Research shows microplastics from food and water can cross into the brain and worsen Alzheimer’s-like symptoms, especially in people with the APOE4 gene. The findings raise urgent concerns about how environmental toxins affect long-term brain health.
Tiny plastic particles from everyday products like disposable cups and food containers are turning up in the brain — and new research suggests they may worsen the risk of Alzheimer’s disease in people with genetic susceptibility.
When Plastic Reaches the Brain
Micro- and nanoplastics are now everywhere: in the water we drink, the food we eat, and even the air we breathe. Once inside the body, these particles travel through different systems and can even cross the blood–brain barrier, a protective shield meant to keep out harmful invaders like viruses.
A research team led by Jaime Ross, assistant professor at the University of Rhode Island’s College of Pharmacy, set out to study what happens when these plastics accumulate in the brain. Her findings, published in Environmental Research Communications, reveal that exposure may accelerate Alzheimer’s-like symptoms — particularly in individuals carrying the APOE4 gene, a genetic variant linked to a higher likelihood of developing the disease.
A Gene–Environment Interaction
To test the impact, Ross and her colleagues worked with genetically modified mice carrying either the APOE4 gene or the more common APOE3 variant. Over three weeks, the mice were given drinking water laced with micro- and nanoplastics, including polystyrene — the same material used in Styrofoam takeout boxes and plastic cups.
As expected, the plastics spread through the mice’s bodies, including their brains. What surprised researchers was how the effects mirrored Alzheimer’s-related symptoms in humans — and how they differed between males and females.
Male mice with APOE4 exposure showed behavioral signs of apathy, such as lingering in open, vulnerable areas instead of seeking cover.
Female mice with APOE4 exposure struggled with memory tasks, failing to recognize new objects in their environment.
This pattern echoes the way Alzheimer’s often presents in people: men tend to show greater apathy, while women more frequently experience memory decline.
Why It Matters
The study highlights how environmental toxins, combined with genetic risk, could play a major role in brain health. Carrying the APOE4 gene doesn’t guarantee Alzheimer’s, but Ross notes that factors like diet, exercise, and now exposure to microplastics may influence who develops the disease and how quickly it progresses.
Microplastics are not just widespread — they are persistent. A recent URI study found that the top two inches of sediment in Narragansett Bay alone hold more than 1,000 tons of plastic fragments. If these particles can alter brain function in mice within weeks, the potential long-term effects in humans demand urgent investigation.
The Call for Action
Ross is pushing for more research and regulation, pointing to proposed legislation like the Microplastics Safety Act, which would require the FDA to investigate how these particles affect human health — particularly in children and vulnerable populations.
“What we’re seeing in mice resembles what we observe in Alzheimer’s patients,” Ross explained. “It’s a warning sign that environmental toxins like microplastics could be shaping disease outcomes in ways we’ve only just begun to understand.”