Tiny plastic particles have been found in human brain tissue, raising concerns over their impact on health. Scientists have detected a significant increase in microplastics and nanoplastics (MNPs) in the brain over the past decades. The particles, commonly present in air, water, and food, have now been identified within human tissue, challenging previous assumptions about the brain’s protective barriers. Researchers are working to understand the long-term consequences of this plastic infiltration.

Rising Plastic Levels in Brain Tissue

According to the study published in Nature Medicine, 91 brain samples collected from individuals who died between 1997 and 2024 were analysed. Reports indicate a 50 percent increase in MNP concentrations from 2016 to 2024, with median levels rising from 3,345 micrograms per gram to 4,917 micrograms per gram. Andrew West, a neuroscientist at Duke University, told Science News that the sheer quantity of plastic detected was unexpected, stating that he didn’t believe it until he saw all the data.

Unexpected Particle Shapes and Sources

Findings suggest that the plastic particles are not uniform. Many were thin, sharp fragments rather than the engineered beads often studied in labs. Richard Thompson, a microplastic pollution expert at the University of Plymouth, told Science News that these plastics originate from everyday products such as grocery bags and bottles. Polystyrene, frequently used in medical and food industries, was found in lower amounts compared to polyethylene.

Potential Links to Neurological Conditions

Higher MNP levels were found in the brains of 12 individuals diagnosed with dementia, but researchers have not confirmed a direct causal link. Some scientists speculate that neurological changes associated with dementia may increase plastic accumulation. Phoebe Stapleton, a toxicologist at Rutgers University, told Nature Medicine that further research is required to understand the biological impact, stating, that the next steps will be to understand what they are doing in the brain and how the body responds to them.