoms are ‘red alerts’, which tell us that something is wrong.

Generally, it is the protein in foods that cause an allergic reaction. Food allergy symptoms may occur right after consuming the allergen or even hours later. These symptoms may affect the respiratory system, gastrointestinal tract, cardiovascular system or the skin. In cases of severe allergic reactions there may be a drop in blood pressure or loss of consciousness. Some people have food allergies so severe that they are at risk for life threatening reactions known as anaphylaxis. Anaphylaxis is a rapid series of serious allergic reactions that affect a number of different areas of the body at once. Fortunately, this can be treated with the prescription drug epinephrine, which is available on-the-go in a pen size injector – also known as an Epi-Pen.

Common food allergy symptoms include:

  • Skin rash or hives;
  • Swelling of the tongue and throat;
  • Breathing problems including asthma;
  • Vomiting and/or diarrhea; and
  • Abdominal pain and cramping.

Currently, there are no medications that cure food allergies, so it is necessary for children and adults with food allergies to avoid allergenic foods. It is critical to review food labels and ask questions about ingredients in recipes before consuming any foods. The Food Allergen Labeling and Consumer Protection Act of 2004.

What Is A Food Intolerances?

Food intolerance is the inability to properly digest or fully process certain foods. This does not involve an immune response, but is still an adverse food-induced reaction that can cause uncomfortable symptoms similar to a food allergy. For example, lactose intolerance is caused when a person lacks an enzyme called lactase that breaks down the milk sugar called lactose. This can cause gas, bloating and abdominal pain when consuming milk products. Fortunately, lactase tablets are available without a prescription to help treat this food intolerance.

Because the symptoms of food allergies and intolerances are often similar, it is helpful to get tested by an allergist and keep a food diary. A food diary keeps track of which foods are eaten and at what time, which can help determine if they are causing the symptoms of an intolerance or allergy. This will help the allergist to distinguish the correct diagnosis and treatment. Allergists can also conduct a skin test or blood test to determine if an individual is allergic to a specific food. How did you determine if you or your child had a food allergy or food intolerance? Did you find allergy testing to be reliable, or was keeping a food diary more helpful?

- Reneé

Read Comments (2)

  • 2011-06-11 | Michelle Weeden

    My son had blood in his stool and the Dr. gave him Neocate.
    I just started my son on Neocate (about 4 days ago) and he has had 2 episodes of projectile vomiting. Should I be concerned and how long does it take for his body to adjust to he new formula?

  • 2011-06-23 | Rob McCandlish, RDN

    Hi Michelle,

    I’m Rob, one of the Nutrition Specialists here at Nutricia. Every child responds a little bit differently to Neocate, and symptoms can take anywhere from about 3 days up to 2 weeks to show improvement. For more specific questions, like yours, please contact us directly; by email any time - .(JavaScript must be enabled to view this email address); by phone during business hours - 800.365.7354 option 2; or during business hours using the chat feature on the left-hand side of your screen when you’re here:

    We look forward to hearing from you and helping to answer your questions.
    - Rob

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About Us

Food Allergy Living is a resource for parents of children with food allergies, brought to you by Nutricia, the makers of Neocate. For more in-depth information about our purpose & authors, see our About Food Allergy Living page.