The difference between a food allergy and intolerance is how your body responds to a foreign trigger. The immune system causes an allergic reaction, while your digestive system causes an intolerance.

The terms “allergy” and “intolerance” both refer to the body’s reaction to a foreign substance.

However, food allergies and intolerances are not the same.

Keep reading to learn more about the different causes, symptoms, and treatments of food allergies and intolerances.

Food intolerance is when your gut has difficulty processing or digesting certain foods. It’s estimated that food intolerances affect up to 20% of the population.


Food intolerances are not typically life threatening, according to Allergy UK. However, they may cause a range of discomforting, digestive-related symptoms, including:

  • gas
  • bloating
  • diarrhea
  • constipation
  • cramping
  • stomach pain
  • fatigue
  • nausea


Food intolerances happen when your body can’t properly break down a certain substance in your digestive tract. It’s usually caused by not having enough of a certain digestive enzyme, or pharmacological factors like sensitivities to certain foods.

Some common types of food intolerances include:

  • Lactose: This is a type of sugar found in dairy products like cow’s milk, cheese, and yogurt. Lactose intolerance is caused by a shortage of lactase enzymes, which help break down lactose in your gut.
  • Histamine: This is a chemical found in preserved, processed, or fermented foods. It’s broken down in your digestive tract by the enzymes diamine oxidase and histamine-N-methyltransferase. If these are impaired, high levels of histamine can accumulate in your body.
  • Gluten: This is a group of proteins found in grains like wheat, barley, and rye. Non-celiac gluten sensitivity is when you experience symptoms after eating gluten but haven’t received a diagnosis of celiac disease, an autoimmune condition.
  • Sulfites: These chemicals are common food preservatives. They may cause food intolerance symptoms in people with asthma, according to Allergy UK.

Your immune system is your body’s defense against invaders like bacteria, viruses, and fungi. Food allergies happen when your immune system identifies an invader in something you eat and reacts by producing antibodies to fight it.

Approximately 8% of children and 11% of adults in the United States have a food allergy, according to the National Institute of Allergy and Infectious Diseases.


Food allergies may cause symptoms that can range from mild to life threatening. These may include:

  • dizziness
  • hives, rash, or itchy skin
  • swelling in your face, lips, or eyes
  • coughing
  • shortness of breath
  • wheezing
  • sneezing
  • stomach pain
  • diarrhea

Is my allergic reaction an emergency?

Anaphylaxis is a severe, life threatening reaction to an allergen. It’s critical to get immediate medical attention if you experience any of the following symptoms after eating food:

  • sudden swelling of the mouth, lips, throat, or tongue
  • sudden rash
  • shortness of breath, wheezing, or gasping for air
  • very fast, rapid breathing
  • difficulty swallowing
  • sudden dizziness
  • skin, tongue, or lips becoming blue or pale
  • unresponsiveness, such as difficulty raising your head
  • fainting
  • unconsciousness
Was this helpful?


A food allergy happens when your immune system attacks a food protein because it thinks it’s threatening.

Your immune system does this by creating antibodies to fight the invader. The most common antibodies are immunoglobulin E (IgE). These may cause an immediate reaction when they release defensive chemicals, such as histamine.

Food allergies can be fatal, unlike food intolerances. In extreme cases, ingesting or even touching a small amount of the allergen can cause a severe reaction, known as anaphylaxis. This happens when your immune system overreacts, releasing high amounts of histamine into your body.

According to the U.S. Food and Drug Administration, the following nine foods account for 90% of allergic reactions:

  • milk
  • eggs
  • fish
  • shellfish
  • peanuts
  • tree nuts
  • wheat
  • soybeans
  • sesame

There are also non-IGE-mediated food allergies. These occur when other cells in your immune system are activated.

Symptoms of non-IGE reactions primarily affect your skin and gastrointestinal tract. These may include vomiting, bloating, or eczema. Less is known about this particular type of reaction. However, it’s usually not life threatening.

There’s no cure for food intolerances or allergies. However, a healthcare professional may recommend a management plan to provide symptom relief and prevent a reaction. This may include:

  • avoiding foods that trigger a reaction
  • taking over-the-counter or prescription medications, such as antihistamines or topical creams
  • using an emergency autoinjector (EpiPen) if you’re experiencing anaphylaxis
  • immunotherapy to help lessen the severity of reactions

If you or someone you’re with experiences anaphylaxis after eating food, get immediate medical attention.

The National Health Service (NHS) recommends taking the following steps:

  1. Use an adrenaline auto-injector, such as EpiPen, if you have one. Make sure to follow the instructions as described on the injector.
  2. Call 911 or your local emergency phone number. Tell them you or someone you’re with is experiencing an anaphylactic shock.
  3. Lie down on the back and lift the legs and shoulders.
  4. Use a second adrenaline auto-injector if symptoms haven’t improved after 5 minutes.

If your child has a food allergy, you must know how to treat accidental food ingestions. A self-injectable epinephrine must always be available.

The potential effects of an allergic reaction are severe. But, efforts are made to accommodate people with food allergies. For example, school lunchrooms may be peanut-free to cater to children with peanut allergies.

Also, product labels must state if a food is made in the same facility that processes the most common allergens.

Is a food sensitivity the same as an allergy?

Food sensitivity is a term that refers to a range of symptoms that arise from an immune system reaction to food. These reactions are typically less severe than allergic reactions. However, there’s no clear definition of food sensitivity.

Can you be sensitive to food but not allergic?

Yes. Eating certain types of food may trigger digestive-related symptoms, such as bloating. These are not allergic reactions, but food intolerance symptoms can be very uncomfortable.

What are the 3 signs of food intolerance?

Symptoms of food intolerance typically affect your digestive system. These may include diarrhea, bloating, and stomach pain, among others.

What are the 3 most common food intolerances?

According to a 2021 review, the three most common food intolerances include lactose, gluten, and histamine.

Food intolerances and allergies can both cause symptoms. However, they’re both different types of reactions.

It’s important to avoid triggering foods that may cause a reaction, especially if it’s an allergen. In some cases, food allergies may lead to anaphylaxis, which can be life threatening.