Rising microplastic levels in brain tissues raises health concerns
New evidence of increasing microplastic accumulation in human organs demonstrates urgent need to address plastic pollution and develop mitigation strategies.
The study, published in Nature Medicine, found microplastic and nanoplastic concentrations in brain tissues reached median levels of 4,917 micrograms per gram in 2024 samples, up from 3,345 micrograms per gram in 2016.
Methodology and detection
The research team, led by Dr Matthew Campen, analysed tissue samples from the liver, kidney, and brain, finding plastic particles in all three organs. However, brain tissue contained substantially higher concentrations - seven to 30 times greater than those found in liver or kidney samples.
The study also analysed historical brain tissue samples from 1997-2013, finding significantly lower concentrations compared to current levels.
How do microplastics impact human health?
The findings reveal a concerning trend of increasing plastic accumulation in human tissues. Polyethylene, the most common plastic globally produced, comprised around two thirds of detected particles in brain tissue.
The researchers found the plastic particles primarily existed as tiny fragments less than 200 nanometers in length - smaller than a human blood cell. Their microscopic size means they can potentially cross biological barriers that usually protect our organs from harmful substances.
Brain samples from patients with dementia showed substantially higher plastic concentrations, averaging more than five times higher than in non-dementia samples, although the researchers note that the study does not prove that microplastics caused the medical conditions.
However, researchers also found that plastic concentrations were not influenced by age, suggesting that people may be able to expel the material over time.
Professor Tamara Galloway, Professor of Ecotoxicology at the University of Exeter, describes the implications of these findings: “This is significant because it suggests that if we were to reduce environmental contamination with microplastics, the levels of human exposure would also decrease, offering a strong incentive to focus on innovations that reduce exposure.”
Future directions
The researchers conclude that these findings highlight “a critical need to better understand the routes of exposure, uptake and clearance pathways and potential health consequences of plastics in human tissues, particularly in the brain.”
It calls for expanded research efforts to understand whether microplastics play a role in neurological disorders or other health effects.
Studies from the Minderoo Foundation and the University of São Paulo last year also raised the alarm on the growing health crisis linked to exposure to microplastics.
However, careful interpretation of the study is needed given the small sample size and questions over its analytical methodology, according to Professor Oliver Jones, Professor of Chemistry at RMIT University.
Jones 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.”
