Microplastics and Forever Chemicals: Why Your Body Can't Detox Them — and What It Actually Needs — The brain infiltration

The 2025 Nihart et al. study in Nature Medicine did something that hadn&#8217;t been done before: it quantified microplastics in human brain tissue from autopsy samples. Every brain had them. The concentrations had been climbing over time. And in the brains of people who had been diagnosed with dementia, microplastic concentrations were up to 10 times higher than in controls. The mechanism of entry mirrors the gut: nanoparticles compromise the blood-brain barrier through ROS-mediated degradation of the exact same tight junction proteins &#8212; ZO-1, occludin, claudin. Once inside, they accumulate preferentially in fat-rich tissues, which is why the myelin sheath of neurons becomes a primary storage site. The downstream damage operates through four converging pathways. First, mitochondrial ROS production inside neurons inhibits Complex I of the electron transport chain &#8212; the same biochemistry we see with Parkinson&#8217;s toxins like MPTP and rotenone. Second, microglial activation shifts from protective to pro-inflammatory, with NLRP3 inflammasome engagement and chronic cytokine release. Third, the particles themselves serve as physical scaffolds that nucleate amyloid-&#946; and &#945;-synuclein aggregation &#8212; seeding the exact protein misfolding events that drive Alzheimer&#8217;s and Parkinson&#8217;s. Fourth, the same particles carry heavy metals and persistent o