Understanding Food Allergies

Did you know that approximately 200 Americans die each year from food-induced anaphylaxis, a severe and potentially fatal systemic allergic response (Sampson 2002)? Some 30,000 adults and children end up in U.S emergency departments suffering from an anaphylactic reaction to food (Food Allergy & Anaphylaxis Network [FAAN] 2006a). And you don’t have to pig out to be a victim of a food allergy. Sometimes, exposure to even a miniscule amount of an allergen can be extremely harmful.

For reasons not yet fully understood, food allergies appear to be on the rise. In the United States, up to 8% of children and 2% of adults now suffer from them (U.S. Department of Health and Human Services [DHHS] 2004). While much more common in children than adults, allergies affect people of all ages and ethnicities.

Chances are, at some point in your wellness career, you will encounter a client, friend or family member who is allergic to a particular food. When that happens, it will be important to recognize the most common food allergies, what causes them, how to identify them, and what people with allergies (and their parents, in the case of children) can do to avoid experiencing their harmful symptoms.

Understanding Food Allergies
The 8 most common food allergens, which account for 90% of all allergic reactions, are milk, eggs, peanuts, tree nuts (such as almonds, cashews and walnuts), shellfish, fish, soy and wheat (Mayo Clinic 2006).

The proteins in these foods cause millions of people to itch, break out in hives and sometimes go into anaphylactic shock, a life-threatening situation. This anaphylactic reaction occurs because the body misinterprets the food as an invader. When the perceived “invader” enters the bloodstream, the immune system creates an antibody called immunoglobulin E, or IgE, to kill and destroy the interloper.

With repeat exposure to the food, the antibody responds by binding to the allergen. This sets in motion a series of immunologic events, including the release of the hormone called histamine. Histamine is responsible for many food allergy symptoms, which include redness, swelling, itching, gastrointestinal symptoms and hypotension.

Once the body creates an antibody to a food, an immune response ensues every time that food is eaten. In rare but deadly cases, the heart rate drops, the breathing tubes narrow and the tongue swells, making breathing and adequate oxygenation to the body’s cells a struggle. The harmful response can occur from minutes to an hour after the food is eaten (DHHS 2004).

Fishing for Red Herrings
When symptoms first appear, it’s important to differentiate between a real food allergy and another potential cause. Often, the cause of the ailment is something else, such as food poisoning, a nonfood allergen (such as pollen, dust or dander) or ─ most commonly ─ a food intolerance.

While food allergies and food intolerances both result from the body’s inability to handle specific foods, the mechanisms at play that cause the symptoms are quite different. A food intolerance results from a deficiency in an enzyme needed to break down a food. For example, lactose intolerance results from a deficiency in the enzyme lactase, necessary to digest the sugar. Undigested lactose can cause gastrointestinal symptoms, such as abdominal pain, bloating and diarrhea. Unlike with a food allergy, the immune system plays no role in the dysfunction (DHHS 2004), and the uncomfortable symptoms are not life threatening.

Proper Handling of Clients With Food Allergies
Clearly, rapid treatment is critical for any client showing the symptoms of a severe allergic reaction, such as dizziness, wheezing, falling blood pressure or difficulty breathing. Emergency medical services should be contacted to transport the client to the hospital (in mild cases, you can drive the person to a local emergency room). Medical treatment may involve injectable epinephrine, antihistamines and other emergency measures (American Academy of Allergy, Asthma & Immunology [AAAI] 2006). These medicines reverse the allergic response by restoring blood pressure, blocking further production of histamine and countering the harmful effects induced by the allergen.

After treatment of acute symptoms of an allergic reaction, the client will need to be referred to an allergist, who will try to identify the food culprit. This step can be either a simple process or an arduous, time-consuming journey. The physician’s first objective will be to get a complete history of the reaction, including onset and duration, symptoms, seasonality, suspect foods, how the foods were prepared and any other information the patient can provide. A complete physical exam will follow, to gather as much information about the reaction as possible. In most cases, this comprehensive assessment will reveal a few suspect foods.

Usually the next step for the client (but not for one who has had a severe reaction!) is to keep a food diary, to document all foods eaten and any allergic reactions. If a potential allergen is noted, it is then removed from the diet and the client continues to keep the food diary. If the symptoms disappear after a suspect food is eliminated from the diet, the diagnosis is fairly obvious, and the patient should strive to avoid the offender.

If, however, the diagnosis remains uncertain, the allergist can do a scratch skin test. With this test, a small amount of the food is placed on the skin of the lower arm, which is then checked for redness and swelling. If the test is positive for a particular food, the diagnosis is confirmed. Another test option is the gold standard for food allergy diagnosis: the double-blind food challenge. The patient swallows a series of capsules that contain different common food allergens and is then watched to see if symptoms occur. Neither the patient nor the physician knows which food is in which capsule (the capsules are prepared by a third party). Unfortunately, this test is time-consuming and impractical for many allergens and, as such, is rarely performed.

Of course, all these tests could be deadly for people with severe allergic reactions. For these individuals, diagnosis is made with a blood test that measures the presence of a food-specific antibody (DHHS 2004).

Where You Can Help
As a wellness professional, you regularly update your CPR and first-aid certifications so that you’ll be prepared to help clients in case of an emergency. While food allergy management probably hasn’t been on your radar, it should be! This is especially true if you work with children and teens or if you train anyone susceptible to an exercise-induced or typical food allergy. Before you know it, you may be faced with the task of recognizing and responding to anaphylaxis or some other severe allergic reaction in a client. If you are prepared and think fast, you could save someone’s life.

References
American Academy of Allergy, Asthma & Immunology (AAAID). 2006. Tips to remember: Food allergy. www.aaaai.org/patients/publicedmat/tips/foodallergy.stm; retrieved May 16, 2006.
Food Allergy & Anaphylaxis Network (FAAN). 2006a. Press release: Avoiding food allergens is a formidable task. www.foodallergy.org/press_releases/avoidingfoodallergens.html; retrieved May 16, 2006.
Food Allergy & Anaphylaxis Network (FAAN). 2006b. FAAN to discuss risk-taking and coping strategies of teens with food allergies at the AAAAI annual conference. Medicalnewstoday.com; retrieved May 17, 2006.
Food Allergy & Anaphylaxis Network (FAAN). 2006c. Talking to your teen about food allergy. www.foodallergy.org/downloads/teenbrochure.pdf; retrieved May 17, 2006.
KidsHealth. 2005. Food allergies. http://www.kidshealth.org; retrieved May 17, 2006.
Mayo Clinic. 2006. Food allergies: New food-labeling requirements. www.mayoclinic.com/health/food-allergies/AA00057; retrieved May 16, 2006.
Sampson, H. 2002. Peanut allergy. New England Journal of Medicine, 346 (17), 1294-99.
U.S. Department of Health and Human Services (DHHS). 2004. National Institutes of Health, National Institute of Allergy and Infectious Disease: NIH Publication No. 04-5518. www.niaid.nih.gov/publications/pdf/foodallergy.pdf; retrieved May 16, 2006.