Food allergies are tough enough when you know what not to eat to avoid a reaction. But while some triggers are obvious—if you’re allergic to eggs, for instance, you don’t want to be ordering any omelets—others aren’t as apparent. And even if you don’t have an existing allergy, exposure to some substances could trigger one. Something as simple as the water you drink could spark a reaction. We asked top allergy specialists to clue us in to some of the more surprising triggers to watch out for.
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Pesticides and possibly chlorinated water. A 2012 study at the Albert Einstein College of Medicine/Montefiore Medical Center in the Bronx found that people with high urine levels of chemicals called dichlorophenols were also more likely to be allergic to at least one of the following: peanuts, eggs, milk or shrimp (the only food allergens tested). Dichlorophenols are commonly used in pesticides and are also by-products that appear in chlorinated water.
“You are 80 percent more like to have one of those food allergies if you have been exposed to dichlorophenols,” says study author Dr. Elina Jerschow, assistant professor of medicine and attending physician for pediatric and adult allergy and immunology at Einstein/Montefiore. Although the mechanism by which dichlorophenols affect sensitization to foods is unclear, Jerschow speculates that ongoing exposure could weaken a person’s tolerance to certain foods, perhaps by affecting bacterial diversity in the gut. She notes that great effort is used to minimize dichlorophenols in chlorinated water, and it’s unclear if bottled water is any safer. However, mineral water does not contain the chemical, says Nsouli.
The more likely source of exposure is pesticides. “It’s premature to suggest that you avoid anything at this point,” says Jerschow, “except that not eating [foods with] pesticides is probably healthier than eating them.”
Hidden foods. “Let’s say you’re allergic to chicken, and chicken was cooked on the same pan later used for your fish. Part of the fish in the pan may then be contaminated,” says Dr. Sami Bahna, past president of the American College of Allergy, Asthma and Immunology, and chief of the Allergy/Immunology Section at Louisiana State University School of Medicine in Shreveport, La.
“If you go to a restaurant or somewhere to eat, mention to the waiter or chef whatever you are extremely allergic to,” suggests Dr. Talal Nsouli, board member and fellow of the American College of Allergy, Asthma and Immunology, and professor of pediatrics and allergy immunology at Georgetown University School of Medicine. “Double check that there is no contamination.”
Unidentified additives. “Certain restaurants and manufacturers add additives for coloring, texture and taste, and like to keep them secret to maintain a competitive edge,” Bahna says . Despite U.S. Food and Drug Administration pressure, manufacturers still keep ingredients lists vague, writing “natural coloring” or “spices” without truly identifying what they are. “Call the manufacturing company, telling it that you suspect you are allergic to one of the ingredients and ask for a list of ingredients,” suggests Nsouli. You can also buy foods from companies that specialize in allergen-free foods such as Ener-G.
Certain medications. “Medications, particularly creams, lotions and ointments may have animal or plant proteins that people with food allergies react to,” says Bahna. Again, call the manufacturer to get a complete list of ingredients.
Cross-reacting foods. “A person may be allergic to latex, and then react to foods that have proteins similar to latex,” says Bahna. According to the American Latex Allergy Association, foods most likely to cause a cross-reaction are avocado, banana, chestnut and kiwi. If you’re allergic to latex, you can also have a reaction to foods handled by someone wearing latex gloves. For more information on foods that may contain these proteins, go to the American Latex Allergy Association website.
Sunlight. Odd as it sounds, if your skin has touched herbs and foods such as parsley and parsnip, and that part of your skin is exposed to sunlight, your skin may become irritated and red a day or two after exposure, says Bahna. The reaction—not a true allergic reaction—subsides in several days.
Pollens. You may think you’re allergic to some spices when in fact, you’re reacting to mugwort, a weedy herb native to North America, and birch pollen that can cause a cross-reaction to some spices, including coriander, fennel, parsley and caraway. To help figure out your reactions, Bahna suggests keeping a diary, recording food and circumstances surrounding your symptoms.
Simply smelling. You don’t have to eat a food to have an allergic reaction to it, says Bahna. Particles of a food can be released into the air that you inhale and react to. “But this is not frequent,” says Nsouli. “It usually happens in a enclosed area like a plane or small room.” Most important is to have injectable epinephrine, a hormone that controls severe allergic reactions, and to know how to use it. According to Nsouli, 72 percent of people with life-threatening food allergies do not. Nsouli recommends a newly approved FDA device, Auvi-Q, that comes with voice instructions.