NEURO NEWS

A new study reveals microplastics may play a role in worsening neurodegenerative disorders such as Alzheimer’s and Parkinson’s. Researchers warn that if microplastics can intensify or speed up these conditions, the impact on public health could be substantial.

Pharmaceutical scientist Associate Professor Kamal Dua from the University of Technology Sydney explained that adults are thought to ingest about 250 grams of microplastics each year, which is enough to cover a dinner plate.

“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 fibers from carpets, dust, and synthetic clothing.

“Common plastics include polyethylene, polypropylene, polystyrene, and polyethylene terephthalate or PET. The majority of these microplastics are cleared from our bodies, however, studies show they do accumulate in our organs, including our brains.”

The new review, published in Molecular and Cellular Biochemistry, brings together work from an international team of scientists based at the University of Technology Sydney and Auburn University in the United States.

Their analysis outlines five key biological routes through which microplastics may negatively affect the brain. These include activating immune cells, increasing oxidative stress, weakening the blood–brain barrier, interfering with mitochondrial function, and causing direct injury to 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,” said Associate Professor Dua.

“The body treats microplastics as foreign intruders, which prompts the brain’s immune cells to attack them. When the brain is stressed by factors like toxins or environmental pollutants, this also causes oxidative stress,” he said.

Microplastics cause oxidative stress in two main ways: they increase the amount of “reactive oxygen species” or unstable molecules that can damage cells, and they weaken the body’s antioxidant systems, which normally help keep those molecules in check.

“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,” said Associate Professor Dua. “All these pathways interact with each other to increase damage in the brain.”

The study also explores specific ways in which microplastics could contribute to Alzheimer’s, including triggering increased buildup of beta-amyloid and tau; and in Parkinson’s through aggregation of α-Synuclein and damage to dopaminergic neurons.

“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,” said Dr. Paudel.

The researchers hope the current findings will help shape environmental policies to cut plastic production, improve waste management, and reduce long-term public health risks posed by this ubiquitous environmental pollutant.

Earlier this year, other research revealed that microplastics are more likely to be found in the brain than in any other part of the body. The average amount, 4,800 micrograms per gram of microplastics in brain tissue, was found to be the same as the amount found in a standard plastic spoon, according to the study published in Nature Medicine.