Food allergens are foods that elicit a negative immune system response in the body. Though they affect a small percentage of the population, they may cause serious reactions. According to Mayo Clinic allergy specialist Dr. James T. Li, food allergies should not be confused with food sensitivities, which cause milder symptoms that do not affect the immune system. Once properly diagnosed, food allergy treatment generally involves avoidance of all allergen-containing foods.
Prevalence
Food allergies affect a small percentage of the population. According to the University of Maryland Medical Center (UMMC), roughly one-quarter of the U.S. population believe they have food allergies, but only 2 percent of adults and between 4 percent and 8 percent of children have been actually diagnosed with the condition. Most children with food allergies outgrow them by the time they reach adulthood.
Common Allergens and Foods
While any food can potentially cause allergic reactions, certain foods do so most frequently. According to the UMMC, roughly 90 percent of food allergies involve cow's milk, eggs, shellfish, peanuts, tree nuts, soy and wheat. Cow's milk is found in ice cream, cream, yogurt, cheese, baked goods and creamy dishes. Eggs are present in most mayonnaises, meringue, baked goods, soups, pastas and ice cream. Peanuts are common in peanut butter, nut mixes, candy bars and Thai dishes. Soy is found in edamame, miso soup, tofu, soy milk and many vegetarian meat alternatives. Shellfish include clams, mussels, oysters, crab and crayfish.
Symptoms
Food allergens produce various symptoms that range from mild to severe in intensity. According to Li, tightened airways, swollen throat, low blood pressure, rapid heart rate, dizziness and loss of consciousness may indicate a more severe reaction known as anaphylactic shock. Additional allergy symptoms may include skin rash, nausea, stomach pain, vomiting, swelling of the face or lips, and nasal congestion.
Risk Factors
Various factors contribute to whether a person develops food allergies. According to the UMMC, a family history of allergies increases a person's risk of developing similar allergies. When one parent has food allergies, children have a 30 percent to 40 percent chance of developing them. The risk increases to 75 percent if both parents have food allergies. Culture also plays a role, as over-exposure to particular foods can cause allergies. For example, Japanese residents are more likely to develop an allergy to rice than people in countries where rice is not a staple.
Treatment
Treatment for food allergies generally involves avoidance of food allergens, particularly for people at risk for severe allergic reactions. According to the UMMC, antihistamine medications are effective in reducing itching, swelling, skin rash, headache and runny nose. Injections of epinephrine, also known as adrenaline, are used to avert anaphylactic shock.
Suggestions
Because many self-perceived food allergies are not allergies at all, and because allergic reactions are often serious, proper testing is suggested when an allergy is suspected. According to the UMMC, doctors review information regarding family and personal medical history, observed symptoms, frequency and severity of symptoms and which foods tend to trigger reactions. For this reason, a detailed log that includes times, dates and observations may prove useful. Because allergies may be genetic, the UMMC suggests restricting common food allergens from an infant's diet if one or both parents have food allergies until the infant is old enough to be tested.
