Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, September 12, 1995 TAG: 9509120005
SECTION: EXTRA PAGE: 1 EDITION: METRO
SOURCE: JANE E. BRODY
DATELINE: LENGTH: Medium
These and other foods, in particular watermelon and honeydew, as well as a few plants like chrysanthemums and sunflowers, cross-react with ragweed and in some people can intensify the allergic response to the inhaled pollen.
Dr. Leonard Bielory, director of the Allergy and Asthma Research Center at the New Jersey Medical School in Newark, noted that three of four people with allergies were allergic to ragweed and, of those, 20 percent to 30 percent had a cross-reaction with chamomile.
The ragweed season extends in most parts of the country from August to November, peaking in mid- September. After that and until ragweed season returns next year, most people with ragweed allergy will be able to eat melons and bananas or drink chamomile tea without any problem.
Cross-reactions between well-known allergens and certain foods are more common than most people realize, Bielory said. ``Many people react to proteins that are found in all plants in the same family,'' he explained.
Unfortunately, some of these fundamental proteins are allergens, substances capable of setting off an allergic response in sensitive people.
For example, Dr. Dennis Ownby, an allergist at Henry Ford Hospital in Detroit, said that the protein profilin, which is involved with transporting substances in plants and animals, ``is presumably so important that it is widely shared throughout the plant kingdom.'' Profilin was first identified as an allergen in birch trees and has since been found in latex and in a number of weed pollens, he said.
Among the many clusters of food and pollen allergies are sensitivity to birch and mugwort pollen and allergy to celery, carrots, apples, potatoes, peaches and spices that belong to the Apiaceae family, namely anise, caraway, coriander, cumin, parsley and parsnip.
Another common cluster involves birch pollen and hazelnuts or peanuts or both. While the troublesome protein is destroyed when the food is cooked, other proteins in foods can cause an allergic reaction even when cooked.
Allergists have become especially concerned about the rising number of people who are allergic to latex. Allergy literature is full of reports of people with latex allergies who react to plant foods from a wide range of families: avocados, bananas, chestnuts, plums and peaches, potatoes and tomatoes and kiwi fruits.
Some also react to grass and ragweed pollens, melons, cucumbers and squash, while others have a cross-reacting allergy between latex and apricots, grapes, passion fruit, pineapple, figs, peaches and papaya.
``We rarely saw allergies to bananas or kiwis until latex allergy became more common,'' Ownby said. ``A sensitized person may eat a banana and her whole mouth will swell up.''
Dr. Yalamanchi K. Rao, an allergist affiliated with New York Methodist Hospital, noted that some of the newer fruit drinks ``like Snapple and Coca-Cola's Fruitopia contain many of these fruits mixed together in exotic cocktails'' and may aggravate a latex allergy in some people.
Also increasingly vexing are exercise-induced allergic reactions that are worsened by particular foods or simply by eating a meal of any type.
Dr. Richard Horan, an allergist affiliated with Brigham and Women's Hospital and Harvard Medical School in Boston, explained that allergic reactions induced by vigorous exercise could range from feelings of warmth and flushing to hives and itching palms, soles and mouth to wheezing, bronchial spasms, obstructed breathing and loss of consciousness.
``We have no idea why this happens, but we now know that in some patients it only happens if they exercise after eating a meal or consuming a particular food,'' Horan said. Among the foods, Rao listed apples, celery, peaches, cabbage, shrimp, oysters, clams and crabs.
The food must be consumed first. Exercise alone does not set off the reaction, nor does eating a culprit food or an entire meal after exercising have any ill effect in people with food-related allergies that are induced by exercise, Horan said.
He suggests that people with exercise-induced allergies remain alert to early warning signs and stop exercising when they feel symptoms.
``They will have a much milder reaction if they stop right away,'' he said. ``If they can identify factors that seem to trigger the allergic reaction - such as particular weather conditions, as well as eating a meal or certain foods beforehand - they would be wise to avoid those factors if they are planning to exercise soon after.''
Other precautions might include arranging to exercise with a friend and carrying a ``pen'' containing a dose of epinephrine that can be self-injected in case of a severe allergic reaction.
by CNB