Study Links Produce Consumption to Pesticide Levels
A new peer-reviewed study by scientists at the Environmental Working Group (EWG) suggests that consuming certain fruits and vegetables may increase pesticide chemical levels in the human body. Pesticides have been associated with health issues, including cancer, reproductive problems, hormone interference, and nervous system harm in children. Traces of these chemicals are frequently detected on produce, leading to potential dietary exposure. Researchers indicate these findings could inform future studies on long-term dietary pesticide exposure and human health.
"Our findings indicate that dietary intake directly influences pesticide levels in the body. While consuming produce is essential for a healthy diet, it can also elevate pesticide exposure."
– Alexis Temkin, Ph.D., vice president for science at EWG and lead author.
Higher Residue Produce Correlates with Increased Pesticide Levels
Individuals who reported consuming larger quantities of fruits and vegetables known to contain higher pesticide residues, such as strawberries, spinach, and bell peppers, showed significantly higher pesticide levels in their urine compared to those primarily consuming lower residue produce. These results suggest diet as a key factor in pesticide exposure and provide a basis for investigating potential long-term health effects.
This study expands on previous research indicating that specific fruits and vegetables are a notable source of pesticide exposure for many Americans. Young children and pregnant individuals are particularly susceptible to potential harm from exposure.
Methodology for Measuring Dietary Pesticide Exposure
The study was published in the International Journal of Hygiene and Environmental Health.
EWG researchers analyzed U.S. Department of Agriculture (USDA) data on pesticide residues in produce collected between 2013 and 2018. This data was combined with dietary survey responses and urine biomonitoring data from 1,837 participants in the Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey (NHANES) from 2015 to 2016. These datasets represent the most recent years with extensive pesticide tracking, with NHANES biomonitoring data currently available through 2018.
Scientists developed a "dietary pesticide exposure score" to estimate an individual's exposure. This score was based on consumed fruit and vegetable types, residue levels detected, frequency of specific pesticide detection, detected amounts, and the relative toxicity of each chemical.
These exposure scores were then compared with 15 pesticide biomarkers measured in participants' urine, representing three main pesticide categories: organophosphates, pyrethroids, and neonicotinoids. The analysis demonstrated a strong association between the types of produce consumed and the levels of pesticide biomarkers in urine, indicating that pesticide exposure varies based on dietary choices and residue levels on foods.
Key Findings on Diet and Pesticide Mixtures
The study confirmed the link between higher residue produce and increased pesticide levels in the body and identified several patterns:
- Diet's Role: Individuals consuming more produce with high pesticide residues were more likely to have those chemicals detected in their urine compared to those choosing lower residue options.
- Monitoring Gaps: NHANES monitors only a fraction of the pesticides found on food and examined in this research, suggesting a need for broader monitoring due to exposure to many different agricultural chemicals.
- Mixture Exposure: USDA-tested fruits and vegetables contained measurable residues of 178 different pesticides; however, only 42 of these chemicals corresponded to biomarkers measured in urine samples, suggesting that total exposure may be more extensive than current biomonitoring captures.
- Potatoes' Influence: The correlation between produce intake and pesticide levels became clear after potatoes were removed from the dataset. Estimating pesticide exposure from potatoes is complex due to various consumption forms, indicating a need for additional research.
Implications for Pesticide Regulations
Previous research on pesticide exposure primarily focused on farm workers or residential use. This study indicates that daily food choices can also contribute significantly to pesticide exposure among the general public.
Given the observed widespread exposure, the findings prompt questions regarding whether current safety standards set by the Environmental Protection Agency (EPA) adequately protect public health. The EPA typically establishes limits for individual pesticides, which do not account for cumulative exposure to multiple pesticide residues commonly found together on USDA-tested produce.
The researchers suggest their exposure scoring method could assist regulators and scientists in better evaluating real-world dietary exposure and improving protections for vulnerable groups, particularly children and pregnant individuals.
"The study's reliance on robust federal data emphasizes the importance of strong public health agencies for policymakers. Pesticide residue tests and CDC biomonitoring data represent essential research that government agencies are uniquely positioned to provide."
– Varun Subramaniam, EWG science analyst.
Consumer Recommendations from EWG
EWG continues to recommend a diet rich in fruits and vegetables, regardless of whether they are conventionally grown or organic. Research indicates that transitioning from conventional produce to organic options, which do not use certain synthetic pesticides, can significantly reduce pesticide biomarkers in the body within a few days.
EWG advises prioritizing organic purchases for highly contaminated items listed in its Shopper’s Guide to Pesticides in Produce. This guide includes the “Dirty Dozen” list of produce with the highest detected pesticide residues and the “Clean Fifteen” list for items with the lowest residues.