Allergic reactions caused by eating raw fruits and vegetables are referred to as oral allergy syndrome, or fruit-pollen syndrome. It is an immune response to proteins in some fruits and vegetables that are similar to some pollens. According to CNN Health, people's allergies to fruits and vegetables might diminish during seasons when pollen levels are low. This problem is typically a life-long battle, but you can avoid reactions by cooking, canning, microwaving, processing or baking offending fruits and vegetables.
Oral Allergy Syndrome
Anthony Ham Pong, M.B., B.S., a pediatric allergist in Ottawa, Ontario, says oral allergy syndrome occurs frequently during spring and late summer when hay fever is triggered by birch and ragweed pollens. The protein structures of tree, grass and weed pollens are similar to those in certain raw fruits and vegetables, Matthew Schulman writes in his U.S. News Health article "A Pesky Allergy to Fruits and Vegetables." The body's natural defense against allergens, immunoglobulin E, reacts to these foods in the same way it would an allergen. If you have oral allergy syndrome, you might react to some raw fruits, vegetables, seeds, spices and nuts. These foods can cause a reaction at any time, but can be worse during a particularly high-pollen season.
Symptoms
The website Calgary Allergy lists symptoms of fruit-pollen syndrome as itchy, tingly mouth, lips and throat. You might also experience itchy, watery eyes, a runny nose and sneezing. Severe symptoms are vomiting, cramps and diarrhea, while life-threatening reactions that require immediate medical attention include swelling of the throat, wheezing, difficulty breathing and anaphylaxis. The latter is characterized by a sudden drop in blood pressure and narrowing of the airway. Calgary Allergy notes that celery, kiwi, peaches, apricots, apples and nuts -- especially hazelnuts -- are the most likely to cause a severe reaction.
Pollens, Fruits and Vegetables
According to Schulman's article, if you have an allergy to birch pollen, you might react to apples, pears, peaches, plums, apricots, cherries, hazelnuts and kiwis. Warren Carr, an allergist in Mission Viejo, California, says anyone who is reactive to ragweed pollen is likely also allergic to watermelon, cantaloupe, zucchini and cucumber. And a weed mugwort allergy might cause problems for you with spices and vegetables in the parsley family like carrots, celery, dill and cumin. Grass allergy is akin to allergies to oranges, melons, watermelons, tomatoes, kiwis and peanuts. However, not all vegetables and fruits are ruled out by oral allergy syndrome. According to Carr, broccoli, cauliflower, lettuce, green onions and carrots are still on the menu, as well as citrus, tropical and berry fruits, as they rarely produce reactions.
Solutions
If you have a mild oral allergy, simply peeling an offending fruit might be enough to avoid a reaction, as most of the allergens are contained in the peel, Schulman writes. Ham Pong says microwaving fruits and vegetables for about 30 seconds will denature proteins in a fruit enough to allow a person with oral allergies to eat them. You might also cut fruits and vegetables and let them sit and oxidize before eating them. According to Ham Pong, this will release digestive enzymes that break down proteins. Allergen proteins are also broken down when cooked.
References
- CNN Health; Oral Allergy Syndrome May Explain Serious Reactions; Elizabeth Landau; 2008
- U.S. News Health; A Pesky Allergy to Fruits and Vegetables; Matthew Schulman; 2007
- MayoClinic.com; Anaphylaxis; Mayo Clinic staff; Sept. 2010
- Calgary Allergy Network; Oral Allergy Syndrome; Anthony Ham Pong, M.B., B.S; 2000
