Food allergies and food intolerances are two different conditions that are often confused with each other. Both can cause unpleasant symptoms, but they are caused by different mechanisms in the body.

Dr. Rebin Kader, an allergist/immunologist at the UCHealth Allergy and Immunology Clinic – Cherry Creek, answers questions about the difference between food allergy and food intolerance, what causes them, and how they can be managed.

What is a food allergy?

A food allergy is a condition in which the body’s immune system overreacts to a specific food. This immune system response is triggered by a protein in the food, which the body mistakenly identifies as a threat. When the immune system recognizes this protein, it releases chemicals such as histamine, which cause symptoms such as hives, swelling, and difficulty breathing.

Food allergies can be mild or severe, and in some cases, they can be life-threatening. The most common foods that cause allergies include milk, eggs, peanuts, tree nuts, fish, shellfish, soy, and wheat. In children, the most common food allergies are dairy products, eggs and peanuts.

What is food intolerance?

Food intolerance is a condition in which the body has difficulty digesting certain foods. Unlike food allergies, food intolerance does not involve the immune system. Instead, it is caused by a deficiency in enzymes or other substances needed to digest certain foods. This can lead to symptoms of food intolerance such as bloating, gas, diarrhea, and abdominal pain.

There are many different types of food intolerance, each caused by a different mechanism in the body. For example, lactose intolerance is caused by a deficiency in the enzyme lactase, which is needed to break down lactose (a sugar found in milk). Gluten intolerance is caused by a sensitivity to gluten, a protein found in wheat, barley, and rye.

What causes food allergy and food intolerance?

The causes of food allergy and food intolerance are different, but both conditions are influenced by genetic and environmental factors.

What causes food allergies?

The exact cause of food allergy is not well understood, but it is believed to be related to a combination of genetic and environmental factors. Certain people may be more genetically susceptible to food allergies, and exposure to allergenic foods at an early age may increase the risk of developing allergies later in life.

What causes food intolerance?

Food intolerance is caused by a deficiency in enzymes or other substances needed to digest certain foods. This deficiency may be genetic or acquired and can be influenced by factors such as age, diet, and the health of the digestive system.

How are food allergies and food intolerance diagnosed?

Food allergy and food intolerance are diagnosed through different methods.

Food allergy: Food allergy is diagnosed through a combination of medical history, physical examination, and allergy testing. Allergy testing may include skin tests or blood tests, which can identify specific IgE antibodies to specific foods.

Food intolerance: Food intolerance is diagnosed through a combination of medical history, physical examination, and diagnostic tests. Diagnostic tests may include lactose breath tests or blood tests for celiac disease, for example.

How are food allergy and food intolerance treated?

The treatment of food allergy and food intolerance depends on the severity of the condition.

Food Allergy: Treating food allergy involves strict avoidance of allergenic food. In cases of severe allergy, a prescription epinephrine auto-injector (like an EpiPen) may be prescribed for emergency use in case of accidental exposure. In some cases, oral immunotherapy may be recommended, which involves gradually increasing exposure to the allergenic food over time to desensitize the immune system.

Food intolerance: Treating food intolerance involves identifying and avoiding the foods that cause symptoms. In some cases, enzyme supplements may be recommended to help with digestion. For example, lactase supplements can be taken to help digest lactose in people with lactose intolerance.

Can food allergy and food intolerance be prevented?

Prevention of food allergy and food intolerance is not always possible, but there are some steps that can be taken to reduce the risk of developing these conditions.

Food allergy: Some studies suggest that early introduction of allergenic foods may actually reduce the risk of developing food allergies. However, this should only be done under the guidance of a healthcare professional. Breastfeeding may also help reduce the risk of developing allergies in infants.

Food intolerance: Some types of food intolerance, such as lactose intolerance, can be prevented by avoiding or limiting the intake of the offending food. In some cases, taking enzyme supplements may help with digestion.

What should I do if I suspect I have a food allergy or food intolerance?

Sometimes, people may self-diagnose a food allergy or food intolerance based on their symptoms. However, this can be dangerous as it may lead to unnecessary restrictions on the diet or the wrong treatment.

If you suspect that you have a food allergy or food intolerance, it is important to seek medical advice from a healthcare professional. A board-certified allergist/immunologist can help in identifying potential food allergies vs. food intolerance. They can perform a thorough review of the history of reactions to foods and diagnostic tests with advice on how to manage the condition.

By understanding the difference between food allergy and food intolerance, you can take steps to manage your symptoms and improve your quality of life.