Research findings are accumulating that microplastics are harmful not only to the environment but also to human health. Recently, an international research team announced that microplastics may accumulate more in the brain than in the kidneys or liver. Microplastics accumulating in the brain could potentially impact neurological disorders.
An international research team, including the University of New Mexico, published results of an investigation into the distribution of microplastics in human brain, liver, and kidney tissues in the international journal "Nature Medicine" on the 4th.
Microplastics refer to ultrafine plastic particles ranging in size from 1 NANO (1 billionth of a meter) to 500 micrometers (1 millionth of a meter). The concentration of microplastics in the environment has increased exponentially worldwide over the past 50 years. In South Korea, the analysis of microplastic contamination in sediment along the southern coast showed a continuous increase since the 1970s, and since the 2000s, the rate of increase has been approximately double the global rate of plastic production growth, which is 8%.
The researchers analyzed microplastics in human brain (frontal lobe), liver, and kidney tissues obtained through autopsies conducted in 2016 and last year. The major microplastic components detected were polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), and styrene-butadiene rubber (SBR). Particularly, the proportion of polyethylene in brain tissue was the highest at over 75%.
The concentration of microplastics found in the liver and kidneys in 2016 was similar; however, it accumulated at a much higher concentration in brain tissue. Samples collected last year also showed that the concentration of microplastics in the brain was significantly higher than in the liver and kidneys.
The concentration of microplastics in samples from the liver, kidneys, and brain was much higher last year than in 2016. This indicates that microplastics have accumulated more in the human body over the past eight years. In particular, the concentration of microplastics in the brain increased by 50% compared to 2016. The researchers explained, "As the concentration of microplastics in the environment increases, the amount accumulated in the body is likely increasing as well."
The researchers also investigated the distribution of microplastics in the brains of 12 patients diagnosed with dementia. As a result, the concentration of microplastics in the brains of dementia patients was found to be more than seven times higher. The researchers noted, "Microplastics were primarily concentrated in the blood-brain barrier and immune cells, and they could potentially be linked to neuroinflammation or damage to the blood-brain barrier (BBB)."
This is consistent with previous research. On the 22nd of last month, a joint research team from the Chinese Academy of Environmental Sciences, National University of Singapore, and Duke University in the U.S. reported that microplastics can pass through the blood-brain barrier and be phagocytosed by brain immune cells, which can lead to blockages in blood vessels and potentially result in thrombosis.
However, this study does not prove a direct causal relationship between microplastics and the development of dementia or other neurological disorders. The researchers emphasized that further studies are needed on the pathways of microplastic entry into the body, the mechanisms of accumulation in the brain, and the processes of removal and excretion, and that long-term studies involving various populations should also be conducted.
Reference materials
Nature Medicine (2025), DOI: https://doi.org/10.1038/s41591-024-03453-1
Science Advances (2025), DOI: https://doi.org/10.1126/sciadv.adr8243