Human brains now contain more microplastics than ever and may cause dementia, new research suggests.
Scientists analysing the brains of people who died in 2024 compared them with those who died in 2016 — and found that the amount of plastic that had accumulated was 50 per cent higher.
They also found higher amounts of tiny plastic particles in the brains of people who died with dementia than people without a dementia diagnosis.
Researchers at the University of New Mexico and others said their findings may be a result of ‘rising global concentrations of environmental plastics’.
To get into the brain, plastics have to cross the blood-brain barrier — a layer of cells surrounding the brain which acts as a filter to prevent the entry of harmful substances.
The most commonly found plastic in the brain — polyethylene — is commonly used to make bags and singe-use water bottles which are frequently dropped as litter and made up 70 per cent of the tiny plastic pieces found.
Other plastics included polypropylene — which is also used for food and drink containers and synthetic rubber.
The Daily Mail, with the Turn the Tide on Plastics and Banish the Bags campaign, has long fought against the growing amount of plastic pollution in the environment.
Human brains now contain more microplastics than ever and may cause dementia, new research suggests
The most commonly found plastic in the brain — polyethylene — is commonly used to make water bottles
Matthew Campen, a toxicologist and professor of pharmaceutical sciences at the University of New Mexico analysed the distribution of microplastics and nanoplastics in brains taken from cadavers.
The authors found that liver and brain samples from 2024 had significantly higher concentrations of plastic micro- and nanoparticles than those from 2016.
They also found a higher concentration of micro- and nanoplastic particles in 12 brains from individuals with a documented dementia diagnosis than in those without.
The authors note that the findings identify an association but do not establish a causal link between plastic particles and health effects.
The samples were all taken from individuals in New Mexico and the US East Coast, and the authors state that further research will be needed to establish if plastic pollution in the brain and other organs is also prevalent elsewhere.
Writing in Nature Medicine, the authors said: ‘Total mass concentration of plastics in the brains analysed in this study increased by approximately 50 per cent in the past eight years.’
The findings come following warnings from scientists at Universitat Autònoma de Barcelona that a single tea bag can release billions of dangerous microplastics into the body.
During their experiments, the team found that most of these microplastics are taken up by the cells in the gut.
The findings come following warnings from scientists at Universitat Autònoma de Barcelona that a single tea bag can release billions of dangerous microplastics into the body
Microplastics, seen here as the black dots, were found in the semen samples of 36 participants in a recent trial in China
However, they found that some can even enter the cell nucleus — the part of the cell that houses genetic material.
Worryingly, the long-term effects of these microplastics on human health remain unclear.
‘The potential health implications of environmental micro/nanoplastics (MNPLs) are increasingly concerning,’ the researchers said.
‘Beyond environmental exposure, other sources such as food packaging, including herbal/teabags, may also be significant.’
Microplastics were also found in semen samples of 36 volunteers in a recent Chinese study.
Of the new findings, Professor Oliver Jones, Professor of Chemistry at RMIT University urged caution and said it was too early to say ‘our brains are now made of plastics’.
He said that 52 samples from just two years was not enough to discern a trend, and samples would also need to be taken from individual years between 2017 and 2023 to see if there was ‘an actual trend or just a random variation’.
He added that there is a risk that plastics in the samples may have come from potential contamination in the laboratory.
He added: ‘Overall, the work is interesting, but the low sample numbers and potential analytical issues mean that care should be taken when interpreting the results.
While it is not impossible that there are microplastics in the brains of some people, this study does not prove that this occurs, and, as the authors themselves note, there is as yet no strong evidence of any health effects.’
Dr Antonis Myridakis, Lecturer in Environmental Sciences, Brunel University of London, said: ‘The finding that microplastics are accumulating in human brains is concerning, however, it is too early to draw conclusions about direct health risks.’
