Chewing gum is one of those everyday habits most people rarely think about.
You might chew a piece after lunch, during a long study session, or simply because you enjoy the flavor. It seems harmless: a small piece of gum goes into your mouth, loses its flavor and eventually ends up in the trash.
But new research has raised an unexpected question: Could chewing gum itself be a source of microplastic exposure?
A pilot study from researchers at the University of California, Los Angeles, presented at the American Chemical Society’s Spring 2025 meeting found that both synthetic and natural chewing gums released microplastic particles into saliva during chewing.
The finding is intriguing, but it needs to be put into perspective.
Researchers have not established that chewing gum is harmful to human health because of these particles. There have been no clinical trials showing that people who chew gum develop a particular disease or health problem as a result of microplastic exposure from gum.
For now, the study is best understood as an early piece of evidence about a previously overlooked source of exposure.
A Surprisingly Simple Experiment
The UCLA team, led by civil and environmental engineering professor Sanjay Mohanty and graduate researcher Lisa Lowe, tested 10 commercially available chewing gums.
Five were classified as synthetic gums, while five were marketed as natural gums using plant-based polymers such as chicle or other tree-derived materials. Researchers examined saliva produced while one participant chewed the gum and analyzed the released particles.
The results were striking.
Researchers estimated that gum released approximately 100 microplastic particles per gram on average, although some products released considerably more. Because individual pieces can weigh several grams, some pieces could release thousands of particles during chewing.
The researchers also found that most of the particles were released early in the chewing process.
According to the study, about 94% of the particles collected during the experiments had been released within the first eight minutes.
That suggests the mechanical action of chewing—not digestion or saliva breaking down the gum—was an important factor.
Natural Gum Wasn’t Necessarily Free of Microplastics
Perhaps the most surprising finding was that products marketed as natural did not clearly escape the problem.
The researchers expected synthetic gums, which use polymer-based gum bases, to release more microplastics.
Instead, natural and synthetic products produced similar levels of particle release in the experiment. Researchers said they are continuing to investigate where the particles detected in natural gums originate.
That does not mean every product labeled “natural” contains the same ingredients or that all natural gums are made from petroleum-based plastics.
It does mean that consumers should be cautious about assuming that a “natural” label automatically means zero microplastic exposure.
What Exactly Is Gum Made From?
Traditional chewing gum has historically been made using natural plant materials such as chicle.
Modern commercial gum can instead use synthetic polymers in its gum base to provide elasticity, chewiness and durability.
The ingredient list may simply identify this component as “gum base.”
The precise composition varies between products.
The UCLA researchers detected polyolefin-type plastics, including materials associated with synthetic polymers, in their analysis. However, the study does not justify claiming that every chewing gum contains specific plastics such as polyethylene or polystyrene.
That distinction matters because food products vary considerably in their formulation.
What Happens When We Swallow Microplastics?
This is where the science becomes much less certain.
Microplastics are tiny plastic particles that can enter the environment and human food and water supplies through numerous pathways.
Scientists are actively investigating whether exposure has consequences for human health. Laboratory studies involving cells and animals have raised concerns about possible biological effects, but these findings cannot automatically be translated into disease risk for people.
The UCLA researchers themselves emphasized that the health effects of microplastics from chewing gum remain unknown and that human clinical trials have not established harm.
That is an important distinction.
Finding particles in saliva tells researchers that exposure is possible.
It does not tell us that the exposure causes cancer, digestive disease, inflammation or another specific illness.
Those questions require substantially more research.
Why the Finding Still Matters
Even without proof of harm, the study is important because it identifies another potential pathway for human exposure.
People encounter plastic particles from numerous sources, including food packaging, drinking water and the environment.
Chewing gum is unusual because the material being chewed can itself contain polymeric ingredients.
That makes it worth studying.
The researchers also point out that their laboratory methods detected particles at or above approximately 20 micrometers. Smaller particles, including nanoplastics, may not have been captured by the methods used in the pilot study.
In other words, scientists are still learning how much exposure occurs and what types of particles may be involved.
Should You Stop Chewing Gum?
There is currently no scientific reason to panic over an occasional piece of chewing gum.
The UCLA findings do not establish that chewing gum is dangerous, and the researchers specifically cautioned against alarming consumers.
If you enjoy gum, the new research is better viewed as a reason to stay informed rather than a reason to assume the worst.
The study did suggest that most of the measured particle release happened early during chewing. Researchers therefore suggested that, for people concerned about exposure, chewing one piece for longer rather than repeatedly starting new pieces could potentially reduce the number of newly released particles over the same period.
That suggestion, however, is based on particle-release measurements—not on a demonstrated health benefit.
The Bigger Question About Microplastics
The real story may be larger than chewing gum.
Microplastics are increasingly being detected in everyday environments, food and biological samples, and researchers around the world are trying to determine what prolonged exposure means for human health.
The scientific challenge is separating exposure from harm.
We now know that people encounter microplastics.
What remains uncertain is how much exposure is biologically important, which particle sizes and chemical compositions matter most, how the body handles them and whether long-term exposure contributes to specific diseases.
Those answers will require carefully designed human research.
For now, the message from the chewing-gum study is surprisingly simple: something as ordinary as chewing gum can release microplastic particles into saliva, but scientists are still determining what that exposure means for our health.
That makes the discovery worth paying attention to—but not worth turning into a new health scare.
Photo by Vika Glitter: https://www.pexels.com/photo/model-in-sunglasses-blowing-bubble-gum-balloon-17091666/