What’s The Difference between a Food Allergy, Sensitivity, and Intolerance?

Thursday, August 30, 2018
Alyssa O’Brien, RDN, LD

Do I have a food allergy, sensitivity, or intolerance? What’s the difference?

These are a common questions when trying to find a culprit for ongoing digestive symptoms. All of these conditions can cause reactions in the digestive system like abdominal pain, bloating, or diarrhea, so it is understandably confusing to know what you’re dealing with. Additionally, these terms get thrown around loosely; sometimes used interchangeably. Ultimately, food allergies, sensitivities, and intolerances are distinct conditions that have different dietary treatments.

If you have a reaction to a food, the symptoms can be vague, but there are some specific gastrointestinal conditions associated with food allergies, sensitivities, or intolerances. For example, an inflammatory condition called eosinophilic esophagitis is associated with food allergies, and celiac disease is associated with gluten sensitivity (but also can rightly be called an allergy and gluten intolerance – confusing, I know!). Then, there is irritable bowel syndrome which is often caused by food intolerances. The most classic example of intolerance is lactose in milk products. It may be helpful to know that food intolerances are much more common than food allergies.  

Although allergies, sensitivities, and intolerances can present with similar reactions, there are a few key differences to sort it out.

Food Allergy

  • An immediate immune response with IgE antibody production triggering histamine release
  • Affects about 4% of adults according to the CDC
  • Allergies can be developed at any age and to foods that you have eaten before
  • Common symptoms: hives, swelling of throat, lips, or tongue, abdominal pain, diarrhea, vomiting
  • Severe symptoms can lead to anaphylaxis

Food Sensitivity

  • Does not typically activate the immune system, but produces antibodies like IgA and IgG
  • Reactions can be delayed, but no risk for anaphylaxis
  • Can exacerbate inflammation in the body
  • Common symptoms: digestive issues, fatigue, headaches, skin rashes like eczema or dermatitis

Food Intolerance

  • Reactions occur exclusively within the digestive system
  • No antibody production and does not involve the immune system
  • Often caused by enzyme deficiencies or reactions to natural components or additives in food
  • Small amounts of the food may be tolerated
  • Intolerance may be temporary 
  • Common symptoms: heartburn, abdominal pain, bloating, gas, diarrhea or constipation

Is there a test for it?

Food allergy testing can be done with a blood test measuring IgE antibodies, or skin tests, which are considered more accurate. If you have a diagnosed or suspected allergy, you should avoid that food completely. Severe food allergies are not likely to go away, but in certain cases, the severity of reaction may diminish through dietary changes.

Similarly, blood tests can be run for food sensitivities using IgA, IgG, and other antibodies. These tests can help you quickly identify foods that may be causing symptoms, but should not be used as diagnostic tools. Keep in mind these test results can be unreliable and can change. 

An alternative and cheaper way to test for food sensitivity or intolerance is an elimination diet. This is where you eliminate certain foods for a period of time then reintroduce them while monitoring symptoms. If you are struggling to identify which foods are a problem for you, consider working with a qualified healthcare specialist that can safely help you through the process.  

At The Oregon Clinic, our dietitians are passionate about educating patients to eat to feel good and restore their digestive health. Learn more here and schedule an appointment with a dietitian today.



American College of Allergy, Asthma & Immunology. <https://acaai.org/allergies/types/food-allergy>

Food Problems: Is it an Allergy or Intolerance. Cleveland Clinic. <https://my.clevelandclinic.org/health/diseases/10009-food-problems-is-it-an-allergy-or-intolerance>

Li, James T C, MD, PhD. Food Allergy Vs. Food Intolerance: What’s the Difference? Mayo Clinic.

Non-Celiac Wheat Sensitivity. Celiac Disease Foundation. <https://celiac.org/celiac-disease/understanding-celiac-disease-2/non-celiac-gluten-sensitivity-2/>

Ballantyne, Sarah PhD. 2013. The Paleo Approach. (306-309). 

Aceves, Seema S, MD, PhD. 2016. Allergy Testing in Patients with Eosinophilic Esophagitis. Gastroenterology & Hepatology. Retrieved from NCBI. <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5114500/>