In recent years, exposure to microplastics has become a growing concern for human and environmental health. Microplastics, defined as plastic particles smaller than 5 mm, have been detected in various ecosystems, in drinking water, in food and even in the human body. Recent studies suggest that these particles may accumulate in the brain, raising questions about their potential role in the onset and progression of dementia. Microplastics can enter the body through ingestion and inhalation, overcoming biological barriers thanks to their small size. A study published a few months ago proved that they can even enter the olfactory bulb, solubilize in the myelin of nerve structures and release the monomers or small molecular aggregates that constitute them.
Experimental studies have shown that nanoplastic particles can cross the blood-brain barrier (BBB), a tissue that protects the brain from toxic substances. Once inside the central nervous system, microplastics could trigger inflammatory responses and oxidative stress, two processes known to contribute to neurodegeneration. A recent study published in Environmental Science & Technology has shown that chronic exposure to microplastics in animal models leads to increased neuroinflammation and an accumulation of toxic proteins, similar to those associated with Alzheimer’s disease. Furthermore, researchers observed an alteration in the function of glial cells, which play a crucial role in maintaining neuronal homeostasis and protecting against neurotoxins.
In addition to direct neurotoxic effects, microplastics could interact with other harmful substances, such as heavy metals persistent organic pollutants (POPs) and regulkar plasticizers, increasing their damaging effect on the brain. Some studies suggest that the presence of microplastics in brain tissue could aggravate cognitive decline, contributing to the acceleration of neurodegenerative diseases such as Parkinson’s disease and senile dementia. Despite emerging evidence, the relationship between microplastics and dementia remains poorly understood. Longitudinal studies on human subjects are needed to determine the level of exposure that could pose a significant risk to cognitive health.
In the meantime, exposure reduction strategies, such as the use of alternative materials to plastic and improved water filtration systems, could represent preventive measures to reduce the impact of microplastics on the human brain.
- Edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.
Scientific references
Leslie HA et al. (2022). Environment Int. 163:107199.
Campanale C et al. (2020). Int J Envir Res Public Health, 17(4):1212.
Prüst M et al. (2020). Particle Fibre Toxicology, 17:24.
Cox KD, Covernton GA et al. (2019). Envir Sci Technol. 53(12):7068.
