Nutrition Column – Food Allergies: What You Should Know

Do you experience an unpleasant reaction, such as hives or nausea, when you eat certain foods? If so, you may have a food allergy. Then again, you may not. Despite the fact that millions of Americans believe they are allergic to one or more foods, fewer than 2 percent of adults suffer from true food allergies.

What is a food allergy? For people with true food allergies, the body’s immune system is unusually sensitive to a protein contained in particular foods. When a food containing the protein is eaten, the immune system produces antibodies to attack the foreign substance. The release of these antibodies triggers a chain reaction of chemical changes in the body, which in turn can cause uncomfortable and sometimes life-threatening symptoms.

Signs and symptoms: Different people experience different symptoms with food allergies. Most allergic responses occur within an hour of eating the offending food. Among the most common symptoms are swelling of the lips, mouth, tongue or face; hives; sneezing; and nausea. Other symptoms may include a rash, itchy skin, coughing or wheezing, abdominal pain or cramping, vomiting and diarrhea.

For most people, allergic reactions to food are uncomfortable but not dangerous. However, in rare instances an anaphylactic reaction occurs that can be life-threatening. Symptoms of an anaphylactic reaction often develop quickly and may include extreme itching, difficulty breathing, rapid heartbeat, low blood pressure and shock. Immediate medical attention is required for anyone experiencing an anaphylactic reaction.

Rooting out the cause: Certain foods seem to cause allergic reactions more frequently than others. Eggs, milk, wheat, soy, peanuts, tree nuts, shellfish and legumes are among the most common allergen-containing foods.

A medical evaluation is necessary to accurately diagnose a food allergy. During the evaluation, you likely will be asked about your symptoms – what are they, when and how often they appear, which foods and how much seem to cause the problem and whether you have a family history of food allergies. You also may be asked to complete a food diary about your eating and drinking habits and use of medication.

If your symptoms are not severe, you may be asked to try an elimination diet in which the food thought to be the culprit is avoided. If the symptoms disappear and then reappear when the food is eaten again, you have likely identified the food. Several medical tests also are available and may be used to help diagnose a food allergy including a skin-prick test and/or a blood test to check for signs of an immune reaction.

Dealing with a food allergy: Currently, there are no cures for food allergies. Your doctor may prescribe an antihistamine for annoying, but not severe, symptoms. For severe reactions, an injection of epinephrine (adrenaline) may be necessary. People prone to severe reactions to food are advised to wear a medical alert bracelet or necklace.

Once a food allergy is diagnosed, follow these steps to help prevent an allergic reaction:

  • Consult with your health care professional or a registered dietitian to learn how to manage your food allergy.
  • Always know what you are eating and drinking. Read food labels carefully.
  • Learn the common ingredient terms for the allergen. For example, if you are allergic to eggs, avoid foods that list albumin and globulin in the ingredient list.
  • When eating out, ask about ingredients and preparation methods of menu items before ordering.

Coming next week: An in-depth look at peanut and tree nut allergies.