Plastic is everywhere — from the oceans to the bloodstream. Now, new research presented at the NUTRITION 2025 conference in Orlando suggests that the tiniest plastic fragments—nanoplastics—could be silently harming your liver and disrupting your metabolism. Plastics are part of the food we eat, the animals and plants we eat, the water we drink and are emitted from plastic teeth aligners and bubble gum.
In a new animal study, scientists at the University of California, Davis, found that ingesting polystyrene nanoplastics (commonly found in food packaging) led to glucose intolerance, liver damage, and gut barrier disruption in mice. These alarming results echo concerns raised in earlier Green Prophet reporting on microplastic pollution in sea salt, seafood, and even the placentas of unborn babies.
“We already know microplastics have invaded every corner of the food chain,” said Amy Parkhurst, the study’s lead author and a Clinical and Translational Science Center fellow. “But now we’re seeing how those particles can impact basic bodily functions—like regulating blood sugar.”
Nanoplastics are the breakdown products of everyday plastics—smaller than 100 nanometers. They’re invisible to the naked eye, but not to our bodies. Previous research cited by Green Prophet estimated that an average person may consume 40,000 to 50,000 plastic particles per year—others put the number closer to 10 million particles annually.
The UC Davis study focused on male mice, fed a normal diet alongside a daily oral dose of polystyrene nanoparticles mimicking human exposure. The mice developed signs of systemic glucose intolerance, a red flag for type 2 diabetes. They also showed elevated levels of alanine aminotransferase, a marker for liver injury.
Perhaps more worrying: the study found increased gut permeability, which allowed endotoxins to leak into the bloodstream—creating a toxic loop that may contribute to chronic liver dysfunction.
This new evidence builds on prior warnings that our plastic obsession could come with a steep biological price. From endocrine disruption to cognitive decline, microplastics have been linked to a spectrum of emerging health risks.
This latest study adds a metabolic twist—suggesting that nanoplastics could directly interfere with how our bodies process sugar, potentially increasing risks of obesity and diabetes.
Parkhurst and her colleagues are now working with UC Davis’s Dr. Elizabeth Neumann to map the tissue-level effects of nanoplastics using mass spectrometry imaging. Their goal? To understand where nanoplastics end up in the body—and how they alter metabolism at the molecular level.
“We need more science before setting policy,” said Parkhurst. “But the early warning signs are there.”
That warning should matter to policymakers, consumers, and health advocates alike. As science catches up with the scale of plastic pollution, the push for bans on single-use plastics and improved biodegradable alternatives is gaining urgency.
Next time you reach for a plastic-wrapped snack or sip from a disposable cup, remember: the real cost may not show up on the price tag, but in your liver enzymes or your glucose test.
