What’s the Difference Between a Food Allergy and a Food Intolerance?

I am often asked, “what’s the difference between a food allergy and a food intolerance?” The answer is – A LOT! A food allergy is really serious and shouldn’t be taken lightly. It’s not something like, “oh I’m allergic to milk but if there’s cheese on a sandwich, I’ll be okay,” or, “I’m allergic to peanuts, so I’ll just have one or two.”

One of my biggest pet peeves are people that throw around the word “allergic,” when they have not been properly tested or even assessed by a board-certified allergist. I’ll give you a hint, if your acupuncturist told you to say away from dairy because Mercury is in retrograde – YOU DO NOT HAVE AN ALLERGY. If you ate soy once and it made you break out with acne the week after, you’re not allergic. Please don’t undermine the seriousness of a true food allergy.

What's the difference between a food allergy and a food intolerance?

What Is a Food Allergy?

A food allergy is a serious condition that can lead to anaphylaxis or death, as an over reaction from your immune system to a otherwise-harmless food. Food allergies are most often brought on by one or more of the eight most common allergic foods – peanuts, tree nuts, milk, wheat (not gluten), soy, egg, fish, and shellfish. A food allergy can be diagnosed through a careful review of past history with foods with a board-certified allergist, including any past issues with foods/reactions, as well as a blood test (IgE) and/or skin prick test. If you consistently eat a food and it doesn’t bother you, you are not allergic to it. You can’t have a mild allergy to something. As FARE puts it, “There are no mild or severe food allergies—only mild to severe reactions.” However, while you may have a positive blood test or positive skin prick test, it’s up to you and your allergist to discuss oral challenge and/or past history eating the offending food to determine if you have a true food allergy. If you have a food allergy, you’ll need to be prepared with an action plan and epinephrine in case of a severe reaction. Learn more about food allergies from FARE.

What Is a Food Intolerance?

A food intolerance is a less-serious reaction to food, after a food allergy has been ruled out. These reactions to food are not based on immune response, they are not always reproducible (doesn’t happen every time you have the food), and not always immediate (KWFA, 2015, Stukus)

There are many tests on the market that supposedly help you find foods that you can’t eat. Don’t trust any of them.

The following is a list of things that cannot test for food intolerances:

  • IgG tests (that’s right, all those “sensitivity tests” don’t really test sensitivity, they test tolerance. IgG does not have clinical relevance and is not validated. Don’t buy them, or rely on them to make any of your food decisions for you.
  • Hair analysis, stool analysis, urine analysis, or saliva tests that are marketed to find food sensitivities.
  • Muscle testing. Anyone that uses muscle testing is a fraud. Really – you hold a piece of bread over you and somehow your body “tells” the doctor that you can’t eat it? Bro, do you even science?

What’s the Best Food Sensitivity Test?

Now, if all these things can’t test for food sensitivities, how do you get tested for food sensitivities? Is there a food sensitivity test that’s valid? What’s the best food sensitivity test? A good, old fashioned elimination diet. That’s right, eliminating a food for a period of time and then reintroducing foods, one at a time, to see if you have any symptoms (stomach upset, skin rashes, brain fog, etc.). Need help with an elimination diet? Seek out a dietitian.

Food Allergy or Food Intolerance Infographic from National Jewish Health
Image Courtesy of National Jewish Health

Is Celiac Disease a Food Allergy?

I’m also asked a lot, “Is celiac a food allergy?” The short answer is no. Celiac disease is a genetic autoimmune disease that is triggered by the consumption of gluten. While it may seem like an allergy, as we are affected by what we eat – and it is sure easier to say that you have an allergy at a restaurant – technically we don’t have a food allergy. However, you still must strictly avoid gluten, as if it were a serious food allergy. Learn more about celiac disease in my article about celiac disease screening and celiac disease testing.


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1 comment

  1. Vanessa May 26, 2019 at 10:39 pm Reply

    Unfortunately, not everyone can afford a doctor willing to check if they have an allergy or intolerance.

    I’m pretty sure I have an intolerance now, but I spent 7 years with a nasty rash and I had several doctors who would prescribe creams but wouldn’t do any tests even when I asked. Never was the word intolerance even mentioned.

    Sometimes it’s just easier to say allergy so people will tale it seriously.

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