Brain particularly affected Researchers are finding more and more plastic particles in the body

More and more microplastics are being found in human tissue - particularly in one specific organ. A new study shows the increase, but the health consequences are still unclear.

Tiny plastic particles are increasingly accumulating in the tissues of the human body. A US research team has found significantly more nano- and microplastics in the livers and brains of people who died in 2024 than in samples from 2016. The contamination was particularly high in the brain - up to 30 times higher than in the liver or kidneys, reports the group led by Matthew Campen from the University of New Mexico in the journal Nature Medicine.

On the trail of the tiniest particles

Microplastics have already been detected in the lungs, intestines and placenta. However, conventional microscopy methods usually only detect particles larger than five micrometers. "Smaller nanoplastics are therefore unintentionally excluded," the scientists write. A micrometre is a thousandth of a millimetre, a nanometre a millionth of a millimetre. Campen's team now used special infrared and electron microscopy to determine the quantities of plastic more precisely.

The researchers analyzed tissue samples from the livers, kidneys and brains of 24 deceased people from 2024 and compared them with samples from 28 deceased people from 2016. The result: the average concentration of microplastics and nanoplastics in the kidneys was similar in 2016 and 2024. However, significantly higher values were found in the liver and brain samples in 2024 - in the liver, the average concentration rose from 141.9 to 465.3 micrograms per gram of tissue, and in the brain from 3,420 to 4,763 micrograms per gram.

Particularly high exposure in people with dementia

The team also used a chemical analysis to determine the composition of the plastic. They found that polyethylene, which is used for films and bottles, was the most common type of plastic. It made up 40 to 65 percent of the plastic in the liver and kidneys, and as much as 75 percent in the brain. Analyses of preserved brain tissue from 1997 to 2013 also showed that the amount of tiny plastic has increased significantly in recent years.

The contamination was particularly high in twelve other brain samples from 2019 to 2024 from people with confirmed dementia: they contained between 12,000 and 48,000 micrograms of plastic per gram of tissue. However, the research group emphasizes that their study does not prove a direct cause-and-effect relationship: "These data are associative and do not prove the causal role of such particles in health impairment."

Some differences in the brain samples could also be due to geographical differences, as the samples were taken in New Mexico on the one hand and on the east coast of the USA on the other. Overall, further longer-term studies with larger, more diverse populations are needed to determine trends in the accumulation of micro- and nanoparticles and their potential health effects - particularly on the human brain.

Previous study showed neurological problems in mice

Just recently, a group led by Haipeng Huang from the Chinese Research Academy of Environmental Sciences in Beijing presented research findings showing that microplastics can potentially clog blood vessels in the brains of mice. According to the study, the affected mice moved less, were less able to orient themselves and had less stamina. However, the authors of the study wrote in the journal "Science Advances" that the results cannot be easily transferred from mice to humans due to differences in brain structure.