15
Feb
Corroborating Earlier Studies, a Reduction in Pesticide Residues in Consumers Found after Switching to an Organic Diet
(Beyond Pesticides, February 15, 2019) A study, published in January 2019 in the journal Environmental Health, demonstrates that consumption of organic foods reduces significantly the levels of synthetic pesticide residues in the bodies of U.S. children and adults. Pesticide residues are found four times as frequently in conventionally grown food as in organically produced foodstuffs. Although the number of subjects in this study was relatively small, the results point to the importance of organics, and add to the evidence that organic food production and consumption are key to protecting human health.
Study subjects comprised members of racially diverse families — from Oakland, Minneapolis, Baltimore, and Atlanta — who did not typically consume an organic diet. Study participants, ages 4 to 52, ate their typical diet of conventionally grown foods for five days; for the following six days, they switched to a certified organic diet (provided by researchers) for consumption at home, work, school, or daycare, including all foods and beverages other than water. Urine samples were gathered prior to the “organic” days, and first thing on the morning after those six days. Fourteen different pesticides and metabolites were present in all participants’ urine in the “pre-organic” analysis; following the organic diet phase, all but one of the urinary levels of those pesticide biomarker compounds had dropped dramatically — by an average of more than 60%.
The study determines levels of residues on the basis of the presence, in excreted urine, of metabolites and parent compounds of neonicotinoids, organophosphates, pyrethroids, and 2,4-D. The most significant reductions are identified for the organophosphates malathion and chlorpyrifos, chemicals of urgent concern because of their extreme neurotoxicity, particularly for children. Some scientists have recommended a complete ban on the use of organophosphates, and Hawai’i became the first (and only) to ban chlorpyrifos in May, when the Governor signed a bill passed by the legislature the previous month.
Interestingly, given that neonicotinoids are the most widely used class of pesticides globally, of the two tested for in this investigation (clothianidin and a metabolite of imidacloprid), researchers detected the former in all samples, but the latter fell below the limit of detection in all samples. Study authors speculate that because imidacloprid is frequently found as a residue on food, it may be that this particular metabolite is not the best biomarker for evaluating dietary exposure to the compound. [Note: scientists at the U.S. Geological Survey (USGS) and the University of Iowa (UI) found drinking water contaminated with two neonicotinoid metabolites of imidacloprid that had not previously been identified in drinking water — desnitro-imidacloprid and imidacloprid-urea.]
Diet accounts for a considerable proportion of people’s exposures to pesticides in the U.S.; 2016 data from the United States Department of Agriculture (USDA) show that 47% of food produced domestically, and 49% of imported foods had detectable pesticide residues. Though there are some critical knowledge gaps (e.g., specific health outcomes associated with chronic dietary exposure to mixtures of pesticides), exposure to pesticide residues has been associated with a huge variety of health risks in people, including neurological and cognitive, developmental, reproductive, respiratory, and endocrine impacts.
Any number of studies point to organics as protective. The results of the subject study confirm, in part, those of earlier research on the matter, including: a 2014 investigation that identified reduced levels of urinary dialkyl phosphate (DAP), a metabolite of OPs, after a week-long shift to an organic diet; a 2015 study that found that adults who consumed organic produce had lower urinary levels of organophosphate residues (as detected via levels of DAPs); and another in 2015 that concluded that a switch to an organic diet reduced the body burden of pesticides in children, especially those in low-income urban, and in agricultural families.
The authors find that organic diet interventions cause significant reductions in all but one of the eighteen pesticide analytes tested. The largest reductions are in metabolites of the neurotoxic organophosphate insecticides malathion (95% ± 3%) and chlorpyrifos (60% ± 10%), and the systemic neonicotinoid clothianidin (83% ± 4). Authors highlight that neonicotinoid exposure is understudied, especially given its widespread and expanding usage and known toxic effects, and recommend that CDC take a lead role in including neonicotinoids in NHANES [National Health and Nutrition Examination Survey] testing. Organophosphates, on the other hand, have a long and well-known track record of chronic toxicity to humans.
Organophosphates (OPs) were originally developed by German scientists during World War II as the active agents in nerve gas. It is not surprising then that OPs, including malathion and chlorpyrifos, are recognized as the most toxic of all pesticides to humans and other vertebrates. Organophosphate exposure, even at low doses, has serious consequences for brain development and functioning. Long-term, low-dose exposure to OPs has been linked to neural and cognitive damage, learning disorders and neurological health problems, including Parkinson’s disease. Children are unacceptably threatened by continued OP use, as publicly recognized by EPA in 2016.
The study authors also report significant reductions in the herbicide 2,4-D and endocrine disrupting pyrehtroid metabolites 3PBA, FBPA, cDDCA and tDCCA among all participants. Interestingly, when researchers analyze data from adults and children separately, they find no significant drop in 3PBA and tDCCA among children following organic diet intervention. This suggests that children may face alternate exposure routes and/or have longer retention periods for pyrethroids, a factor that would further exacerbate chronic endocrine disruptor exposure during vulnerable periods of development.
These findings corroborate previous work showing that consumers take in significant and health-threatening levels of pesticides through conventional diets, and can dramatically reduce these intakes by switching to organic. A 2018 French research study of adults also found that higher frequency of organic food consumption — which is associated with lower pesticide exposure — was protective against several cancers. That investigation found that the most frequent consumers of organic food had 25% fewer cancers overall than those who never ate organic, and that those with the highest percentages of organic foods in their diet saw particularly large reductions in incidence of lymphomas, and significant reductions in postmenopausal breast cancers.
Research that has used an organic dietary “intervention” has seen, in some cases, startling degrees of reduction in post-protocol pesticide residues. In 2006, researchers noted that pesticide metabolites dropped to below detectable limits after an organic diet intervention and remained undetectable until a conventional diet was resumed. In a 2014 Australian study, a one-week organic diet protocol resulted in reductions of two pesticide metabolites by 89% and 96%, respectively. Taken together, all these research results suggest that there is greater dietary exposure to pesticides from conventionally produced foods than organic foods and that consumption of organic food significantly reduces this exposure.
Study co-author Kendra Klein, PhD, who is a senior staff scientist at Friends of the Earth (FOE), funder of this 2019 investigation, had this to say: “This study shows that organic works. We all have the right to food that is free of toxic pesticides. Farmers and farmworkers growing our nation’s food and rural communities have a right not to be exposed to chemicals linked to cancer, autism and infertility. And the way we grow food should protect, not harm, our environment. We urgently need our elected leaders to support our farmers in making healthy organic food available for all.” See the Friends of the Earth advocacy page here for more on the study and FOE’s “Organic for All” campaign.
If these consumer exposure findings seem alarming, what raises greater concern is farmworker and frontline community and children’s exposure to pesticides used in food production. While at least some consumers have a choice – though that too depends on neighborhood and income – farmworkers and communities living near conventionally managed farms, pesticide production plants, and waste management sites do not. See Eating with a Conscience.
Millions of Americans are faced daily with exposure levels to toxins that scientists and regulators are well aware cause lasting chronic damage to the brain and body. EPA has openly admitted that pesticide risks to agricultural workers, children and vulnerable populations exceed levels of concern.
Beyond Pesticides advocates for organic agriculture (as well as land management), for the benefits to human health, to the health of our environment (and both terrestrial and marine ecosystems), and to the Earth’s biota. Read more on the importance of organic, how to support it, and how to eat organically. Check out more resources here.
That “organic works” is surely good, if not new, news. As the Center for Food Safety has quipped, though in utter seriousness, “choosing organic foods isn’t a lifestyle, but a lifesaver.”
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: https://www.sciencedirect.com/science/article/pii/S0013935119300246#bib4
