By Lawrence LeBlond
Chlorine has long been added to tap water in many communities to ensure it is free of bugs and bacteria. The chemical is also found in many other household items, as well as in pesticides that are often used to treat produce.
New research from Albert Einstein College of Medicine in New York has now found evidence that the use of chlorine is associated with a rising number of people with food allergies.
Researchers found adults with high levels of dichlorophenol (a chemical by-product of chlorine) in their urine, were as much as 80 percent more likely to also have a food allergy. That’s a shocking find; especially when upwards of 15 million Americans suffer from food allergies.
Lead study author Elina Jerschow, assistant professor of allergy and immunology at Einstein, said the research “shows that high levels of dichlorophenol-containing pesticides can possibly weaken food tolerance in some people, causing food allergy.”
She noted that past studies “have shown that both food allergies and environmental pollution are increasing in the United States” and 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.”
As for chlorinated tap water, Jerschow said that switching to bottled water as a way to reduce the risk of developing a food allergy may not prove successful. “Other dichlorophenol sources, such as pesticide-treated fruits and vegetables, may play a greater role in causing food allergy,” she added.
Jerschow’s study looked at 10,348 participants in a US National Health and Nutrition Examination Survey (NHANES) from 2005-2006.
In that survey, 2,548 were found to have dichlorophenol measured in their urine, of which 2,211 were included in Jerschow’s study. In 411 of these participants, Jerschow and her colleagues found a food allergy. In another 1,016 participants, the team found evidence of an environmental allergy.
Those with the highest levels of dichlorophenol were 80 percent more likely to have an allergy to food—such as milk, eggs, peanuts or shrimp—than those with the lowest levels of the chemical.
“In this population, we found consistent associations between high levels of dichlorophenol exposure and a higher prevalence of food allergies,” the team wrote in their findings.
Among the group with the highest levels of the chemical—roughly 550 people—the chance of having both a food allergy and an environmental allergy was 61 percent higher than those with the lowest levels.
While the findings are surprising, Jerschow said further work is needed to “confirm” the association between dichlorophenol and allergy.
The Telegraph’s Stephen Adams, citing information from the World Health Organization (WHO), reported that there are currently no guidelines for dichlorophenol concentrations in water and other products because there only exists limited data on its toxicity.
The US Centers for Disease Control and Prevention (CDC) reports there was an 18 percent increase in food allergies seen between 1997 and 2007.
Previous studies have also shown that four percent of children have a food allergy. A rising number of children are diagnosed with gut allergies linked to common foods such as milk, soy, eggs, and a number of fruits and vegetables.
FOOD allergies can often involve a life-threatening reaction known as anaphylactic shock (or anaphylaxis), as well as eczema and rash. The American College of Allergy, Asthma and Immunology (ACAAI) advises everyone with a known food allergy to always carry two doses of allergist prescribed epinephrine. A delay in using epinephrine is common in severe food allergic reaction deaths.
The National Institute for Health and Clinical Excellence (NICE) estimated in 2010 that more than a third of people believe that they have some form of food allergy. However, only a tenth of those tested actually show signs of food allergy.
The findings of Jerschow’s study are published in the December issue of the Annals of Allergy, Asthma and Immunology, the scientific journal of the ACAAI.