Tiny plastic particles have been found deep in the human body, including the brain—but their health impact remains unclear
PARIS:
Microscopic plastic particles—known as microplastics—have been discovered lodged inside the human brain, raising concerns among scientists and health experts. While the full extent of their effects remains unknown, recent studies and growing evidence suggest this issue may pose a future public health challenge.

These virtually invisible plastic fragments are now found everywhere—from mountaintops to ocean floors, and in the air we breathe and food we eat. They’ve already been detected in human lungs, hearts, placentas, and most recently, in brain tissue—crossing the once-thought-impenetrable blood-brain barrier.

This worrying trend has become a focal point in international talks on the world’s first plastic pollution treaty, with the latest negotiations set to take place in Geneva next week.

The Study That Sparked Global Attention

The most notable research to date appeared in Nature Medicine in February. Scientists examined brain tissue from 28 individuals who died in 2016 and 24 who died in 2024 in New Mexico, USA. Results showed an increase in microplastic levels over time.

Lead researcher and toxicologist Matthew Campen reported that in some cases, the brain samples contained the equivalent of a plastic spoon’s worth of microplastics—possibly up to 10 grams, which he likened to the size of a crayon.

The findings sparked alarm and headlines worldwide. But not all experts are convinced.

Skepticism from the Scientific Community

Several researchers have urged caution. Toxicologist Theodore Henry from Heriot-Watt University in Scotland told AFP that while the study is “interesting,” it requires independent verification.

“Speculation about the potential effects of plastic particles on health currently goes far beyond the available evidence,” he said.

Oliver Jones, a chemistry professor at RMIT University in Australia, also questioned the findings, noting the small sample size and limited geographical scope. He added that it seemed “rather unlikely” that brains could hold more plastic than raw sewage, as the study implied.

Importantly, none of the individuals in the study were ill prior to death, and no direct link between plastic presence and health harm was established.

Further complicating credibility, some duplicated images were found in the study, though experts say these do not undermine the main findings.

Still No Conclusive Proof of Harm

To date, most research in this area remains observational, meaning it can suggest correlations but cannot prove cause and effect.

One such observational study, published in the New England Journal of Medicine last year, found that microplastics in blood vessels were linked to higher risks of heart attacks, strokes, and mortality in people with artery disease.

Animal studies offer similar clues. A January 2025 study in Science Advances found microplastics in mouse brains, with researchers reporting rare blood clots caused by plastic particles obstructing brain cells. However, scientists emphasize that mice and humans are biologically different, so the findings can’t be directly applied.

The World Health Organization (WHO), in a 2022 review, concluded there is still “insufficient evidence” to determine whether microplastics pose risks to human health.

Why Scientists Are Calling for Precaution

Despite the uncertainty, many experts advocate for urgent action based on the precautionary principle. This approach argues that waiting for absolute scientific certainty could delay necessary protections.

A new report by the Barcelona Institut e for Global Health, released ahead of the Geneva treaty talks, echoes this concern.

“Policy decisions cannot wait for complete data,” the report stated.
“By acting now to reduce exposure, improve risk assessments, and protect vulnerable groups, we can prevent this from escalating into a larger public health crisis.”

As the world grapples with plastic pollution on a planetary scale, the mystery of what microplastics may be doing inside our bodies—particularly our brains—remains unsolved, but increasingly impossible to ignore.