Study Reveals How Microplastics Potentially Impact Human Health

Humans and animals are often exposed to microplastics because they are in many substances. Some researchers wanted to understand the impact of microplastics and found the effects of exposure to these substances and how that may influence health outcomes—according to a recent study published in Environmental Health Perspectives, ingested microplastics spread from the gut to the brain, liver, and kidneys.

Findings suggest that exposure to microplastic can lead to metabolic changes within tissues, potentially having systemic effects. The implications of the findings for human health are substantial.  

Microplastics, including the soil, food, and water, have become conspicuous within the environment. The authors of this study define these microplastics as particles smaller than 5 millimeters. They wanted to find out how different microplastics influenced mice’s body organs. Researchers in this study attempted to replicate microplastic consumption in a quantity similar to human exposure.

Mice were exposed to various polystyrene through oral gastric feeding. After these mice were fed microplastics, researchers examined serum, brain, liver, kidney, and colon tissues to identify their presence of them. Researchers identified microplastics in multiple organs, including the brain, liver, and kidneys, in the exposed mice. These findings show how microplastics can spread to other distant body areas. 

After microplastic exposure, they also found that specific metabolic changes occurred in the colon, liver, and brain. These changes depended on how much exposure the mice received and what type of microplastic they were exposed to. Some doctors say that laboratory-dosed microplastics near the upper particle size limit for crossing gut epithelial layers are not only absorbed after ingestion but also deposited in organs. 

This research has its limitations. The researchers used mice for this study, which suggests that future studies need to be conducted to see if these findings apply to humans. Researchers utilized microplastics that did not contain chemical additives common in microplastics that may make consuming microplastics worse. Future research can consider how these chemicals may affect the impact of microplastics on people. 

The study did not investigate clearance rates of microplastics, which may influence their impact. Researchers only evaluated the prefrontal cortex of mice’s brains and couldn’t precisely note the microsphere location. Thus, it’s possible that microplastics didn’t cross the blood-brain barrier. 

Researchers further noted that their analysis of microplastics could have been improved. Future research can focus on better ways to identify and measure tissue microplastics and plasticizers.  

Journal Reference – Garcia, M. M., Romero, A. S., Merkley, S. D., Meyer-Hagen, J. L., Forbes, C., Hayek, E. E., … Castillo, E. F. (2024). Environmental Health Perspectives, 132(4). doi:10.1289/ehp13435