The National Institutes of Health has awarded Arizona State University a $465,000 grant to compare the amount of micro and nanoplastics in the brains of people who died with Alzheimer's disease against those who died cognitively healthy. The project expands a small pilot that detected plastic-related signals in postmortem human brain tissue.
The work is led by Diego Mastroeni, associate research professor at the Biodesign Institute's ASU-Banner Neurodegenerative Disease Research Center.
His team will examine 100 autopsy brains, 50 from people with moderate-to-severe Alzheimer's and 50 from cognitively unimpaired controls. Samples come from the Arizona Study of Aging and Neurodegenerative Disorders and the Brain and Body Donation Program.
Researchers will focus on two brain regions. One is the olfactory bulb, a suspected entry point for particles inhaled through the nose. The other is the middle temporal gyrus, an area involved in memory that is affected early in Alzheimer's disease.
Also read: Nearly half of dementia cases could be prevented, and most risk factors are in your control
What the pilot found
A preliminary study, funded by a $60,000 grant from the Arizona Alzheimer's Consortium in October 2025, generated the working hypothesis. The team reported that plastic-related signals could be detected in postmortem human brain samples and that the amounts may differ between people with Alzheimer's and matched controls.
The new NIH funding enlarges the sample size so the group can account for age, sex, genetics and tissue quality, and start to test whether the pattern is reproducible.
"Right now, simply finding plastics in human tissue is not enough. Understanding whether those exposures have meaningful consequences will be essential to defining the environmental determinants of health in the 21st century," Mastroeni said.
Why the Alzheimer's question is being asked
The interest in a possible Alzheimer's link hardened after a study published in Nature Medicine in early 2025.
Also read: One bedtime drink added 84 minutes of sleep a night in early research
A University of New Mexico team led by toxicologist Matthew Campen reported that brain tissue collected in 2024 contained roughly 50 percent more micro and nanoplastics than tissue collected in 2016, and that concentrations in the brain exceeded those measured in the liver or kidney.
The same paper reported greater accumulation of plastic particles in a smaller group of brains from people who had a documented dementia diagnosis, with notable deposition in cerebrovascular walls and immune cells. The authors flagged the finding as a signal that needs follow-up, not proof of harm.
That is the question the ASU project sets out to test more rigorously. Higher plastic levels in the brains of people with dementia may reflect environmental exposure that contributed to disease, or they may reflect a disease process that traps particles more readily. The new study is designed to describe the pattern, not to prove cause.
What still is not known
No study to date has shown that micro or nanoplastics cause Alzheimer's disease. The ASU team will also examine whether people who lived in more disadvantaged neighborhoods carry higher plastic burdens in brain tissue, a question tied to environmental exposure rather than treatment.
Also read: Adding just half a tablespoon of olive oil a day may protect your heart and brain
Anyone worried about memory changes in themselves or a family member should raise the concern with a doctor rather than draw conclusions from early exposure research.
Also read: Your brain may be warning you about heart disease 3 to 8 years before it strikes