Increasing levels of microplastics and nanoplastics (MNPs) in the environment raise concerns about their impact on human health. Various methods, like advanced spectroscopy and microscopy techniques, have detected MNPs in human organs such as the kidney, liver, and brain.
According to a new study from the University of New Mexico Health Sciences, the brain contains higher concentrations of plastic than the liver or kidneys. The microplastics in the brain are present at much higher concentrations than in other organs.
Toxicologist Matthew Campen, PhD, Distinguished and Regents’ Professor in the UNM College of Pharmacy, said, “The accumulation rate mirrors the increasing amounts of plastics waste on this planet. This really changes the landscape. It makes it so much more personal.”
Additionally, they observed that much of the plastic appears to be much smaller than previously appreciated—on the nanometer scale, about two to three times the size of viruses.”
Researchers found that brain tissue from people with dementia had up to ten times more plastic than others. However, they can’t confirm if higher plastic levels caused the dementia or if the disease caused the accumulation.
The team used a method to identify and measure microplastics in tissues. They’ve previously used it for human placentas and testes from humans and dogs.
The current study examined brain tissue samples from autopsies stored by the New Mexico Office of the Medical Investigator. These samples were retained for seven years and included tissues from 2016 and 2024, all taken from the frontal cortex region of the brain.
Researchers dissolved brain tissue and used a centrifuge to isolate small plastic pellets. These pellets were heated to 600 degrees Celsius (pyrolysis), and the gases released were analyzed to identify 12 types of polymers, with polyethylene being the most common.
Using electron microscopy, the team found tiny, sharp plastic shards in the tissue, small enough to cross the blood-brain barrier. It’s not clear how these particles get into the brain or what effects they may have, although they might obstruct blood flow or interfere with brain connections.
The researchers suspect that most microplastics in the body come from food, especially meat. They believe plastics build up in the food chain due to agricultural practices and found high concentrations of plastic in store-bought meat.
Microplastics build up in the brain’s myelin sheath, which wraps around neurons and helps with signal transmission. This might explain higher plastic concentrations in the brain.
Even if plastic production stopped today, existing plastics would continue breaking down into micro- and nano-plastics for decades, increasing their environmental concentrations.
Campen notes that even small amounts of contaminants can be harmful and stresses the global health threat microplastics pose. Despite consumers often dismissing such warnings, the alarming new findings might finally get their attention, as no one wants plastic in their brain.
Journal Reference:
- Nihart, A.J., Garcia, M.A., El Hayek, E. et al. Bioaccumulation of microplastics in decedent human brains. Nat Med (2025). DOI: 10.1038/s41591-024-03453-1
Source: Tech Explorist
