Plastic particles in F&B products harm human health, research finds

Microscopic plastic particles found in F&B may affect glucose metabolism and harm organs such as the liver, according to a new animal study. The findings, presented during the ongoing Nutrition 2025 conference (May 31–June 3), point to the need for more research.

The researchers gave mice a daily dose of polystyrene nanoparticles (<100 nm) in addition to their standard rodent diet. Polystyrene is a commonly used plastic in food packaging and products. 

Compared to the control group, the mice consuming nanoplastics showed systemic glucose intolerance and elevated alanine aminotransferase, which the team says indicates liver injury. 

“With the growing concern around micro- and nanoplastic exposure, we wanted to evaluate the impact of this exposure on health,” says Amy Parkhurst, a doctoral candidate in the laboratory of Fawaz George Haj, Ph.D., at the University of California (UC) Davis, US. 

“Our observations — that oral ingestion of polystyrene nanoplastics contributes to glucose intolerance and signs of liver injury — confirm and extend what has been recently reported on the effects of nanoplastics in animal models.”

The research was presented at Nutrition 2025 in Orlando, US, the annual meeting of the American Society for Nutrition.

Gut and liver impact

For the study, the researchers administered 12-week-old male mice a daily oral dose of 60 mg per kg of body weight of polystyrene nanoparticles for seven weeks. This dose is based on human exposure levels, and earlier mouse studies showed health effects at similar amounts. 

“We can’t control for all the plastics the mice are exposed to,” says Parkhurst. “However, our study design allowed us to see dose-correlated changes since the nanoplastics-dosed group would have a higher exposure.”

The researchers performed glucose tolerance, endotoxin, and gut permeability tests between weeks six and seven of exposure.

In addition to impacting glucose intolerance and indicating liver injury, the researchers also observed an increase in gut permeability and elevated endotoxin levels in the mice consuming polystyrene. These factors contribute to liver dysfunction. 

Research estimates that a person may ingest 40,000 to 50,000 microplastic particles per year through F&B intake.“Our findings warrant further studies to help inform policy around micro- and nanoplastics,” adds Parkhurst. “Robust scientific evidence plays a key role in shaping monitoring efforts and guiding regulations.”

The researchers continue to study the impact of nanoplastics on other tissues, such as kidney function. The team aims to perform more rodent model studies to determine which tissues and organs are affected by nanoplastics and what underlying molecular mechanisms are involved. 

In addition, the researchers are collaborating with UC Davis researchers to use mass spectrometry imaging for high-resolution monitoring of the accumulation of nanoplastics in tissues and how this may affect metabolic changes. 

Microplastic consumption

Plastic breaks down into nano- and microparticles (<5 mm), which can enter the food chain. Nanoparticles are small enough to traverse through the human gut and respiratory systems. 

The researchers point to studies estimating that a person may ingest around 40,000 to 50,000 microplastic particles per year through F&B, while some estimates amount to ten million particles annually. 

Last week, researchers warned that microplastics are accumulating in agricultural soils at a significantly higher rate than in oceans, estimating that farms hold 23 times more microplastics than seas. 

Meanwhile, a US study discovered an average of 240,000 detectable nanoplastic fragments per liter of bottled water. The authors note that this count is ten to a hundred times higher than earlier estimates, which focused on larger plastic particles. 

Scientists are also exploring methods to counter the adverse health effects of plastics. For example, one review suggests that probiotics may overcome some toxicities associated with polystyrene particles in humans. However, the authors cautioned that the benefits of these probiotics would need to be validated in clinical research.