Microplastics are found in food, water, air and household dust and can enter the brain through the weakened blood-brain barrier.[1][2] The new study identifies five main mechanisms of brain damage: activation of immune cells, increased oxidative stress, disruption of the blood-brain barrier, damage to mitochondria, and direct damage to neurons.[1][2] The weakened barrier allows the activation of immune cells and inflammatory molecules, which worsens the damage to her cells.[1][2] Microplastics disrupt energy production in mitochondria, thereby reducing ATP production, weakening neuronal activity and leading to damage to brain cells.[1][2] These mechanisms interact and increase the extent of damage.[1][2] A study links microplastics to Alzheimer's disease through increased accumulation of beta-amyloid and tau proteins, and to Parkinson's disease through α-synuclein aggregation and damage to dopaminergic neurons.[1][2] The concentration of microplastics in the human brain has increased by 50% in the last eight years (2016–2024), and the brain contains more of them than the kidneys or the liver.[4] In brain samples from 2024, microplastics made up an average of 0.5 percent of their weight.[8]