Food Allergies: When Food Bites Back

We?re a population of sensitive eaters?it seems as if nearly everyone avoids one food or another because of some sort of intolerance. In fact, the Food Allergy & Anaphylaxis Network, an organization of health care professionals, government agencies and food industry members raising public awareness for food allergies, reports that food allergies afflict about 12 million people in the U.S.’that’s around 4 percent of the population. In addition to those with clinically-proven allergic responses to foods, another one out of three people believe they have a food allergy and, as a result, change the way they (or their family) eats. Unfortunately, many people avoid foods unnecessarily because of confusions surrounding food allergies, which can have a negative impact on a balanced diet.

How do you know if you have a true food allergy? Three official definitions can help clarify the topic of food allergies, according to Randy J. Horwitz, M.D., Ph.D., Medical Director of the Arizona Center for Integrative Medicine, who completed a fellowship in Allergy & Clinical Immunology at the University of Wisconsin and spoke at the Seventh Annual Nutrition and Health Conference in Atlanta on May 11, 2010. These are:

  • Adverse food reaction: any untoward reaction after the ingestion of a food; may be due to a food allergy or food intolerance.

  • Food allergy: an abnormal immunologic response following ingestion of a food.

  • Food intolerance: an adverse food reaction mediated by a non-immunologic mechanism.

An adverse food reaction is a generic term that lumps together any kind of negative reaction you get from eating a food, no matter what its cause. If you have a food allergy, your immune system decides that a particular food is harmful to your body, thus it creates specific antibodies to it. The next time you eat that food, the immune system releases large amounts of chemicals, including histamine, to protect your body. These chemicals trigger allergic symptoms that can affect the respiratory system, gastrointestinal tract, skin, or cardiovascular system. A classic example is a peanut allergy that might produce symptoms like swelling of the tongue and throat within a short period of time after consuming even a tiny amount of peanut. Unlike a food allergy, a food intolerance does not involve the immune system and is not life-threatening. A common example is lactose intolerance, difficulty in digesting milk sugar (lactose) that produces symptoms like abdominal cramps and diarrhea.

Food allergies on the rise. Data from a nationwide telephone survey on self-reported peanut and tree nut allergies’the leading cause of fatal allergic reactions in the U.S.?reveals that the prevalence of peanut allergy among children tripled between 1997 and 2008 (Journal of Allergy and Clinical Immunology, June, 2010.) This rate is similar to estimates in Canada, Australia and the U.K.

The researchers speculate that the rise in allergies could be linked to a number of factors, including the “hygiene hypothesis,” the idea that less exposure to allergens and bacteria in childhood leaves the immune system underdeveloped; or, the timing of when the food is introduced; or, how the food is prepared (i.e., cooking changes the nature of proteins in nuts.) Horwitz also reports that new evidence links antacids to the development of food allergies because they may interfere with digestion and allow food to enter the intestines before it is fully broken down, thus triggering an attack. No matter what the answer is, food allergies are a significant health problem and experts call for better medical treatment. The number of yearly emergency room visits due to food-induced anaphylaxis (severe, whole-body allergic reaction) in the U.S. is estimated at up to 125,000.

Digging for the truth. If you think you might have a food allergy, Horwitz suggests that your health care provider consider the following strategies:

  • Diet history. Keep a detailed diet diary recording foods eaten, timing of adverse reactions, and specific symptoms related to reactions.

  • Rule out non-immunity-mediated food intolerances. Conditions like celiac disease (a digestive disease caused by an immune response to gluten) may be mistaken for a food allergy.

  • Elimination diet. Short-term diet that removes one or more suspected foods from the diet to check for cause or elimination of symptoms.

  • Prick skin testing. Indicates presence of IgE (protein involved in food allergic reactions) antibodies specific to a particular food.

  • Double-blinded, placebo-controlled food challenge. Considered the “gold standard” of food allergy diagnoses; capsules or drinks with allergens (substances that cause allergic reaction) are provided to patients for observation in the doctor’s office.

  • RAST (radioallergosorbent test). Blood test done in laboratory with specific foods to determine whether there are IgE antibodies in that food.

Are there any interventions to treat food allergies other than avoidance of the food? Horwitz says that currently the answer is “no.” If you have food allergies, he recommends that you discuss an epinephrine autoinjector (EpiPen?) with your physician. Used to treat life-threatening allergic reactions, an EpiPen can be carried in your pocket or purse and is especially indicated if you have previously experienced anaphylaxis; have peanut, tree nut, fish or shellfish allergies; or have other conditions such as asthma. Living with a food allergy is a serious matter that requires serious care. ?Sharon Palmer, R.D.


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