In recent years, several scientific studies have shown the presence of microplastics in the lungs, the heart, the liver, the kidneys, or even in the placenta and the blood. Recently, their presence in the brain worries. And with it, the question of knowing the damage they can cause. To what extent can the accumulation of these particles degrade our nervous system?
Scientists are still far from being able to provide an answer but the question is at the center of a lot of research. The subject is so worrying that he is at the heart of the negotiations that reopen Tuesday in Geneva to lead to a treaty against plastic pollution.
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Upward trend
At the start of the year, a study published in Nature Medicine had made a lot of noise by daring to expose the exposure of our brains to microplastics. The researchers had come to the conclusion of a “upward trend in microplastic concentration in the brain and liver“. Made from the autopsy of around fifty people who died in the American state of the New Mexico, part of the sample was dead in 2016 and the other in 2024, the study concluded that the systematic presence of microplastics in the brain, as well as a clear increase between the two dates.
In terms of quantity, a brain could contain the equivalent of a teaspoon of microplastics, according to Matthew Capen, principal researcher of the study. The American toxicologist had also estimated that researchers could extract approximately 10 grams of plastic from a removed brain. A figure that has enough to mark the spirits, even if some scientists want to be more cautious, stressing that the study was only carried out on a small number of people, a fortiori from the same geographical area. “”Even if these are interesting results, they must be interpreted with cautionthe researcher Theodore Henry, a specialist in environmental toxicology at AFP at AFP at the Scottish University Heriot-Watt. At this stage, speculation about possible health effects venture far beyond the evidence“. Prudence also remains in order to Oliver Jones, professor of chemistry at the Australian University Rmit:”If – and it is a big if in my opinion – there are microplastics in our brain, there is currently no evidence of harm“.
Heart crisis, stroke, thrombosis …
However, this does not prevent a number of researchers from considering that this study largely justifies to question the effects of microplastics on our brain, while, in recent years, the first elements on other health risks have been highlighted. Thus, a study published in 2024 in the New England Journal of Medicine She showed an association between the accumulation of these particles in blood vessels and an increased risk of heart attack, stroke, even death, in some people with atherosclerosis, a disease affecting the arteries.
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If, at present, no study of this type has been carried out for the brain and, more broadly, the neurological risks associated with microplastics in humans, toxicologists nevertheless call for the precautionary principle, citing the example of other types of pollution such as that with fine particles in air. “”What is worrying for the brain is that fine particles are the chemical component of the exhibition “that is to say all the environmental factors to which a person is exposed, “which is most associated with Alzheimer’s disease“, Underlines the French toxicologist Xavier Coumoul, professor at Paris Cité University. We could assume that the same goes for microplastics, even if it is not necessarily the case insofar as”fine particles are of a completely different natureas Mr. Cumoul points out.
Be that as it may, we agree that this hypothesis deserves more research, and in particular experiences on animals like mice. Among the first studies carried out at this level, one of them, carried out in China and published in January in the journal Science Advanceshighlighted in mice the deleterious effects of microplastics whose presence was detected live in the brain by advanced imaging techniques. These microplastics “can cause brain thromboses […] and generate neurocomportal disorders“, had concluded the authors.
