Are Microplastics Affecting Our Brain Health? How One Mass General Brigham Epidemiologist is Working to Find Answers
With the global production of plastics increasing exponentially in recent decades, there are new concerns about the long-term health risks of exposure to microplastics—the tiny particles of plastic in the environment that can be inhaled or absorbed into the body.
In a recent study, researchers from the University of New Mexico analyzed human postmortem brain, liver and tissue samples from autopsies and confirmed the presence of microplastics in all three organs, with brains having the highest concentrations of plastics (on average about 10 times higher than the lungs or the kidneys).
What’s also notable is that levels of microplastics in these organs seem to be increasing over time. Samples collected from 2024 had more microplastics than those collected in 2016.
While these findings have raised some alarms, they also highlighted many unanswered questions. For example, how much are different populations exposed to microplastics? How do microplastics enter and accumulate in the human brain over time, and what impact do they have on brain health?
Jun Li, MD, PhD
Jun Li, MD, PhD, an epidemiologist at Mass General Brigham, is preparing to tackle some of those questions in collaboration with researchers at the University of New Mexico and others.
Trained in molecular and systems epidemiology, Li plans to use large population-based studies to evaluate microplastic exposure levels in the brain and whether they are associated with cognitive disorders and other brain health issues.
For Li, the significance of this research lies in its potential to inform prevention on a large scale. Her work is rooted in population health, with an emphasis on understanding disease in ways that are relevant beyond individual cases.
A Research Career Shaped by Personal Experience
Li’s longstanding interest in population health and disease prevention was sparked by a family member’s experience with diabetes and its complications.
She received her medical training in preventative medicine before going on to pursue a PhD in cardiometabolic disease, epidemiology and environmental health.
After completing her PhD, Li continued her postdoctoral training at the Harvard T. H. Chan School of Public Health. During her doctoral and postdoctoral work, she began incorporating molecular profiling techniques into epidemiological studies, an approach that was still emerging at the time.
By integrating metabolomics, proteomics, genetics, and gut microbiome data into population health research, Li has been able to study disease and potential biological pathways at the system level.
That framework positioned her to investigate the role of new and understudied environmental exposures such as microplastics.
“The more I learn and conduct research, the more fascinating it becomes,” she says. “There are endless important questions that we still don’t know the answers to.”
Current and Upcoming Research
Li’s recent work has explored circulating metabolites, genetic, and lifestyle factors associated with Type 2 diabetes, the host-gut microbiome cross-talk in dietary metabolism, and the molecular link between diet and dementia. While she continues to pursue these projects, she is now expanding her work to investigate microplastics as an emerging environmental exposure with potential neurological implications.
“We don’t know what the general microplastics burden looks like in the population,” she explains. “We also don’t know whether microplastic levels are related to geography or demographic status, or their clinical implications.”
Li also plans to incorporate her skills in molecular epidemiology to investigate the inflammatory and metabolic changes that are associated with exposure to microplastics and how these changes impact brain health. This proposed work, which includes collaboration with the RUSH University Alzheimer’s Disease Research Center and the University of New Mexico, reflects Li’s broader commitment to studying health at the population level.
As her research continues to evolve, Li remains guided by curiosity, rigor, and a belief that meaningful discoveries emerge when scientists pursue important questions persistently and rigorously, despite challenges and uncertainty.
“We want to understand the causes of disease better so that we can prevent it and treat it better for everyone,” she says.
Subscribe to BenchMarks!
Subscribe to our monthly research newsletter and be the first to know what’s shaking in science at Mass General Brigham. From groundbreaking discoveries to the latest “you-heard-it-here-first” breakthroughs, we’ve got the updates that’ll keep your curiosity grooving.