Unpleasant reactions to food are not that unusual. But is the reaction an actual allergy, or an intolerance?
Food allergies affect about 2 to 4% of adults and less than 8% of children, while food intolerances are much more common. Other negative food reactions include food poisoning and food sensitivities. Together, they are widespread enough that nearly everyone is affected by at least one of them at some point.
A food allergy is an abnormal response to a food triggered by your body's immune system. In adults, the foods that most often trigger allergic reactions include: fish and shellfish, such as shrimp, lobster and crab; peanuts; tree nuts, such as walnuts; and eggs.
Allergies develop after you are exposed to a food protein that your body thinks is harmful. The first time you eat the food containing the protein, your immune system responds by creating specific disease-fighting IgE antibodies. When you eat the food again, it triggers the release of these IgE antibodies and other chemicals, including histamine, in an effort to get rid of the protein "invader."
As a result of this response, food allergy symptoms occur. The allergy symptoms you have depend on where in the body the histamine is released. If it is released in the ears, nose, and throat, you may have an itchy nose and mouth, or trouble breathing or swallowing. If histamine is released in the skin, you may develop hives or a rash. If histamine is released in the gastrointestinal tract, you likely will develop stomach pains, cramps, or diarrhea. Many people experience a combination of symptoms as the food is eaten and digested.
Anaphylaxis is the most extreme and life-threatening allergic reaction. It involves the whole body, including the airways, which can completely shut down. Tree nuts and peanuts are the leading food causes of anaphylaxis.
Food allergies often run in families, suggesting that the condition can be inherited, although family members may not be allergic to the same foods. And children may outgrow their allergies, while adults usually do not.
Food allergies can be triggered by even a small amount of the food and occur every time the food is consumed. People with food allergies are generally advised to avoid those foods completely.
Because food allergies involve an immune response, there is research that supports creating a strong and balanced immune system to provide some benefit to those with allergies. See Allergies: your immune System in Overdrive and Probiotics for Allergies?
Food intolerance and Sensitivities
Food intolerance also is an abnormal response to food, and its symptoms may be similar to those of food allergy. Food intolerance, however, is far more common, can be linked to a variety of diseases, and is not triggered by the same immune system reaction as a food allergy.
There are many factors that may contribute to food intolerance. In some cases, as with lactose intolerance, the person lacks the enzymes that are needed to properly digest certain proteins found in food. Lactose intolerance is the most common food intolerance, affecting about 10% of Americans.
People with food intolerance may not have symptoms unless they eat a large portion of the food or eat the food frequently. For example, a person with lactose intolerance may be able to drink milk in coffee or a single glass of milk, but becomes sick if he or she drinks several glasses of milk.
People who are lactose intolerant can actually become tolerant again by easing milk back into their diets. That's important, because eliminating dairy from your diet-even if you are intolerant-could be a bad nutritional decision, given all the benefits of low-fat dairy products. And even lactose-intolerant individuals can tolerate yogurt because its live cultures help maintain healthy levels of intestinal bacteria.
If the intolerance problem is due a lack of enzymes, supplementing with a broad range of enzymes may offer some relief. Digestion Support provides a digestive enzyme complex (including lactase, lipase, cellulase and protease) as well as herbs, fibers and probiotics to help digest food, eliminate waste, and create a healthy gut environment.
Also common are intolerances or sensitivities to chemical ingredients that are added to food to provide color, enhance taste, and protect against the growth of bacteria. These ingredients include various dyes and monosodium glutamate (MSG), a flavor enhancer.
Substances called sulfites are also a source of intolerance for some people. They may occur naturally, as in red wines or may be added to prevent the growth of mold. Other intolerance triggers include salicylates (found in aspirin), aspartame and caffeine.
Most food intolerances are found through trial and error to determine which food or foods cause symptoms. You may be asked to keep a food diary to record what you eat and when you get symptoms, and then look for common factors.
Another way to identify problem foods is to go on an elimination diet. This involves completely eliminating any suspect foods from your diet until you are symptom-free. You then begin to reintroduce the foods, one at a time. This can help you pinpoint which foods cause symptoms.
There are a number of other conditions or food reactions that can mimic food allergies. Here are a couple of the more common ones, all of which cause primarily a response in the digestive system:
• Irritable bowel syndrome. This chronic condition can cause cramping, constipation, gas and diarrhea. Many people find that their signs and symptoms worsen when they eat certain foods, and the possible role of food allergy or intolerance in irritable bowel syndrome has yet to be clearly understood.
• Celiac disease. A chronic digestive condition triggered by eating gluten, a protein found in foods containing wheat, barley or rye. Symptoms of celiac disease include diarrhea, abdominal pain and bloating. While celiac disease involves an immune system response, it's a more complex food reaction than a food allergy.
• Food poisoning. This illness generally results from spoiled or tainted food, it can cause severe digestive symptoms, and usually affects more than one person eating the food.
Your health care provider can help determine if you have a food allergy or intolerance, or one of the other conditions. If you have food allergies, you must identify and prevent them because, although usually mild and not severe, these reactions can cause devastating illness and, in rare instances, can be fatal.
An allergist/ immunologist is the best-qualified medical professional trained to manage the prevention, diagnosis and treatment of allergies. He or she will:
• Work to accurately diagnose your condition by taking a thorough patient history, including information about your symptoms, family history and home and work environment.
• Conduct allergy skin testing and any other needed tests.
• Help you develop an appropriate management plan, including treatment recommendations and advice on any needed environmental control measures.