Study links fruit, vegetable consumption to spikes in pesticide metabolites in pregnant women

A new study published in the International Journal of Hygiene and Environmental Health has found that concentrations of organophosphate (OP) pesticide metabolites in the urine of pregnant women peak between six and 12 hours after the consumption of fruits and vegetables treated with these chemicals.

According to the researchers, analysis of 431 urine samples collected from 25 pregnant women revealed high detection rates of several OP metabolites, including dimethylthiophosphate (DMTP) at 96 per cent, dimethylphosphate (DMP) at 94 per cent, diethylphosphate (DEP) at 89 per cent, and diethylthiophosphate (DETP) at 77 per cent. The samples were collected over two separate 24-hour periods early in pregnancy.

The study links the presence and concentration of these metabolites directly to dietary exposure, particularly the consumption of foods treated with organophosphate pesticides.

Researchers say the findings underscore the potential benefits of adopting organic diets, especially for pregnant women and young children who are considered more vulnerable to chemical exposure.

The research draws on data from the Plastics and Personal-care Product use in Pregnancy (P4) Study, conducted in Ottawa, Canada, between 2009 and 2010.

A total of 80 pregnant women were initially recruited, while a subset of 25 participants provided multiple urine samples—up to 10 each—across one weekday and one weekend day during early pregnancy.

Participants also maintained detailed food diaries beginning 24 hours before the first urine sample and continuing throughout the 24-hour collection period.

Researchers noted that this is the first study to closely examine the short-term variability of organophosphate metabolites in maternal urine over a 24-hour cycle.

The findings provide new insight into the primary sources of exposure and how rapidly OP levels fluctuate following food consumption in pregnant populations.

The metabolites measured in the study are breakdown products of widely used organophosphate pesticides, including malathion, chlorpyrifos, diazinon, dimethoate, parathion and fenitrothion—chemicals with current or historical use in both Canada and the United States.

Organophosphates are commonly applied in agriculture, making food ingestion the most frequent exposure route for the general population.

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The authors explained that OPs typically break down into dialkyl phosphates (DAPs), which are excreted in urine.

They noted that in 2010 alone, Canada sold more than 586,000 kilograms of active pesticide ingredients in chemical groups that include dithiophosphates, phosphates and thiophosphates.

Unlike earlier studies that relied on single urine samples, the current research examined multiple samples over time, allowing scientists to observe daily variations in exposure. During the study periods, participants logged 3,753 food and beverage items across 14 major food categories, including fruits, vegetables, grains, dairy and meats.

Results showed that OP metabolite concentrations rose following the consumption of fruits and vegetables, particularly on weekend days. The researchers concluded that these findings align with existing scientific literature linking dietary intake of produce to elevated pesticide metabolite levels.

Cited research from cohorts in the United States, China, Canada and Europe has consistently found associations between higher maternal OP metabolite levels and adverse neurodevelopmental outcomes in children, as well as higher metabolite concentrations among individuals with greater fruit and vegetable consumption.

The authors and public health advocates argue that reducing exposure is critical, particularly during pregnancy.

They point to organic agriculture as a viable solution, noting that organic farming avoids synthetic pesticides and fertilizers while producing food that may pose fewer health risks to consumers and farmworkers.

The findings contribute to ongoing global discussions about pesticide regulation, food safety and the need for agricultural practices that protect human health and the environment, especially for future generations.