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Food allergy vs. food intolerance: What's the difference?By Mayo Clinic staff
Original Article: http://www.mayoclinic.com/health/food-allergy/AN01109
- With Mayo Clinic asthma and allergy specialist
James T C Li, M.D., Ph.D.read biographyclose window
James T C Li, M.D., Ph.D.James Li, M.D.
"People with allergy or asthma can lead full and healthy lives." — Dr. James Li
Dr. James Li is chair of the Division of Allergic Diseases in the Department of Internal Medicine and a board-certified asthma and allergy specialist. He hopes his expertise and the information on the site educates health care consumers in an area of rapid change both in medications and diagnoses.
"There are a lot of misperceptions about allergy and asthma," says Dr. Li, a New York City native who has been with Mayo since 1985 and works with a group of subspecialists in allergy, asthma and immunology. "I believe it's important to provide truthful, accurate information about allergy and asthma to the public. The more people know, the better they can take care of these conditions."
Dr. Li is a professor of medicine at College of Medicine, Mayo Clinic. He's a past director of the American Academy of Allergy, Asthma & Immunology, the American Board of Allergy and Immunology, and the American Board of Internal Medicine. He's a fellow in the American College of Allergy, Asthma & Immunology.
The American College of Allergy, Asthma & Immunology honored him with the Distinguished Service Award, and the American Academy of Allergy, Asthma & Immunology with its Special Recognition Award.
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Food allergy vs. food intolerance: What's the difference?
What's the difference between a food intolerance and food allergy?
from James T C Li, M.D., Ph.D.
Food reactions are common, but most are caused by a food intolerance rather than a food allergy. A food intolerance can cause some of the same signs and symptoms as a food allergy, so people often confuse the two.
A true food allergy causes an immune system reaction that affects numerous organs in the body. It can cause a range of symptoms. In some cases, an allergic food reaction can be severe or life-threatening. In contrast, food intolerance symptoms are generally less serious and are limited to digestive problems.
If you have a food allergy, even a tiny amount of the offending food can cause an immediate, severe reaction. Digestive signs and symptoms may include nausea, vomiting, cramping and diarrhea. Other signs and symptoms can include a tingling mouth, hives, and swelling of the lips, face, tongue and throat. A life-threatening allergic reaction known as anaphylaxis can cause breathing trouble and dangerously low blood pressure. If you have a food allergy, you'll need to avoid the offending food entirely.
Food intolerance symptoms generally come on gradually and don't involve an immune system reaction. If you have a food intolerance, you may be able to eat small amounts of the offending food without trouble. You may also be able to take steps that help prevent a reaction. For example, if you have lactose intolerance, you may be able to drink lactose-free milk or take lactase enzyme pills that aid digestion (such as Lactaid).
Causes of food intolerance include:
- Absence of an enzyme needed to fully digest a food. Lactose intolerance is a common example.
- Irritable bowel syndrome. This chronic condition can cause cramping, constipation and diarrhea.
- Food poisoning. Toxins such as bacteria in spoiled food can cause severe digestive symptoms.
- Sensitivity to food additives. For example, sulfites used to preserve dried fruit, canned goods and wine can trigger asthma attacks in sensitive people.
- Recurring stress or psychological factors. Sometimes the mere thought of a food may make you sick. The reason is not fully understood.
- Celiac disease. Celiac disease has some features of a true food allergy because it does involve the immune system. However, symptoms are mostly gastrointestinal, and people with celiac disease are not at risk of anaphylaxis. This chronic digestive condition is triggered by eating gluten, a protein found in wheat and other grains.
If you have a reaction after eating a particular food, see your doctor to determine whether you have a food intolerance or a food allergy.
If you have a food allergy, you may be at risk of a life-threatening allergic reaction (anaphylaxis) — even if past reactions have been mild. Learn how to recognize a severe allergic reaction and know what to do if one occurs. You may need to carry an emergency epinephrine shot (EpiPen, Twinject) for emergency self-treatment.
If you have a food intolerance, your doctor may recommend steps to aid digestion of certain foods or to treat the underlying condition causing your reaction.Next question
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- Burks W. Clinical manifestations of food allergy: An overview. http://www.uptodate.com/home/index.html. Accessed March 16, 2011.
- Guidelines for the diagnosis and management of food allergy in the United States: Summary of the NIAID sponsored expert panel report. Bethesda, Md.: National Institute of Allergy and Infectious Diseases. http://www.niaid.nih.gov/topics/foodallergy/clinical/Pages/default.aspx. Accessed March 16, 2011.