Scientists have identified five distinct ways in which microplastics can damage the brain. Their findings also shed light on how these tiny particles may contribute to Alzheimer’s and Parkinson’s disease.
A study published in Molecular and Cellular Biochemistry suggests that microplastics—now found in countless everyday products—can trigger inflammation and cause serious brain damage.
We ingest 250 grams of microplastics every year
According to Professor Kamal Dua, a pharmaceutical sciences researcher and co-author of the study, adults consume roughly 250 grams of microplastics each year—about the equivalent of a dinner plate. These particles enter the body through ingestion and inhalation. “We are exposed to microplastics from many different sources,” he explains, “including contaminated seafood, salt, processed foods, tea bags, plastic cutting boards, plastic bottles, foods grown in polluted soil, as well as fibers released from carpets, household dust, and synthetic clothing.”
The most common plastics involved include polyethylene, polypropylene, polystyrene, and polyethylene terephthalate (PET). While a large portion of these microplastics is expelled from the body, research shows that some accumulate in organs over time, particularly in the brain.
Professor Dua collaborated with researchers from the University of Sydney in Australia and Auburn University in the United States to better understand how these substances interfere with normal brain cell function.
Oxidative stress and damaged neurons
The researchers identified five main mechanisms through which microplastics disrupt normal brain activity:
• activation of immune cells;
• increased oxidative stress;
• disruption of the blood–brain barrier;
• impairment of mitochondrial energy production;
• direct damage to neurons.
The study shows that microplastics weaken the blood–brain barrier, making it more permeable. This allows microplastics to enter the bloodstream, where they are recognized as foreign substances. The body responds by activating immune cells and inflammatory molecules, which further damage the barrier itself.
Microplastics also raise levels of reactive oxygen species—unstable molecules that can harm cells—while simultaneously weakening the body’s antioxidant defenses that normally keep these molecules in check.
In addition, the researchers found that microplastics interfere with mitochondrial energy production, slowing down cellular processes. In the brain, this lack of energy reduces neuronal activity and can eventually lead to lasting neurological damage.
“All of these mechanisms interact with one another, amplifying brain damage,” Professor Dua cautions.
Microplastics may increase the risk of Parkinson’s disease by causing damage to dopaminergic neurons. © Pixel-Shot, Adobe Stock
Acting quickly to reduce our exposure
The study also explored potential links between microplastics and neurodegenerative diseases. The researchers suggest that microplastics in the body may promote the buildup of beta-amyloid and tau proteins, both strongly associated with Alzheimer’s disease.
As for Parkinson’s disease, the study indicates that microplastics could increase the risk of developing the condition by damaging dopaminergic neurons. While further research is needed to confirm a direct causal link, the findings are concerning enough for researchers to call on health authorities to act.
“We need to change our habits and reduce our reliance on plastic,” concludes Dr. Keshav Raj Paudel, co-author of the study. “Avoid plastic containers and cutting boards, limit the use of tumble dryers, choose natural fibers over synthetic ones, and reduce consumption of processed and packaged foods to protect our health.”
