DEAR MAYO CLINIC: I'm a grandmother to three wonderful grandchildren. My oldest grandchild is lactose intolerant. Recently, my youngest grandchild was diagnosed with a peanut allergy. What is the difference between food intolerance and allergy?
ANSWER: Life at the dinner table is different for thousands of people in the U.S. living with a food allergy. Recent studies show that approximately 5% of children under the age of 5 and 3% of adults have food allergies.
Food allergies and intolerances often are confused for one another. The symptoms can be similar.
If you have a food allergy, your body overreacts to a specific food as if it were a threat. This can occur when you ingest even the smallest amount of the food. For some people, the allergy may be triggered by smelling or coming into contact with the food.
When you come into contact with the food, your immune system releases an antibody called immunoglobulin E to neutralize the food allergen.
The immunoglobulin antibodies tell your immune system to release a chemical called histamine, which causes many allergic symptoms, such as itching, swelling, hives and difficulty breathing.
The top eight most common food allergens are egg, milk, peanuts, shellfish, tree nuts, soy, fish and wheat.
Unlike an allergic reaction, the symptoms of food intolerance are typically gastrointestinal. An intolerance means your body does not have the correct mechanisms to digest certain foods properly.
A common food intolerance is lactose — the main sugar in milk products. If you have lactose intolerance, your body has difficulty digesting lactose, causing symptoms of bloating, abdominal pain and sometimes diarrhea.
An allergist is the best qualified professional to diagnose a food allergy. Your allergist will begin by taking a detailed medical history to find out whether your symptoms are an allergic reaction, an intolerance or another health problem.
Unfortunately, those with food allergies cannot be cured. You can only prevent the symptoms by avoiding the foods that cause a reaction. If you come into contact with a food that causes a minor allergic reaction, you often can use an antihistamine to reduce the symptoms. For severe reactions, you may need an emergency epinephrine injection or a trip to the emergency department. You should always wear a medical alert bracelet or necklace. Seek medical care if you suspect you are having an allergic reaction. —Kjersten Nett, R.D.N., Clinical Nutrition, Mayo Clinic Health System, Albert Lea and Austin, Minnesota