Chewing gum might seem harmless, but new scientific findings suggest it could be a surprising source of microplastic exposure. Researchers have discovered that with every chew, individuals may be unknowingly releasing tiny plastic particles into their saliva—raising concerns about everyday microplastic intake.
Key Highlights:
- Recent research indicates that chewing gum can release hundreds, and potentially thousands, of microplastic particles into saliva, which may subsequently be absorbed into the body.
- Surprisingly, even gums marketed as “all-natural” were found to shed microplastics during chewing.
- Experts suggest that to minimize microplastic exposure from gum, it is better to chew a single piece for a longer period rather than continuously popping new ones.
A New Source of Microplastics: Chewing Gum Under Scrutiny
Concerns about microplastic pollution have mostly centered around oceans, food packaging, and bottled water. However, scientists are now pointing to an everyday habit that might add to our plastic intake: chewing gum. According to new research that will be presented at the American Chemical Society’s Spring 2025 meeting in San Diego, chewing even a single piece of gum could release hundreds—or even thousands—of microplastic particles into the saliva, many of which may be swallowed and absorbed into the body.
“Our goal is not to alarm anybody,” explained Sanjay Mohanty, PhD, senior author of the study and an associate professor of civil and environmental engineering at UCLA, in a press release. “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.”
Although the long-term health impacts of microplastics on humans remain under investigation, the very presence of plastics inside the body is enough to raise concern among health experts.
Potential Health Risks of Microplastic Exposure
While definitive proof is still pending, some experts caution against complacency. “What we know about microplastics themselves leads us to believe that they could be associated with negative health outcomes,” said Linda Kahn, PhD, MPH, an assistant professor of population health at the NYU Grossman School of Medicine in New York City.
Previous studies have linked microplastics to an array of health concerns, such as respiratory issues, lung cancer, impaired fertility, and reduced birth weights. However, these studies generally show associations rather than direct causation, meaning that while there is evidence of a connection, scientists cannot yet say microplastics are the direct cause of these health problems. Still, given the mounting evidence, many health professionals, including Dr. Kahn, advise caution.
The Gum Experiment: How the Study Was Conducted
To explore whether chewing gum could be a hidden source of microplastics, researchers at UCLA studied 10 different brands of gum—five labeled as “natural” and five synthetic. Typically, chewing gum consists of a rubbery base combined with sweeteners, flavorings, and other additives. Synthetic gums often incorporate petroleum-derived plastics, while natural gums use plant-based polymers, sometimes referred to as bioplastics.
The researchers initially hypothesized that synthetic gums would produce higher amounts of microplastics. However, the results were more complex.
In the first phase of the experiment, a volunteer chewed seven samples from each brand. Each piece was chewed for four minutes, with saliva samples collected every 30 seconds. After chewing, a mouth rinse was performed, and all the fluids were analyzed collectively. A second phase of the study had the same volunteer chew gum for 20 minutes, with saliva collected periodically to observe how the rate of microplastic release changed over time.
Key Findings: How Much Plastic Are We Chewing?
The study yielded some surprising results:
- On average, one gram of gum released about 100 microplastic particles. With typical gum pieces weighing between 2 and 6 grams, a single piece could easily shed hundreds of microplastics.
- Some gum types were particularly problematic, releasing as many as 637 microplastics per gram.
- Most microplastics were released in the first two minutes of chewing, suggesting that the mechanical act of chewing, rather than chemical breakdown in saliva, caused the gum to shed plastic fragments.
- Contrary to expectations, natural and synthetic gums released similar quantities of microplastics.
Lead author Lisa Lowe, a PhD student who began the project as an undergraduate intern at UCLA, noted that chewing roughly 160 to 180 sticks of gum annually—the typical consumption rate for some people—could result in the ingestion of approximately 30,000 microplastic particles each year.
Challenges in Measuring Microplastics
It’s important to note that the research team’s findings may actually underestimate the extent of microplastic exposure from chewing gum. The analytical instruments used could only detect particles larger than 20 micrometers, meaning that smaller nano-plastics, which might also be released during chewing, went undetected.
“This is hard to compare, because our study was limited by our analysis instruments,” explained Lowe. Comparisons with other sources of microplastic exposure, such as drinking from plastic water bottles or using plastic food containers, remain difficult without broader data capturing all particle sizes.
Should We Stop Chewing Gum?
Despite the concerning findings, researchers are not suggesting that people should immediately abandon their gum-chewing habits. “I don’t think it is very critical that we don’t chew gum. There are so many places we are exposed to microplastics, and we can’t avoid them all. But I think it is important to be aware of this issue,” said Lowe.
For those looking to reduce their exposure without giving up gum entirely, Lowe recommends chewing one piece for a longer period instead of frequently switching to a new one. Since most microplastics are shed during the first two minutes of chewing, extending the use of a single piece could help minimize total exposure.
Lingering Questions and Next Steps
Because the study has not yet been published, there are still unanswered questions about the specifics of microplastic release. Dr. Kahn points out a key unknown: “If natural and synthetic gum both release microplastics, what is the source? The gum itself or the packaging?”
Additionally, more detailed analysis could help determine whether certain types of gum, such as bubble gum or sugar-free varieties, are more prone to releasing microplastics than others. Such data could eventually guide consumers toward safer choices.
Dr. Kahn also leans toward a more cautious approach in the meantime. “It can’t hurt to be cautious,” she said. “If gum chewing is a source of microplastics, then it probably is not a great thing to do if you can avoid it, right?”
As scientific understanding of microplastics evolves, everyday behaviors such as chewing gum may warrant a second look—not necessarily out of alarm, but out of growing awareness of how pervasive plastic exposure has become.