Are micro- and nanoplastics accumulating in the brain promoting neurological dysfunction and disease?

Are micro- and nanoplastics accumulating in the brain promoting neurological dysfunction and disease? Pamela J. Lein considers whether micro- and nanoplastics are accumulating in the brain and the question of whether they are promoting neurological dysfunction and disease. In February 2025, Nature Medicine published a startling report by a team of researchers at the University of New Mexico that estimated the human brain was 0.5% plastic by weight. This finding was based on their analysis of micro- and nanoplastics (MNPs) in autopsied human brains. Comparative analyses of the MNP levels in human brain, liver, and kidney samples collected in 2016 or 2024 revealed that not only were these tiny plastic particles accessing the brain, but they were actually accumulating in the brain. Specifically, brain samples contained up to 30 times more MNPs than samples from the same person’s liver or kidney.