Microplastics Reach Mice Brains Within Weeks — What That Could Mean for Human Health

Microplastics Migrate From Gut to Brain in Just Weeks

A new study published in Environmental Health Perspectives found that microplastics given to mice in drinking water migrated from the gut into the liver, kidneys and even the brain in as little as four weeks. Researchers say the exposure levels used in the experiment were comparable to concentrations humans may encounter in drinking water.

'We could detect microplastics in certain tissues after the exposure,' said Eliseo Castillo, an associate professor at the University of New Mexico and a co-author of the study. 'That tells us it can cross the intestinal barrier and infiltrate into other tissues.'

The team also reported measurable metabolic changes in the colons, livers and brains of exposed animals. Because mice have short lifespans, scientists said seeing changes after only weeks of exposure raises concerns about the potential effects of chronic, lifetime exposure in people.

What We Do — And Don't — Know

What we know: Microplastics are defined as particles smaller than five millimeters and have been detected widely in the environment, including the air and drinking water. This study shows these particles can move beyond the gut into internal organs within weeks under laboratory conditions.

What we don't know: The research does not prove direct health outcomes in humans. While other studies have associated microplastic exposure with conditions ranging from inflammation to reproductive issues, dementia and cancer, causal links and the mechanisms behind those associations remain under investigation.

Path Forward and Practical Steps

Researchers say these findings can help map how mixed microplastic exposures affect different tissues and inform risk assessments. Scientists are also developing ways to remove microplastics from drinking water: a team at Tarleton State University is studying plant-derived molecules as a treatment approach, while researchers at the Indian Institute of Science developed a hydrogel that can remove more than 90% of polyvinyl chloride (PVC) and polypropylene particles in tests.

On an individual level, reducing plastic use and switching to alternatives can help lower everyday exposure: choose products with non-plastic packaging, use reusable silicone food containers, metal razors and seek out detergents sold in plastic-free packaging when possible.

Bottom line: The study adds to growing evidence that microplastics can penetrate body tissues quickly in animals and underscores the need for further research on long-term human health effects and effective water-treatment solutions.