They’re in bottled water. They’re in human brains and aortas. Now, scientists say microplastics have also been found in chewing gum.
A strip can release hundreds to thousands into human saliva to potentially be ingested.
“Our goal is not to alarm anybody,” Dr. Sanjay Mohanty, an engineering professor at UCLA, said in a statement. “Scientists don’t know if microplastics are unsafe to us or not. There are no human trials. But we know we are exposed to plastics in everyday life, and that’s what we wanted to examine here.”
Mohanty was the project’s principal investigator, which was presented Tuesday at the spring meeting of the American Chemical Society.
The researchers note that scientists estimate humans consume tens of thousands of microplastics every year.
Microplastics are minuscule pieces of plastic debris that are less than five millimeters long. They come from a variety of sources, including from larger debris that degrades into smaller pieces over time. The particles are now understood to be pervasive throughout Earth’s environment, and humans are exposed through animal products, plastic ware, water and even air.
The full extent of costs to human health remains shrouded in mystery, but they’ve been linked to an increased risk of heart disease and could be tied to dementia.
Chewing gum as a potential source of microplastics has yet to be widely studied. They’re made from a rubbery base, sweetener, flavorings, and other ingredients. Natural gum products are made using a plant-based chemical compound, and other products use synthetic rubber bases from ones that are petroleum-based.
“Our initial hypothesis was that the synthetic gums would have a lot more microplastics because the base is a type of plastic,” explained Lisa Lowe, a graduate student in Mohanty’s lab.
They tested five brands of commercially-available synthetic and natural gum, respectively. The brands were not identified.
Seven pieces from each brand were chewed by one person. Each piece was chewed for four minutes, leading to saliva production every 30 seconds. Then, they rinsed their mouth with clean water. They also collected samples of saliva over 20 minutes, to better understand the rate at which microplastics were released. They measured the level of microplastics collected in each sample, counting them under a microscope or analyzing them using spectroscopy.
They measured an average of 100 microplastics released per gram of gum, although some released six times as much.
Because a typical piece of gum weighs between two and six grams, they said a large piece of gum could release as many as 3,000 plastic particles.
If a person chews between 160 and 180 small sticks annually, they could ingest around 30,000 microplastics.
Most microplastics were released in the first two minutes of chewing, which helps pieces flake off. By just eight minutes, 94 percent of the particles collected during the tests were released. However, they noted, even smaller particles were not detected because the study was limited to identifying those 20 micrometers wide or larger.
“The plastic released into saliva is a small fraction of the plastic that’s in the gum,” said Mohanty. “So, be mindful about the environment and don’t just throw it outside or stick it to a gum wall.”
What’s a gum-chewer to do?
To reduce potential exposure to microplastics, they should chew one longer, the researchers said.
