Microplastics are quite literally everywhere scientists have looked: from remote islands to the depths of the Mariana Trench and in water, food, and air, it is basically everywhere humans exist. But they also exist in the human body, in the human brain, to be precise. And this comes at astronomical costs to our well-being. Microplastics are small plastic particles that are the result of plastic degradation. They have been detected in a variety of marine life, but also in drinking water and in some foods, such as honey and salt. Furthermore, exposure to microplastics can also occur through inhaled air. Plastics have invaded all corners of the world, including our kidneys, lungs, and other organs. Microplastics in the human body also have various effects, both discovered and yet to be discovered by scientists, on our health. Recent studies have been focusing particularly on their presence in our brain since it is the most vital organ of our body. In fact, Toxicologist Matthew Campen has estimated that he can glean about 10 grams of plastic from a donated human brain; that's roughly the weight of an unsharpened crayon. "Morbidly speaking, the best source I can think of to get good, relevant microplastics is to take an entire human brain and digest it," says Campen.
Additionally, microplastic quantities in the samples of brains from 2024 were about 50% higher in comparison with those from 2016. These brain samples contained up to 30 times more microplastics than samples from a person's kidneys and liver. A number of studies have found that exposure to microplastics and nanoplastics can cross the blood-brain barrier and induce neurotoxicity, the detrimental effect of chemicals on the brain, spinal cord, and peripheral nervous system's structure and function. It can lead to coordination and balance dysfunction, fatigue, headaches, muscle issues, and vision issues. Another study in January came to the conclusion that the plastics were ingested by immune cells and ended up clogging the small blood vessels in the brain.
Different studies also reached the conclusion that microplastics in human tissues like the brain can be linked with other issues like cancer, heart and kidney disease, Alzheimer's disease, or fertility issues in human beings. Though microplastics are involved in such issues, there is not enough evidence to ascertain that they are the primary cause. There are, nevertheless, research studies that confirm this fact, such as one published in March 2024, where it was indicated that nearly 60% of about 250 people undergoing heart surgery had micro- or nanoplastics in one of the main arteries.
Animal studies have provided preliminary evidence of the damage that microplastics can inflict on the brain. After being exposed to microplastics in the lab, rodents developed memory impairment, anxiety, and neuroinflammation. While human studies are in their infancy, researchers warn that long-term exposure could result in similar cognitive and behavioral issues. While the lasting effects of microplastic accumulation in the brain are not yet known, scientists are urging action today. Reducing plastic consumption, improving waste management, and investing in biodegradable materials are key steps to avoiding exposure. In the meantime, individuals can reduce their risk by consuming filtered water, eating foods that are not packaged in plastic, and reducing the use of single-use plastics. The discovery of microplastics in the brain is a tipping point for environmental health research. As scientists work to uncover the full extent of their impact, one thing is clear: plastic pollution is no longer just an environmental issue—it's a critical threat to human health.