A new systematic review indicates that microplastics could trigger brain inflammation and damage through several biological pathways, potentially worsening neurodegenerative diseases like Alzheimer's and Parkinson's. Researchers from the University of Technology Sydney and Auburn University identified five mechanisms linking these tiny plastic particles to brain health risks. Adults ingest about 250 grams of microplastics annually from various everyday sources.
Microplastics, tiny fragments of plastic found in food, water, and household dust, may pose a threat to brain health, according to a systematic review published in Molecular and Cellular Biochemistry. The study, led by scientists from the University of Technology Sydney (UTS) and Auburn University, outlines five biological pathways through which these particles could cause inflammation and neuronal damage.
The pathways include activation of immune cells, increased oxidative stress, disruption of the blood-brain barrier, interference with mitochondrial function, and direct neuron damage. Associate Professor Kamal Dua from UTS explained, "Microplastics actually weaken the blood-brain barrier, making it leaky. Once that happens, immune cells and inflammatory molecules are activated, which then causes even more damage to the barrier's cells."
Oxidative stress from microplastics arises in two ways: by elevating reactive oxygen species, which harm cells, and by impairing the body's antioxidant defenses. Additionally, these particles disrupt mitochondria, reducing ATP production essential for cell function. This energy deficit can impair neuron activity and lead to brain cell damage. The pathways interact, amplifying overall harm.
In relation to specific diseases, the review suggests microplastics may promote beta-amyloid and tau protein buildup in Alzheimer's and encourage α-Synuclein aggregation and harm to dopaminergic neurons in Parkinson's. Dementia currently affects over 57 million people globally, with cases of Alzheimer's and Parkinson's expected to rise.
First author Alexander Chi Wang Siu, a UTS Master's student, is collaborating with Professor Murali Dhanasekaran at Auburn, along with UTS colleagues Dr. Keshav Raj Paudel and Professor Brian Oliver. Previous UTS research has explored microplastic inhalation and lung effects.
While a direct causal link requires further study, the authors urge reducing exposure. Dr. Paudel advised, "We need to change our habits and use less plastic. Steer clear of plastic containers and plastic cutting boards, don't use the dryer, choose natural fibers instead of synthetic ones and eat less processed and packaged foods."
Common microplastics include polyethylene, polypropylene, polystyrene, and PET, ingested via contaminated seafood, salt, processed foods, tea bags, plastic bottles, and synthetic fibers. Most are excreted, but some accumulate in organs, including the brain.
