This article is more than 5 years old. Information may no longer be current.

Dichlorophenols found in pesticides, tap water may trigger food allergies

Dichlorophenol used in pesticides and chlorinated water may be partially responsible for the growing number of people in the United States affected by food allergies, according to recent study data.

Researchers analyzed data from the National Health and Nutrition Examination Survey 2005-2006, and measured two dichlorophenols — 2,4-dichlorophenol and 2,5-dichlorophenol — in their review. They determined exposure by questionnaires that asked participants about their use of pesticides applied in the last week to exterminate indoor insects or to control weeds. They also measured chlorinated phenol metabolites from participants’ urine samples.

Researchers learned that 2,548 participants (aged 6 years and older) of 10,438 people in the study had measurable dichlorophenols (greater than 0.14 mcg/L) in urine and allergen-specific serum IgE testing.

Dichlorophenol exposure was considered high when present in urine levels at the 75th percentile or above. Of 2,211 evaluable persons, 411 were sensitized to at least one food allergy, which was more pronounced when participants were exposed to two high dichlorophenol metabolites (adjusted OR=1.8; 95% CI, 1.2-2.5). At least one environmental allergy was found in 1,016 persons, but there was no significant association between exposure to two high dichlorophenols and sensitization to aeroallergens alone (aOR=0.96; 95%CI, 0.8-1.2).

Researchers said “wide consumption of bottled water in the United States may offset the importance of chlorinated water in supplying dichlorophenols to consumers,” but their presence may be attributed to other sources such as pesticide-treated fruits and vegetables.

“We found consistent associations between high levels of dichlorophenol exposure and a higher prevalence of food allergies,” the researchers concluded. “Previous research indicated that both environmental pollution and the prevalence of food allergies are increasing in the United States. The results of this study suggest that these [two] phenomena might be linked. Further prospective studies would be necessary to confirm this link.”