Microplastics may be causing far greater harm to human health than previously recognised, with a new international review warning that these particles could accelerate neurodegenerative disorders such as Alzheimer’s and Parkinson’s.
The findings have triggered concern among scientists, who say the rapid infiltration of microplastics into food, air, and water may be laying the groundwork for a long-term neurological health crisis. Microplastics are tiny plastic particles, typically less than 5 millimeters in size, that come from the breakdown of larger plastic items or from primary sources like microbeads and resin pellets.
The review — led by researchers from the University of Technology Sydney (UTS) and Auburn University in the United States, and published in Molecular and Cellular Biochemistry — outlines five biological pathways through which microplastics can inflame and injure the brain. These include chronic immune activation, oxidative stress, disruption of the blood–brain barrier, mitochondrial damage, and direct neuronal injury.
Presently, more than 57 million people are living with dementia, and cases of Alzheimer’s and Parkinson’s are expected to surge in the coming decades.
Associate Professor Kamal Dua, a pharmaceutical scientist at the University of Technology Sydney (UTS), said adults may be consuming up to 250 grams of microplastics every year — roughly enough to fill a dinner plate.
“We ingest microplastics from a wide range of sources—contaminated seafood, salt, processed foods, tea bags, plastic chopping boards, bottled drinks, as well as plastic fibres from clothing, household dust, and carpets,” he said.
Although the body expels some of these particles, emerging research shows that microplastics can accumulate in major organs — including the brain. This raises concerns that long-term exposure may trigger or worsen neurological decline.
The review explains that microplastics may weaken the blood–brain barrier, allowing inflammatory molecules to seep into neural tissue. Once this barrier becomes “leaky”, immune cells remain in constant activation, driving a cycle of inflammation and oxidative stress that progressively damages brain cells.
Oxidative stress itself arises from an imbalance: the excessive production of destructive reactive oxygen species, coupled with a weakened antioxidant defence system. At the same time, microplastics impair the mitochondria — the cell’s energy centres — reducing the availability of ATP required for healthy neuronal function. “Over time, this energy deficit can lead to neuronal dysfunction and death,” the researchers write.
These mechanisms may help explain how microplastics could accelerate hallmark processes of Alzheimer’s disease, such as beta-amyloid and tau accumulation, and contribute to Parkinson’s pathology by promoting α-synuclein aggregation and damaging dopamine-producing neurons.
While direct causation has not yet been established, scientists say the growing evidence demands precautionary action. “Use less plastic, avoid plastic food containers and chopping boards, reduce processed foods, choose natural fibres, and minimise single-use plastics,” advised Dr. Keshav Raj Paudel, a co-author of the study.
The researchers emphasise that the findings should inform urgent policy interventions — from reducing plastic production and improving waste management to creating national frameworks for monitoring environmental contamination.
As microplastics now permeate the food we eat, the water we drink, and even the tissues of the human brain, experts warn that delaying action could expose future generations to an avoidable and potentially irreversible neurological health burden.
