Diet is the primary source of pesticide exposure for much of the general public, but according to recent research at the UC Berkeley School of Public Health, exposure can be substantially reduced by opting for organic fruits and vegetables. A new study published in February Environmental Research found that families who switched to eating a completely organic diet had reduced traces of pesticides in their system by an average of 60 percent after just six days.
“There have been other organic diet intervention studies and our findings are consistent with those,” says Carly Hyland, a doctoral student in environmental health sciences at the UC Berkeley School of Public Health and lead author of this study.
According to Hyland, much of the research into organic diets has focused on organophosphate pesticides, but less is known about exposure and health effects of pyrethroids and neonicotinoids, which are increasing in use in conventional agriculture. In fact, neonics are the most widely used class of pesticides in the world, even though they’ve been shown to adversely affect wildlife like bees and other pollinators. Last year, the European Union banned the outdoor use of neonicotinoids, while American farmers widely apply them to major crops like corn and soybean.
In addition to organophosphates, this study looked at levels of pyrethroids, neonicotinoids, fungicides, and one herbicide.
With support from environmental group Friends of the Earth and the School of Public Health’s Center for Environmental Research and Children’s Health, or CERCH, Hyland enrolled four families across the United State —in Oakland, Atlanta, Baltimore, and Minneapolis—and measured their exposure to a range of common agricultural pesticides. Her research team collected urine samples for six days as the families ate a conventional diet and then again for another six days after these families switched to a 100 percent organic diet.
They found that the organic diet intervention made a dramatic difference. Pesticide levels in the urine dropped by up to 95 percent in some individuals after the six days. The most significant reductions were found for clothianidin, a neonicotinoid, and malathion and chlorpyrifos–both organophosphates.
The question still remains how low-level exposure to these pesticides affect human health. But growing evidence has revealed many of these chemicals as neurotoxic, particularly in the agricultural setting. One study at CERCH associated common organophosphates with decreased IQ’s among children in farmworker families in Salinas.
Hyland’s study did not focus on the health outcomes of pesticide exposure—only exposure levels. The research does, however, suggest two points: one, Americans ingest many different chemicals with untold health effects by eating conventionally-grown produce, and two, we have the ability to quickly rid our bodies of many of these pesticides simply by switching our diet.
Of course, the ability to switch to a fully organic diet isn’t accessible to many Americans. For the study, all organic foods for the six-day period were provided free of charge to the families and either delivered as groceries or prepared with all organic foods by a licensed chef or caterer and delivered to participants.
“We know that a lot of Americans, including myself, can’t afford all organic food,” Hyland says. “We don’t want the message from this study to be to stop eating fruits and vegetables.”
Hyland mentions that there are steps short of going all organic that can mitigate risk. For example, buying organic for members of the “Dirty Dozen” — the Environmental Working Group’s list of foods with the greatest pesticide residues, as opposed to its “Clean Fifteen.”
“Consumers are often inundated with headlines about all these harmful chemicals and don’t necessarily have ways to mitigate risk for common exposures,” says Hyland. “But this study provides the information that you can reduce your pesticide exposure.”
Study co-authors include researchers from the University of California at San Francisco, the Commonweal Institute in Bolinas, Friends of the Earth, as well as Asa Bradman and Bob Gunier from CERCH. Friends of the Earth funded the study.