Study Explores Connection Between Microplastics and Neurodegenerative Diseases

A new review suggests that microplastics may play a role in the development or progression of neurodegenerative diseases such as Alzheimer’s and Parkinson’s. The study, published in Molecular and Cellular Biochemistry, identifies five biological pathways through which microplastics could cause inflammation and cellular damage in the brain.

Led by researchers from the University of Technology Sydney and Auburn University, the work underscores growing concerns about environmental pollutants and brain health. According to co-senior author Kamal Dua, adults may consume as much as 250 grams of microplastics each year. “We ingest microplastics from a wide range of sources including contaminated seafood, salt, processed foods, tea bags, plastic chopping boards, drinks in plastic bottles and food grown in contaminated soil, as well as plastic fibres from carpets, dust and synthetic clothing,” said Dua. 

Common types of microplastics include polyethylene, polypropylene, polystyrene, and polyethylene terephthalate (PET). Although much of this material is cleared from the body, evidence shows that some particles can accumulate in internal organs, including the brain. The researchers identified five main mechanisms of harm: including triggering immune cell activity, generating oxidative stress, disrupting the blood–brain barrier, impairing mitochondria and damaging neurons.

“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,” explained Dua. The immune response perceives microplastics as foreign material, setting off cycles of inflammation and oxidative stress. These effects are amplified when the brain encounters environmental toxins. 

Oxidative stress occurs when levels of reactive oxygen species rise and the body’s antioxidant defenses are overwhelmed. “Microplastics also interfere with the way mitochondria produce energy, reducing the supply of ATP, or adenosine triphosphate, which is the fuel cells need to function. This energy shortfall weakens neuron activity and can ultimately damage brain cells,” Dua said.

The paper also discusses potential links to hallmark processes in Alzheimer’s and Parkinson’s, including beta-amyloid and tau buildup, and alpha-synuclein aggregation. While direct causation has yet to be proven, the authors recommend reducing exposure to microplastics. “We need to change our habits and use less plastic,” said co-author Keshav Raj Paudel.