• Posted March 26, 2025

Gum May Be a Hidden Source of Microplastics

That stick of gum you’re chewing? It might be minty fresh, but it could also come with a little something extra: tiny bits of plastic.

A new study finds that one piece of gum can release hundreds -- possibly thousands -- of microplastics into your saliva. 

And researchers warn it may be a hidden source of plastic exposure that many people overlook.

The small pilot study, now under peer review, was presented Tuesday at a meeting of the American Chemical Society in San Diego. Research presented at meetings should be considered preliminary.

“Our goal is not to alarm anybody,” senior study author Sanjay Mohanty, associate professor at the Samueli School of Engineering at the University of California, Los Angeles, told CNN. “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.”

Microplastics are tiny bits of plastic smaller than five millimeters. 

They can enter the body through food or air and have been found in the lungs, placenta, brain and even in testicles.

Many foods are contaminated during packaging and processing, but gum stands out for one major reason: Its base often contains actual plastic.

“Chewing gum is one of the foods we chose because it is the only food where plastic polymer is used as an ingredient,” Mohanty told CNN in an email. “Other foods are contaminated with microplastics because of how they are processed and packaged.”

The study is believed to be the first to examine or compare “microplastics in chewing gums available commercially,” Mohanty added.

The researchers tested 10 popular gums sold in the U.S. Half were synthetic, and half were made with natural ingredients. One person chewed each gum for roughly four minutes while saliva was collected. It was then analyzed for microplastic particles.

The upshot: Chewing one gram of gum released an average of 100 microplastics. One unidentified gum released up to 637 particles per gram.

Since gum sticks often weigh more than that, the true exposure could be higher. 

What's more, 94% of the microplastics appeared in the first eight minutes of chewing.

Surprisingly, natural and synthetic ones performed similarly. On average, synthetic gums had 104 particles per gram, while natural ones had 96.

Both types mainly released four types of plastic: polyolefins, polyterephthalates, polyacrylamides and polystyrenes.

These are the same materials found in many plastic consumer goods and packaging, Tasha Stoiber, senior scientist at the Environmental Working Group, a nonprofit environmental health organization, told CNN in an email.

David Jones, a teaching fellow in the School of the Environment and Life Sciences at the University of Portsmouth in England, reviewed the findings.

The release of microplastics was not unexpected, he said.

“If we subject any type of plastic to stress, be it heat, friction, sunlight, seawater, or in this case vigorous mastication, we know that microplastics will be released from the plastic material,” Jones said. “We inhale, ingest and drink something like 250,000 plastic particles a year without trying. … But at least we now have some robust data and it is a good starting point for further research.”

The National Confectioners Association, which represents gum makers, said "gum is safe to enjoy as it has been for more than 100 years. Food safety is the number one priority for U.S. confectionery companies."

More information

The U.S. Food and Drug Administration has more on microplastics and nanoplastics in foods.

SOURCE: CNN, March 25, 2025