Researchers have found a buildup of microplastic particles in the human brain.

Nano- and microplastic particles are released into the environment, with sizes ranging from one nanometer (one billionth of a meter) to 500 micrometers (one millionth of a meter) in diameter. As noted by the authors of a new scientific study, most previous research utilized visual microscopic spectroscopy methods to identify particles in human tissues. However, the sizes of foreign "findings" often exceeded five micrometers, while solid particles were examined in organs such as the lungs, intestines, and placenta. Smaller particles remained invisible.

Researchers from the United States adopted a new approach. They relied, in part, on pyrolysis gas chromatography-mass spectrometry — an analytical method that combines the capabilities of a chromatograph and a mass spectrometer, used for the quantitative and qualitative determination of individual components in complex mixtures. Additionally, the scientists employed Fourier-transform infrared spectroscopy — an analytical technique widely used in industrial and scientific laboratories to study the structure of individual molecules and the composition of molecular mixtures. Furthermore, the researchers analyzed the material using electron microscopy with energy-dispersive spectroscopy.

The samples containing micro- and nanoparticles came from the liver, kidney, and brain tissues of deceased individuals after autopsy procedures conducted in 2016 and 2024. After examination, the medical professionals found significantly higher concentrations of microplastics in brain samples taken from the frontal cortex compared to liver and kidney tissue samples. Moreover, the plastic content in 2024 significantly exceeded similar levels found in internal organs eight years prior. The highest amounts detected were polyethylene, while the scientists also identified polypropylene, polyvinyl chloride, and butadiene-styrene rubber.

Subsequently, the researchers compared these results with brain tissue samples from earlier periods (1997-2013) and noted higher concentrations of plastic particles in the more recent samples. Notably, a greater number of fragmentary pieces were found in 12 brain samples from individuals with documented diagnoses of "dementia" than in those without such conditions. In the patients, significant deposits of fragments were observed in the walls of cerebral blood vessels and immune cells.

The authors pointed out that some differences in the brain samples could be attributed to geographical variations, as the samples were obtained from New Mexico and various locations along the East Coast of the United States. However, the results highlight the urgent need to better understand the pathways through which microplastics enter human tissues, their impact on health, and the potential consequences.

It is worth noting that, to date, there is no unequivocal evidence of harm from micro- and nanoplastics to humans. Obtaining such evidence is challenging, as there are virtually no human bodies that do not contain these plastic particles, making it impossible to compare the health of their owners with others. Ethically, it is not permissible to deliberately contaminate human bodies with microplastics in experiments, so uncertainty regarding the health risks posed by microplastics is likely to persist for a long time.

The scientific study has been published in the journal Nature Medicine.