Microscopic plastic particles found in food and beverages may affect glucose metabolism and harm organs such as the liver, according to a new animal study.
The findings raise concerns about potential health risks in people who consume microplastics (less than 5 millimetre) and nanoplastics (less than 100 nanometre), which can enter the food chain and end up in seafood and other foods people eat.
Previous estimates show that a person may ingest around 40,000 to 50,000 microplastic particles a year through food and beverages, with some estimating exposure to be as high as 10 million particles per year.
“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,” said Amy Parkhurst, a doctoral candidate at the University of California, Davis, US.
For the study, the researchers focused on exposure via oral consumption to mimic nanoparticles found in food and drink.
They gave 12-week-old male mice a standard rodent diet with a daily oral dose of polystyrene nanoparticles. Polystyrene is a widely used plastic commonly found in food packaging and products.
The researchers chose a daily nanoparticle dose of 60 mg per kilogram of body weight, based on human exposure levels and earlier mouse studies that showed health effects at similar amounts.
“We can’t control for all the plastics the mice are exposed to,” said Parkhurst. “However, our study design allowed us to see dose-correlated changes since the nanoplastics-dosed group would have a higher exposure.”
Compared to the control group receiving no polystyrene, the mice consuming nanoplastics exhibited systemic glucose intolerance and elevated alanine aminotransferase, which indicates liver injury.
In the mice consuming polystyrene, the researchers also observed an increase in gut permeability and elevated levels of endotoxin, which contribute to liver dysfunction.
“Our findings warrant further studies to help inform policy around micro and nanoplastics,” said Parkhurst.
The findings will be presented at the ongoing NUTRITION 2025, the flagship annual meeting of the American Society for Nutrition in Orlando. (IANS)
