Invisible plastic particles lurking in everyday meals may be sabotaging the brain’s defenses against Alzheimer’s and Parkinson’s. A systematic review led by the University of Technology Sydney and Auburn University now outlines five cellular routes by which these fragments could, in theory, nudge the nervous system toward the pathological signatures of the two diseases.
Using published animal and cell-culture data, the team traced microplastics from the gut to the bloodstream and, finally, across a blood–brain barrier that microplastics are hypothesized to render “leaky.” Once inside, the particles may activate immune cells, trigger oxidative stress, impair mitochondria, and directly injure neurons.
These events, taken together, are proposed to foster the protein clumping central to Alzheimer’s (β-amyloid and tau) and Parkinson’s (α-synuclein), although human neuropathological proof is still missing.
Adults are estimated to ingest roughly 250 g of microplastics each year—about the area of a dinner plate—through “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,” explains Associate Professor Kamal Dua of the University of Technology Sydney. The review, appearing in Molecular and Cellular Biochemistry, is co-authored by Master’s student Alexander Chi Wang Siu.
Microplastics “actually weaken the blood-brain barrier, making it leaky,” Dua adds. “Once that happens, immune cells and inflammatory molecules are activated, which then causes even more damage to the barrier’s cells.” Yet the authors stress that the pathways remain speculative; no longitudinal human data link routine plastic exposure to neurodegeneration.
The paper therefore calls for large epidemiological studies before any public-health guidance can be framed. Until such evidence emerges, the proposed connection between microplastic intake and heightened risk of Alzheimer’s or Parkinson’s stays firmly in the realm of hypothesis.
Source: Sciencedaily