A chemical used in tap water chlorination and pesticides for produce has been associated with increased risk of food allergies, according to a new study in the journal Annals of Allergy, Asthma and Immunology.
Researchers found that people with the highest levels of dichlorophenols in their urine also have higher odds of having a food allergy.
However, the researchers cautioned that the findings don't mean that people should stop drinking tap water so that they don't have dichlorophenols in their systems -- rather, the dichlorophenols probably come from pesticide-treated fruits and vegetables.
The findings are based on 10,348 people who participated in the U.S. National Health and Nutrition Examination Survey between 2005 and 2006. Of those people, 2,548 had detectable levels of dichlorophenols in their urine, and of those people, 2,211 were actually used for the study.
Of those 2,211 people, 411 had food allergies, while 1,016 of them had some sort of environmental allergy, researchers found.
"High urine levels of dichlorophenols are associated with the presence of sensitization to foods in a US population," the researchers wrote. "Excessive use of dichlorophenols may contribute to the increasing incidence of food allergies in westernized societies."
Because the study only found an association -- not a cause-and-effect phenomenon -- it's hard to say what exactly it is about dichlorophenols that could spur allergies, if they do at all. But "while the study does not allow concluding that pesticides are responsible for the allergies, it certainly raises the possibility and justifies pursuing the kinds of studies that can help sort of if these pesticides are, indeed, the cause," Dr. Kenneth Spaeth, director of the Occupational and Environmental Medicine Center at North Shore University Hospital, who was not involved in the study, told ABC News.