Microplastics reach the human brain
Researchers detect plastic particles in the liver, kidneys, and brain. The pathways of absorption and potential health effects remain unclear.
Plastic particles detected in organs
It is no longer a secret that global plastic waste is increasing exponentially, with a large portion ending up in the environment, breaking down into microplastics, and remaining detectable for centuries. It’s also no secret that animals choke on plastic particles, plastic bags are found in the deep sea, and microplastics have spread as far as the Arctic.
Only one area seemed to be protected from the flood of plastic: the human body. But a study published in February 2025 shows that microplastics also reach human organs – deposits were found in the examined liver, kidney, and brain tissues. And the effects on human health remain unclear.
PP, PE, and PVC deposits in the human body
In the study, the major organs – liver, kidney, and brain – of individuals who died in 2016 were compared with those of individuals who died in 2024. Using various methods to detect micro- and nanoplastics in tissue, the researchers found accumulations of plastic particles in all three organs.
A clear difference in concentration was found between the two groups – the organs of individuals who died in 2024 showed significantly higher levels of micro- and nanoplastics. The detected plastic particles were primarily composed of PE (polyethylene), which is commonly used in shopping bags, plastic sacks, and food packaging. In addition to PE particles, other polymers were identified, mainly PP (polypropylene) and PVC (polyvinyl chloride).
A closer look at the group of individuals who died in 2024 revealed that the concentration of plastic particles in brain samples was significantly higher than in the liver or kidneys of the same individuals. Furthermore, the brain samples of people with dementia consistently showed higher levels of micro- and nanoplastics compared to those without dementia.
It is quite notable that the concentration of plastics in the organs does not depend on age, sex, origin, or cause of death. The only difference can be observed between the two groups based on the time of death – the group of individuals who died in 2024 shows a noticeably higher concentration of polyethylene and other polymers in all organs.
Impact on health
The exact effects on human health are still unclear. Currently, there are only a few studies on mammals that examine the impacts of micro- and nanoplastics.
In 2023, researchers studied the effects of PET nanoplastics on zebrafish embryos and found that the tiny plastic particles accumulated in several organs of the embryos, including the liver, intestine, kidney, and brain. These accumulations led, among other things, to behavioral disorders in the embryos and impaired liver function.1
Other studies have detected microplastics in the placenta of pregnant women and in the testes of men. Since sperm counts – and consequently male fertility – have been declining for some time, this development could be exacerbated by the accumulation of plastic particles in the testes.2
The study published in February 2025 also points to a higher accumulation of micro- and nanoplastics in the brains of patients diagnosed with dementia. However, this does not necessarily mean that plastic particles in the brain are a cause of dementia. Since dementia patients often exhibit a weakened blood-brain barrier and a reduced ability to eliminate toxic substances from the brain, the high microplastic load in human brains is more likely to be a consequence of the disease.
Distribution and uptake processes unclear
Micro- and nanoplastic particles are present, among other places, in the air, drinking water, and food – which inevitably leads to their ingestion by animals and humans.
The recently published study is surprising in that it found no correlation between the age of the deceased and higher plastic concentrations in the body. Instead of age, the time of death is relevant – suggesting that plastic particles do not accumulate steadily over a lifetime, but rather that the exponentially increasing concentration of micro- and nanoplastics in the environment is leading to a rise in their levels within the human body. This is especially clear in the examined brains: the amount of plastic particles increased by about 50% over the past eight years.
In zebrafish embryos exposed to a consistent amount of nanoplastics over an extended period, uptake was observed up to a certain point – after which the amount in the body remained constant. The plastic uptake increased with higher concentrations in the environment, and once the fish were no longer exposed to the plastics, the particles were eliminated.3
How micro- and nanoplastics enter the human body and distribute within it is still largely unexplored. It is especially unclear how these particles reach the brain, are absorbed there, and whether they can be eliminated again. Researchers consider it quite possible that a balance could be established between intake, excretion, and environmental exposure.
This highlights the importance of gaining a better understanding of the processes of intake, distribution, and elimination of plastics in the human body – especially in the brain – and of investigating the potential health consequences.
Sources
Studie: https://www.nature.com/articles/s41591-024-03453-1
1: https://www.uni-leipzig.de/newsdetail/artikel/wie-nanoplastik-den-stoffwechsel-beeinflussen-kann-2023-03-08
2: https://www.rnd.de/wissen/mikroplastik-in-hoden-nachgewiesen-schadet-es-der-fruchtbarkeit-CENWHCD6KJBNFK5AIT5C4UACTQ.html
3: https://www.uni-leipzig.de/newsdetail/artikel/wie-nanoplastik-den-stoffwechsel-beeinflussen-kann-2023-03-08
