Plastic is in our clothes, cars, mobile phones, water bottles and food containers, but new research is adding to growing concerns about the impact of tiny plastic fragments on our health.
A study from the USA has for the first time detected microplastics in the human brain. The study, which has yet to be independently confirmed by other scientists, has been described in the media as frightening, shocking and alarming.
But what exactly are microplastic particles? What impact do they have on our health? Should we be worried?
What is microplastic? Can you see it?
We often think of plastic items as indestructible. But plastic breaks down into smaller particles. Definitions vary, but in general, microplastics are smaller than five millimeters.
This means that some pieces of microplastic are so small that they cannot be seen with the naked eye. Many of the images that the media uses to illustrate articles about microplastics are therefore misleading, as some of them show much larger, clearly visible pieces.
Microplastics have been found in many drinking water sources and everyday foods, meaning we are constantly exposed to them through our diet.
Such widespread, chronic (long-term) exposure poses a serious problem for human health. Although research into the potential risks posed by microplastics to our health is limited, it is increasing.
How about this latest study?
The study examined the concentrations of microplastics in 51 samples from men and women collected during routine autopsies in Albuquerque, New Mexico. The samples came from the liver, kidney and brain.
Because of their size, these tiny particles are difficult to study even with a high-powered microscope. So instead of trying to see them, researchers are starting to use complex instruments that determine the chemical composition of microplastics in a sample. This is the technique used in this study.
The researchers were surprised to find up to 30 times more microplastics in brain samples than in liver and kidney.
They suspected that this could be due to high blood flow to the brain (and thus carrying plastic particles with it). Alternatively, the liver and kidneys could be better able to deal with external toxins and particles. We also know that the brain does not undergo as much cell turnover as other organs in the body, which could cause the plastic particles to get stuck here.
The researchers also found that the amount of plastics in brain samples increased by about 50% between 2016 and 2024. This could be due to increasing plastic pollution and increased human exposure.
The microplastic particles found in this study were mostly made of polyethylene. This is the most commonly produced plastic in the world and is used for many everyday products such as bottle caps and plastic bags.
This is the first time microplastics have been found in the human brain, which is important. However, this study is a “pre-print,” meaning other independent microplastics researchers have not yet reviewed or validated the study.
How do microplastics get into the brain?
Microplastics typically enter the body through contaminated food and water. They can disrupt the gut microbiome (the community of microbes in the gut) and cause inflammation. This has an impact on the entire body via the immune system and the complex, two-way communication system between the gut and the brain. This so-called gut-brain axis is involved in many aspects of health and disease.
We can also inhale microplastics in the air. Once in the intestines or lungs, these particles can enter the bloodstream and then travel through the body to various organs.
Studies have found microplastics in human feces, joints, livers, reproductive organs, blood, vessels and hearts.
Microplastics also migrate into the brains of wild fish. In studies with mice, ingested microplastics are absorbed from the intestines into the blood and can reach the brain and become lodged in other organs along the way.
To reach brain tissue, microplastic particles must overcome the blood-brain barrier, a complex layer of cells designed to prevent substances from the blood from entering the brain.
While this is concerning, it is not surprising, as microplastics must overcome similar cellular barriers to enter the urine, testes and placenta, where they have already been detected in humans.
Is this a health risk?
The effects of microplastics on the human brain are not yet known. Some laboratory experiments suggest that microplastics increase inflammation and cell damage in the brain, alter gene expression, and change brain structure.
Aside from the effects of the microplastic particles themselves, microplastics can also pose risks when they transport environmental toxins or bacteria into and around the body.
In addition, various plastic chemicals could enter the body from the microplastic particles. These include the well-known hormone-disrupting chemicals BPA.
However, microplastics and their effects are difficult to study. Aside from their small size, there are so many different types of plastics in the environment. More than 13,000 different chemicals have already been identified in plastic products, and new ones are added every year.
In addition, microplastic particles are subject to decomposition by the environment and digestive processes, which is difficult to reproduce in the laboratory.
One goal of our research is to understand how these factors alter the behavior of microplastics in the body. We want to investigate whether improving the intestinal barrier through diet or probiotics can prevent the absorption of microplastics from the intestine into the bloodstream. This could effectively prevent the particles from circulating in the body and becoming lodged in organs.
How do I minimize my risk?
Microplastics are widespread in the environment and it is difficult to avoid contact with them. We are only just beginning to understand how microplastics can affect our health.
Until we have more scientific evidence, the best we can do is reduce our contact with plastics as much as possible and produce less plastic waste so that less of it ends up in the environment.
A simple way to start is to avoid foods and drinks packaged in single-use plastic or reheated in plastic containers. We can also minimize contact with synthetic fibers in our homes and clothing.
Sarah Hellewell, Senior Research Associate at the Perron Institute for Neurological and Translational Science and Research Fellow in the Faculty of Health Sciences, Curtin University; Anastazja Gorecki, Teaching and Research Fellow in the School of Health Sciences, University of Notre Dame in Australia; and Charlotte Sofield, PhD student in microplastics and gut/brain health at the University of Notre Dame in Australia.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
