Drinking Water Purifier Linked to Food Allergies; Solution Not in Bottles
According to the US Centers for Disease Control and Prevention (CDC), the number of people with food allergies is on the rise, particularly among children who live in urban areas. But the reason for the increase in cases is not entirely clear. Researchers are looking for environmental triggers and have found that a pesticide commonly used to treat drinking water may be involved.
The CDC notes that the prevalence of food allergy has increased in the US by 18% between 1997 and 2007. About 15 million Americans are affected. The most common food allergens are milk, eggs, peanuts, wheat, tree nuts, soy, fish and shellfish.
Allergist Elina Jerschow MD MSc, a fellow with the American College of Allergy, Asthma and Immunology (ACAAI), and colleagues evaluated data from the US National Health and Nutrition Examination Survey 2005-2006 which include responses from over 10,000 participants. In part, the study reported on more than 2,000 subjects who had substances known as dichlorophenols present in their urine. This chemical is used in pesticides and to chlorinate water.
Those with higher levels of the water-purifying pesticide were 80% more likely to have a food sensitivity than those with lower levels. They were also more likely to have environmental allergies, which are also known to be increasing in the US.
Dr. Jerschow suggests that dichlorophenols cause a decrease in exposure to bacteria that may have strengthened the immune system. “In an urbanized setting, we are not exposed to the same bacteria as we used to be,” says Dr. Jerschow. “For example, kids living on farms are exposed to more bacteria and have less allergies. It could be that dichlorophenols prevent us from being exposed to more bugs.”
While limiting our exposure to harmful bacteria is good in many ways – protecting us from deadly infectious diseases, for example - it can also have the effect of “misdirecting” the immune system, says Dr. Scott Sicherer, professor of pediatrics at the Jaffe Food Allergy Institute at Mount Sinai School of Medicine. He says that a misdirected immune system then looks for something else to fight, such as harmless invaders like food proteins, animal dander, or pollens.
But don’t be so quick to switch to bottled water based on this study, warns Dr. Jerschow. It’s important to understand that the study simply finds an association between dichlorophenol exposure and food allergies and does not establish a cause and effect relationship. Purified tap water may have other benefits to children, such as a source of fluoride which can prevent cavities.
However, more vigilance in protecting children from pesticide is not a bad idea. The American Academy of Pediatrics recently noted that exposure to these chemicals is more dangerous to children than adults, and diet is the most influential source of the toxins. Pesticides in foods have been linked to many conditions, including delayed mental development, insulin resistance, birth defects and some cancer.
1. 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