Scientists challenge health warnings regarding microplastics, attributing issues to obesity and dismissing certain studies as ‘a joke’

You might want to hold onto that scratched, stained, and heavily used 12-year-old cutting board for now! That vintage fermentation lab covered in knife marks may not be as dangerous as previously thought.

For years, scientists have cautioned that microplastics are present in everything from the food we consume to the cleaning supplies we utilize. We have been informed that these microplastics are accumulating within our bodies and presenting a new threat to our health.

However, some scientists are now challenging this notion, with one researcher even dismissing the studies that sound the alarm as “a joke.”

Recent high-profile reports asserting that micro- and nanoplastics (MNPs) have penetrated the human brain, arteries, and testes are encountering significant scientific pushback. Experts caution that many of these widely publicized findings may stem from methodological errors, contamination, and false positives instead of actual plastic ingestion.

“The brain microplastic paper is a joke,” stated Dusan Materic, head of research at the Helmholtz Center for Environmental Research (UFZ). Materic is among several scientists declaring that prior studies concerning the harm microplastics cause to the human body are exaggerated.

Chemist Roger Kuhlman remarked that the evidence presented in earlier studies was riddled with more holes than a cutting board, amounting to a “bombshell,” he informed the publication.

“This is truly compelling us to reevaluate everything we believe we know about microplastics in the body,” Kuhlman, a former chemist at the Chemical Company, told the publication. “Which, it turns out, is very little. Many researchers are making extraordinary claims without providing even ordinary evidence.”

The controversy revolves around a surge of research that has grabbed global headlines, including a study suggesting the average human brain might contain a significant amount of MNPs. By November, however, a team of scientists formally challenged this study in a “Matters arising” letter, citing insufficient contamination controls and a lack of validation steps.

The technical core of the dispute lies in Py-GC-MS, a process where samples are vaporized to identify molecules by weight. Environmental chemist Cassandra Rauert observed that this technique is currently unsuitable for detecting polyethylene or PVC in human tissue because molecules from human fat can mimic the signal of these plastics. Her research identified 18 studies that failed to account for these false positives. Furthermore, Rauert argued it is “biologically implausible” that the reported mass of plastic could reach internal organs, as particles between three and 30 micrometers are unlikely to cross biological barriers.

Alternatively, the scientists proposed that rising obesity levels might offer a better explanation for health issues than an increase in plastic accumulation.

Adding to the skepticism, Fazel Monikh, a nanomaterials expert at the University of Padua, noted that particulate materials undergo biotransformation once they enter a living organism. He explained that even in the “highly unlikely scenario” that an intact particle reached a protected organ like the brain, it would not “retain the appearance shown in most of the reported data.” Consequently, many experts find the results and interpretations of these studies to be scientifically unconvincing.

Experts such as Frederic Béen describe the study of microplastics in humans as a “super-immature field” where the rush to publish has resulted in shortcuts and the neglect of routine scientific checks.

These methodological flaws have real-world repercussions, including “scaremongering” and the emergence of costly, unscientific treatments claiming to “clean” blood of plastics for fees reaching £10,000 (approximately $13,500). While the presence of plastics in the body remains a “safe assumption” for most researchers, they stress the necessity for robust, standardized techniques to accurately guide public health policy. In the interim, experts recommend precautionary steps, such as using charcoal water filters and avoiding heating food in plastic containers.

For this story, journalists utilized generative AI as a research tool. An editor verified the accuracy of the information prior to publishing.