by Marek M. Pienkowski, M.D., Ph.D.
The same foods, organic or not, may be perfectly nutritional for you but not for your neighbor. After just a single bite, some people develop severe reactions to foods. These reactions involve the immune system and specifically the allergenic antibody IgE. Symptoms may present in the digestive system, on the skin (hives); as swelling of the airways, or even loss of consciousness in the case of anaphylactic reaction.
Up to 30% of people think that they have food allergies; however, some 8% of children and 4% of adults suffer from true IgE-dependent food allergies. Others may have immunological reactions (IgG and IgA dependent), like Celiac disease or an enzyme deficiency (such as lactose or fructose), or food intolerance. These are both matters of concern, but unlikely life-threatening reactions.
Symptoms of food allergies can involve almost any organ in the body, and different foods may trigger different symptoms in the same individual.
Children typically develop eczema, abdominal pain, diarrhea, constipation, and reflux, which is associated with ear inflammation. Over time, untreated food allergies leading to the aforementioned symptoms may result in poor growth, irritability, and sleep disturbance.
In adults, symptoms may include hives, swelling of the lips or tongue, itching of the throat, eczema, nasal congestion and drainage, as well as shortness of breath and wheezing. In addition, abdominal pain, nausea, diarrhea, dizziness and fainting, and migraine headaches are common. Some people develop shock with light-headedness and loss of consciousness. Reactions that develop soon after exposure to allergenic food tend to be more dramatic.
“Symptoms of food allergies can involve almost any organ in the body, and different foods may trigger different symptoms in the same individual.”
Allergenic food typically triggers an allergic reaction in many food allergic individuals. However, some people might eat food to which they are allergic without noticing any symptoms. Some people may tolerate melons in the spring, but not in the fall, as melons share allergens with ragweed pollen, which is predominate in the fall. Other people may enjoy apples in the fall, but not in the spring, as birch pollen (prominent in the spring) cross reacts with apple allergens. Cooking food may make it less allergenic, but not always. Also, exercising prior to eating may precipitate itching and hives and even anaphylaxis (so-called exercise-induced food allergy) in some people.
Your risk of food allergies is high when you have hay fever or asthma. In addition, if a family member has food allergies, you are also more likely to have food allergies.
Food allergies decrease with age, so many infants or toddlers lose allergic reactions to milk, soy, eggs, or wheat. Unfortunately, allergies to tree nuts, peanuts and shellfish are likely to be persistent for life. Anyone with a persistent reaction to foods should seek medical attention, and especially those who experience an anaphylactic reaction.
Your allergy doctor will note a careful history of your reaction and the progression of your symptoms. Medical examination should reveal which organ system is involved. Your doctor will order a battery of tests, including skin tests for foods and, less commonly, blood tests. Further testing may involve a challenge test with the suspected food. A battery of blood tests may also be needed to assess other undetected medical conditions. Finally, you may be referred to a gastroenterologist.
The primary treatment for food allergies is avoidance of the offending foods, so proper identification and risk assessment is very important. Individuals with anaphylactic reactions (a loss of consciousness or swelling of the throat) will receive a self-injectable epinephrine kit prescription. For children or mentally impaired individuals, when avoidance (for example of peanuts) is almost impossible and the use of epinephrine is very difficult, they may undergo desensitization. Desensitization is a procedure that takes approximately 4-6 hours and effectively diminishes the chance of anaphylaxis. However, desensitizing an individual will require daily intake of a small amount of the offending food (like peanuts).
We anticipate the approval of anti IgE antibody (Xolair) for treatment of severe food allergies by the FDA in the not so distant future. Xolair has been shown in a number of research studies to effectively diminish the chances of anaphylaxis to a variety of foods. Other medications, such as antihistamines, steroids, and leukotriene inhibitors, have only limited value in attenuating symptoms.
Getting knowledgeable about your adverse reactions to foods will make healthy food truly good for your health.
Marek M. Pienkowski, M.D., Ph.D. was educated in clinical immunology at Johns Hopkins School of Medicine in Baltimore and internal medicine at Henry Ford Hospital in Detroit. Dr. Pienkowski has been serving patients in East Tennessee with allergies, asthma and immunological disorders for nearly 30 years through Allergic Diseases, Asthma & Immunology Clinic, P.C.. Active both in biomedical research and academia, he has published more than sixty scientific papers as well as two books.