A recent study has revealed that chemicals used to treat drinking water can cause food allergies in sensitive people.

Food allergies affect 15 million Americans and seem to be increasing further still. According to a study that was recently published in the Annals of Allergy, Asthma and Immunology – the scientific journal of the American College of Allergy, Asthma and Immunology (ACAAI) – chemicals used in pesticides and to purify municipal tap water may be the cause.

The study found that high concentrations of dichlorophenols in the human system was positively linked to food allergies.

“Our research shows that high levels of dichlorophenol-containing pesticides can possibly weaken food tolerance in some people, causing food allergy,” said allergist Elina Jerschow, M.D., M.Sc., ACAAI fellow and lead author of the study. “This chemical is commonly found in pesticides used by farmers and consumer insect and weed control products, as well as tap water.”

Of 10,348 people tested in a US National Health and Nutrition Examination Survey conducted during 2005-2006, 2,548 showed traces of dichlorophenols in their urine and 2,211 were monitored further for food allergies. Four hundred and eleven participants in the study suffered from a food allergy, while a further 1,016 participants exhibited an environmental allergy.

“Previous studies have shown that both food allergies and environmental pollution are increasing in the United States,” said Dr. Jerschow. “The results of our study suggest these two trends might be linked, and that increased use of pesticides and other chemicals is associated with a higher prevalence of food allergies.”

One way to reduce your exposure to these pollutants, and thus your risk of developing a food allergy, is to invest in a good quality water filter to remove pesticides and chemical contaminants from your drinking water, or opt for bottled water. However, according to this study, this may not always be enough.

“Other dichlorophenol sources, such as pesticide-treated fruits and vegetables, may play a greater role in causing food allergy,” explains Dr. Jerschow. According to the Centers for Disease Control and Prevention, there was an 18% increase in food allergies between 1997 and 2007, with milk, eggs, fish, shellfish, peanuts, tree nuts, wheat and soy being the most common food allergens.

Food allergy reactions can range from mild symptoms, such as a rash, to more severe reactions, such as anaphylaxis –where symptoms include swelling, difficulty breathing, and cardiac arrest, and thus can be life-threatening. The ACAAI recommends that anyone with a known food allergy should always carry two doses of epinephrine – a drug prescribed to counteract the effects of allergens. Failure to treat a severe allergic reaction with epinephrine in good time could result in cardiac arrest and death.

Visit the ACAAI website to learn more about food allergy and asthma relief or to find an allergist near you.

Journal Reference: Elina Jerschow, Aileen P. McGinn, Gabriele de Vos, Natalia Vernon, Sunit Jariwala, Golda Hudes, David Rosenstreich. Dichlorophenol-containing pesticides and allergies: results from the US National Health and Nutrition Examination Survey 2005-2006. Annals of Allergy, Asthma & Immunology, 2012; 109 (6): 420 DOI: 10.1016/j.anai.2012.09.005