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Food Sensitivities vs. Food Intolerances vs. Food Allergies

Updated: Jul 19, 2022

By: Meredith Hawk, MS, RDN, LD

There is a LOT of “diet advice” floating around based on food sensitivities-Or is intolerances?-Or is it a food allergy? You see where I’m going! Difficulty with digesting food is a POPULAR topic right now. So, how do you determine whether you have a sensitivity, an intolerance or an actual allergy to a certain food? The first thing we can do is break down the meaning of each term (3):

Food Sensitivity-A term used by blood test makers to detect “sensitivities” to foods. This term is NOT an actual medical diagnosis.

Food Intolerance- This term is referring to difficulty with digesting or metabolizing certain foods.

Food Allergy- An adverse immunological response caused by certain foods.

While food intolerances are more common at 15-20% of the population, true diagnosed food allergies only make up about 10% of the population (both adults and children combined) (4). Typically food allergens are proteins (2). There are 8 foods that are most commonly the culprits for food allergies (4):

  1. Milk

  2. Eggs

  3. Peanuts

  4. Tree nuts

  5. Fish

  6. Shellfish

  7. Wheat

  8. Soy

If we break it down even further, there are both IgE-mediated reactions (i.e. immediate onset of symptoms) & non-IgE mediated food allergies (i.e. Eosinophilic GI Disorder/ Celiac Disease). Classic, IgE-mediated reactions are defined as IMMEDIATE onset of the below symptoms (4):

  • Cough

  • Chest tightness

  • Wheezing

  • Hives

  • Nausea

  • Vomiting

  • Diarrhea

  • Bloating

  • Dermatitis

  • Angioedema

  • Life threatening anaphylaxis

Food intolerance issues are typically seen up to 3-6 hours later (4). They may include symptoms such as (2):

  • Excessive intestinal gas

  • Bloating

  • Abdominal pain

  • Diarrhea

Typically with food intolerances you see the following: 1.) the gastrointestinal system (GI) tract is involved and 2.) the reactions are generally directly correlated to the amount of the food consumed (3). With a true food allergy, even the smallest, minute amount can cause a reaction (2).

So how do we go about testing for food allergies or intolerances or sensitivities? If you, along with your Primary care physician, suspect food allergies, a consultation to an Allergen Specialist is advised. While there are many food sensitivity tests on the market available for home use, it is important to be aware that these tests are typically looking for IgG’s (NOT IgE’s). These tests are considered unreliable as most people will produce IgG’s after the consumption of foods, which does not indicate how sensitive a person is to the specific food (3). Skin prick-tests, allergen-specific IgE testing and clinical history are all needed to confirm a true food allergy (4). Dependent upon the reaction, a supervised oral challenge may occur or if the risk is considered moderate. A low risk reaction may prompt a gradual re-introduction of trigger foods at home (4). The most practical way to deal with a food allergen is 1.) Avoid the allergen 2.) Read labels 3.) Be aware of potential cross contamination and 4.) If necessary, your provider will prescribe you with an epinephrine injector (i.e. an “epi” pen).

Combating food intolerances is something that can be handled through a modified diet. The low FODMAP diet is a popular diet in helping with symptom management of food intolerances. Onyimba et. Al describes FODMAPS as “fermentable oligo-,di- and monosaccharides and polyols such as fructose, fructans, sucrose, lactose, and sorbitol that are poorly absorbed, rapidly fermented, and osmotically active” (4). All of the above are forms of carbohydrates. So what does that mean for us? The carbohydrates listed are being malabsorbed causing the gut bacteria to produce excess gas and pull water into the intestine which results in GI upset (i.e. the gas, cramping, bloating, diarrhea, etc.) (1). While the low FODMAP diet is beneficial, it is restrictive of certain nutrients and should be done within a certain time frame and under supervision. The ultimate goal is to figure out which foods are triggers for you, so that you’re not unnecessarily eliminating certain foods. If you suspect a food intolerance and desire to know more about the low FODMAPs diet, it is recommended you do so under the supervision of a Registered Dietitian.

While the terms may get confusing at times, just remember a true food allergen will cause an immune response; a food intolerance will cause a response but generally not right away and the GI system is involved; a food sensitivity is not truly a medical term, but generally refers to testing. If you want more information, speak with a Registered Dietitian or your MD.


  1. Castos, P., Scarlata, K., Van Dams, L. (2020). Nutrition Therapy, The Low FodMAP Diet. Ditetitians in Medical Nutrition Therapy, 1-4.

  2. Commins, SP., (2020). Food intolerance and food allergy in adults: An overview. Up To Date, 1-30. <>.

  3. Gordon, B. (2019). Are Food Sensitivity Tests Accurate? Academy of Nutrition and Dietetics. <>.

  4. Onyimba, F., Crowe, S.E., Johnson, S., Leung, J. (2021). Food Allergies and Intolerances: A Clinical Approach to the Diagnosis and Management of Adverse Reactions to Food. Clinical Gastroenterology and Hepatology, 19,2230-2240.

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