WEB DESK: Tiny, nearly invisible fragments of plastic—known as microplastics—have recently been discovered accumulating within human brains. Although the presence of these particles has been confirmed, scientists are still unsure whether they cause any harm.
Microplastics are pervasive, found floating in the atmosphere, carried across oceans, and present in the food and water we consume. They’ve been detected throughout human bodies—including in lungs, hearts, placentas, and even crossing the blood-brain barrier. Their widespread distribution has become a focal point in ongoing negotiations for a global plastic pollution treaty, with the latest UN discussions taking place in Geneva next week.
The health implications of microplastics and their tinier counterparts, nanoplastics, remain unclear. Researchers are actively exploring their potential effects, but this is a relatively new area of investigation. One notable study published in Nature Medicine in February examined brain tissue samples from 28 individuals who died in 2016 and 24 who died recently in New Mexico. The researchers found increasing amounts of microplastics in these samples over time.
The study garnered worldwide attention when lead researcher Matthew Campen, a US toxicologist, stated that they had detected what equates to a plastic spoon’s worth of microplastics in the human brain. He estimated that about 10 grams of plastic could be isolated from a donated brain—comparable to an unused crayon in size.
However, many experts urge caution. “While the findings are intriguing, they should be interpreted carefully until confirmed independently,” said Theodore Henry, a toxicologist at Heriot-Watt University in Scotland. He emphasized that the current evidence does not support claims about the health effects of microplastics in the brain.
Oliver Jones, a chemistry professor at RMIT University in Australia, pointed out that the data are limited and that it’s unlikely for brains to contain more microplastics than found in raw sewage. He noted that the study participants were healthy before death, and the researchers acknowledged insufficient data to determine whether microplastics caused harm.Additionally, some issues have been raised about the study’s methodology, such as duplicated images, though experts say this does not undermine the core findings.
Most existing research remains observational, unable to establish direct cause-and-effect relationships. For example, a study in the New England Journal of Medicine linked microplastics in blood vessels to higher risks of heart attack, stroke, and mortality in patients with arterial disease. Experiments on mice, published in Science Advances, demonstrated that microplastics could cause blood clots in the brain by obstructing cells—a finding that, while noteworthy, may not directly translate to humans due to biological differences.
A 2022 review by the World Health Organization concluded that current evidence is insufficient to assess the risks microplastics pose to human health. Nonetheless, many health experts advocate for a precautionary approach, emphasizing the need for immediate action to mitigate potential risks.
A recent report from the Barcelona Institute for Global Health, ahead of international treaty negotiations, stressed that “policy decisions cannot wait for complete data.” It called for measures to limit exposure, improve risk assessment methodologies, and protect vulnerable populations—acknowledging that delaying action could lead to a broader public health crisis.
Meanwhile, global plastic production has doubled since 2000 and is projected to triple by 2060, underscoring the urgency of addressing this mounting environmental and health challenge
