The Difference Between Food Allergies and Intolerances or Sensitivities

Food allergies vs. sensitivities

Food allergies can be defined as an abnormal reaction to food. This is caused by the immune system, which fights infection. It happens when the immune system mistakes a non-harmful food, like peanuts [tree nuts/shellfish/milk/soy/fish/eggs/wheat] for example, for a serious invader and overreacts to it. An IgE antibody is a compound that the immune system makes. It's responsible for most symptoms of allergies. These IgE-mediated allergic reactions may be mild or severe and even life-threatening.

Although allergies are most commonly noticed in childhood, they can also develop later in life and last a lifetime. Mild reactions to food allergies can lead to more severe symptoms when they are repeated. Even mild allergic reactions to food can lead to more severe symptoms the next time you eat it. It is important to talk to your healthcare provider if you have a reaction.

It is not clear where food allergies originate. Researchers have shown that food allergies can partly be genetic. Your gut microbiota could also play a role in your risk of developing food allergies. Recent studies have shown that peanuts introduced to young children may decrease their chance of developing severe peanut allergies. Before introducing peanuts to your child, talk with your healthcare provider.

Food allergies cannot be cured, but they can be avoided. An allergen in a food triggers the production of IgE antibodies. All foods can cause allergic reactions. However, there are a few foods that are most likely to trigger them. According to the FDA, these common food allergens should be listed on all package labels. Common food allergens include:


Tree nuts (e.g. almonds, walnuts and pecans).

Fish (e.g. cod, bass and flounder)

Shellfish (e.g. crab, lobster and shrimp)





Many food intolerances or sensitivities are mistakenly thought to be allergies. Although food intolerances may cause symptoms from eating certain foods, they are not caused by IgE antibodies. This is what makes them a sensitivity, not an allergy. FODMAP intolerance is due to 

Symptoms of food allergies

There are many types of food sensitivities and allergies. Here's a list of some of the most common reactions.

Anaphylaxis (or anaphylactic shock) 

Anaphylaxis (or anaphylactic shock) This is a fast and potentially life-threatening allergic reaction that can be caused by certain foods, medications or stinging insects (e.g. bees). Itching, itching, sneezing and coughing can all be symptoms. An anaphylactic reaction can be treated with an epinephrine self-injector or by calling 9-1-1. To avoid future, potentially life-threatening reactions, it is important to identify the cause of your reaction and prevent them from happening again.

Oral allergy or pollen-food allergy syndrome 

Oral allergy syndrome is when symptoms like rash, itching and sneezing occur around the mouth, lips and tongue. This syndrome is often associated with raw apples, cherries, bananas and melons. This allergic reaction isn't life-threatening, and it is common in people who are allergic to grass pollen and ragweed pollen. This type of allergic reaction is often reduced by cooking the vegetable or fruit. The heat damages the proteins that cause it.

Eosinophilic Esophagitis

Eosinophilic esophagitis may cause symptoms such as heartburn, nausea, vomiting, stomach pain, and difficulty swallowing after eating certain foods. It's important that you speak to your healthcare provider if this happens. It is important to avoid foods that can cause allergic reactions.

Symptoms of food sensitivities/intolerances 

Lactose intolerance

Lactose, a sugar found naturally in milk, can cause gas buildup in the digestive [digestive/GI] tract. This is not an allergy but an inability to digest the lactose. Lactose, a sugar molecule made up of two parts, requires the enzyme lactase for its breakdown. When someone does not have enough active lactase in their digestive [gastrointestinal/GI] tract, lactose remains intact and causes abdominal pain, nausea, excess gas, bloating, and diarrhea.

Gluten intolerance or Celiac Disease 

Gluten is a protein found naturally in wheat, rye and barley. Although intolerance to gluten is a condition of the immune system it is distinct from allergy by the specific antibodies involved. Allergies are caused by IgE antibodies while gluten intolerance is not.

Living with food allergies or intolerances

Avoiding foods that trigger reactions is the best way to manage food allergies. These are my top strategies for dealing with them.

  1. Pay attention to the labels on food. Pre-packaged foods should clearly indicate if they contain major food allergens or contain the immune-triggering proteins of major food allergens. This will help you avoid eating foods that cause allergic reactions. Check the ingredients list for allergen-free claims and statements such as "may contain" or “produced in a facility which also uses."
  2. To prevent cross-contamination of foods or other food, wash your hands and clean surfaces and utensils.
  3. Before ordering, verify that the restaurant is free of the allergens you are allergic to.
  4. Certain medications and cosmetics can also contain food allergens. Before you buy, make sure to read the labels carefully or consult your pharmacist.
  5. The FDA states that an anaphylactic reaction can occur if you have a known food allergy and begin to experience symptoms after eating.
  6. In case of anaphylactic reactions, you should always have an epinephrine self-injector on hand in case of accidental exposure. This lifesaving medication can keep your blood pressure stable and help you regain your ability to breath. Ask your pharmacist if a prescription is required. Make sure you know how to properly use it and that it is replaced as soon as it reaches its expiry date.
  7. Anaphylaxis can be a condition in which you might consider wearing a medical alert bracelet, or necklace.
  8. For lactose intolerance, all milk products can be consumed without restriction if they have the lactase inhibitor (available as a supplement to your diet) or are pre-treated with it (e.g. lactose-free dairy milk). These enzymes ensure that lactose is already broken down and will not cause intolerance symptoms.
  9. You should consult your healthcare provider if you suspect you might have a food allergy.



Food sensitivities and allergies are becoming more common. While both allergies and intolerances can cause unpleasant symptoms, food allergies can cause life threatening reactions. Avoiding the foods that cause allergic reactions or intolerances is a good idea. This article contains important tips for living with food allergies or sensitivities.

It is important to see your healthcare provider if you suspect you may have a severe food allergy. If you suspect you have FODMAP intolerance, we have several low FODMAP recipes/meal plans to help you.

Find customized low FODMAP meal plans  designed to help you enjoy the meals you love minus the foods that you may be sensitive to at



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MedlinePlus. (2020, September 28). Anaphylaxis. Retrieved from


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Medscape. (2020, February 5, 2020). Food Allergies. Retrieved from


National Institute of Allergy and Infectious Diseases. (2018, October 26). Identifying Food Allergy Causes and Assessing Prevention Strategies. Retrieved from


National Institute of Allergy and Infectious Diseases. (2019, September 11). Treatment for Food Allergy. Retrieved from


National Institute of Allergy and Infectious Diseases. (2018, October 25,). How to Characterize Food Allergy and Address Related Disorders. Retrieved from


NIH News in Health. (2017, March). Understanding Food Allergies. Retrieved from


United States Food and Drug Administration. (2018, September 26). What you need to know about food allergies Retrieved from

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