Americans Exposed to Fertility-Lowering Chemicals in Cheerios, Quaker Oats

In a pilot study^1,2,3 conducted by the Environmental Working Group and published in the February 15, 2024, issue of the Journal of Exposure Science & Environmental Epidemiology, findings revealed that 80% of Americans tested positive for chlormequat chloride, an agricultural chemical used as a pesticide and plant growth regulator.⁴

Moreover, the chemical was detected in 92% of oat-based foods examined, including popular brands such as Quaker Oats and Cheerios. As reported by the EWG:⁵

“The groundbreaking analysis of chlormequat in the bodies of people in the U.S. rings alarm bells, because the chemical is linked to reproductive and developmental problems in animal studies, suggesting the potential for similar harm to humans.”

EPA Considers Expanding Chlormequat Use in Crops

In the U.S., chlormequat chloride is currently only registered for use as a plant growth regulator (PGR) in ornamentals, but the Environmental Protection Agency recently proposed to expand the registration to barley, oat, triticale (a hybrid cereal grain derived from the crossbreeding of wheat and rye) and wheat as well, to give farmers another tool to increase yields.⁶ As explained by the EPA, chlormequat:⁷

“… works to control plant size by blocking the hormones that stimulate growth prior to bloom. In small grains like wheat, barley, oats, and triticale, lodging (the bending over or breakage of small grain stems) is a major production issue.

Lodging can severely limit grain yield and harvestability and have detrimental effects on grain quality. As a PGR, chlormequat chloride application decreases the height of the grain plant stem, resulting in reduced lodging and potentially increased grain yield.”

Doing so could come at a cost to consumers’ health, however. While the EPA claims “There are no dietary, residential, or aggregate … risks of concern,”⁸ the EWG⁹ cites evidence showing otherwise.

Chlormequat’s Toxic Effects Evident in Animal Studies

According to the EWG, historical and recently published animal studies have demonstrated:¹⁰

Chlormequat has also been shown to affect the endocrine systems of animals, although the exact mechanism is still unclear. Previous studies suggest chlormequat does not act like most other endocrine disrupting chemicals. For example, it does not use estrogen or androgen receptors and does not alter aromatase activity.

Instead, researchers have suggested it may affect the endocrine system by altering steroid biosynthesis and causing endoplasmic reticulum stress.¹¹ As noted by EWG,¹² “Although these studies focus only on the chemical’s potential effects on animals, they raise questions about whether it could also harm humans.”

Chlormequat Exposure Is on the Rise

As current testing indicates, individuals are already encountering chlormequat through food, primarily in imported grains. The EPA’s decision to authorize the importation of grains treated with chlormequat in 2018¹³ has contributed to this exposure.

Expanding its application as a plant growth regulator in the U.S. to encompass staple grains would evidently heighten exposure levels, potentially leading to significant adverse effects. As reported in the featured study:¹⁴

“Chlormequat chloride is a plant growth regulator whose use on grain crops is on the rise in North America. Toxicological studies suggest that exposure to chlormequat can reduce fertility and harm the developing fetus at doses lower than those used by regulatory agencies to set allowable daily intake levels.

Here we report the presence of chlormequat in urine samples collected from people in the U.S., with detection frequencies of 69%, 74%, and 90% for samples collected in 2017, 2018–2022, and 2023, respectively.

Chlormequat was detected at low concentrations in samples from 2017 through 2022, with a significant increase in concentrations for samples from 2023. We also observed high detection frequencies of chlormequat in oat-based foods.

These findings and chlormequat toxicity data raise concerns about current exposure levels, and warrant more expansive toxicity testing, food monitoring, and epidemiological studies to assess health effects of chlormequat exposures in humans.”

Continual Exposure Indicated by Data

The researchers also highlight that in urine samples collected from individuals in the U.K. and Sweden, chlormequat was identified in nearly 100% of participants, with frequencies and concentrations notably surpassing those of metabolites from other pesticides such as chlorpyrifos, pyrethroids, thiabendazole, and mancozeb. This suggests that individuals are probably ingesting higher quantities of chlormequat compared to the aforementioned pesticides.

The chemical has also been identified in serum and milk in animal studies. And, while human sampling to ascertain the presence of chlormequat in human serum and breast milk has not been conducted, the authors emphasize that “chemicals associated with reproductive harm in serum and milk have important implications for exposures during pregnancy and to infants.”

Chlormequat has a half-life in the body of about two to three hours, with a significant portion of administered doses being expelled within a span of 24 hours. So, the detection of the chemical in 80% of urine samples indicates ongoing exposure throughout the day for the majority of individuals.

In terms of quantity, the concentrations ranged from 0.27 micrograms to 52.8 mcg of chlormequat per gram of creatinine in the 2023 samples, with a median of 1.4 mcg.