Chewing Gum Could Release Millions of Microplastics Into Saliva?

Chewing gum can release hundreds to thousands of microplastics into the saliva that may be ingested, a new study found.

• A recent study found that chewing gum releases hundreds to thousands of microplastics per gram, making it an unexpected source of contamination.
• Researchers discovered microplastics in both synthetic and natural gum varieties, raising concerns about their safety.
• Although the long-term effects of microplastic exposure remain uncertain, emerging research suggests several potential health risks.

Chewing gum can release hundreds to thousands of microplastics into the saliva that may be ingested.

Researchers presented findings at the American Chemical Society’s spring meeting in San Diego, CA, showing that, on average, chewing gum releases 100 microplastics per gram. The study has not yet undergone peer review.

“Our goal is not to alarm anybody,” Sanjay Mohanty, PhD, the project’s principal investigator and an engineering professor at the University of California, Los Angeles (UCLA), said in a press 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.”

Past research estimates that an individual consumes between 39,000 and 52,000 particles of microplastics annually.

Microplastics are widespread, and humans encounter them through drinks, foods, plastic packaging, chopping boards, sponges, product coatings, and manufacturing processes.

Researchers have largely overlooked chewing gum as a potential source of microplastic exposure.

Mohanty’s lab studies how microplastics move through water and soil, as well as their effects on soil composition. Through their work, they identified ingestion and inhalation as two primary exposure routes.

Most food-related ingestion studies focus on microplastic contamination from plastic containers, such as water bottles or tea bags. However, Mohanty emphasizes that chewing gum is unique—it contains plastic as a core ingredient, yet many people remain unaware.

Determined to measure microplastic levels in chewing gum, Mohanty’s team aims to estimate total microplastic exposure in the human body and assess its potential health risks.

Chewing Gum Consumption and Microplastic Contamination

Chewing gum is made with flavoring, sweetener, a rubber base, and other ingredients.

In chewing gums that are “natural,” a plant-based polymer, like tree sap, gives the gum chewiness. Synthetic rubber bases from a petroleum-based polymer (plastic) are used for synthetic gums.

The researchers examined five types of synthetic gum along with five types of natural gum that are commercially available.

As part of the experiment, one person chewed seven pieces of gum from each brand to account for varied chewing patterns and saliva.

Researchers instructed participants to chew gum for four minutes, collecting saliva samples every 30 seconds before rinsing their mouths with clean water. They then combined the samples into a single test sample.

In a separate experiment, researchers gathered saliva samples every 20 minutes to examine microplastic levels.

They analyzed the samples, expecting synthetic chewing gum to contain more microplastics. However, they were surprised to find that natural gum had similar amounts.

Mohanty emphasized that while they anticipated finding microplastics in chewing gum, they were shocked to discover equal levels in both synthetic and organic varieties. They had assumed organic gum would contain fewer microplastics than synthetic gum. The source of microplastics in natural gums remains unclear.

Microplastics found in synthetic and natural gums

Researchers found that chewing gum releases about 100 microplastics per gram, with some pieces emitting up to 600 microplastics per gram.. Given that a typical piece of gum weighs between 2 and 6 grams, this raises concerns about exposure levels.

Further analysis revealed that both synthetic and natural gums contained the same types of polymers, with polyolefins—plastics like polyethylene and polypropylene—being the most abundant.

Tracey Woodruff, PhD, a professor of obstetrics and gynecology at UCSF, studies the health effects of microplastics and finds the results unsurprising. Although she didn’t participate in the research, she emphasizes that plastics have become present in nearly every aspect of daily life.

“She expressed concern about microplastics in food and items kept in the mouth for long periods, highlighting potential health risks.

She emphasized that humans are already exposed to various microplastics, as they’ve been detected throughout the body. However, gum further increases that exposure, adding to existing levels of plastic consumption.

HHealth impacts of microplasticsealth impacts of microplastics

The health impacts of microplastics on humans are still the subject of ongoing research.

One 2024 review found that microplastics were suspected to harm human respiratory health, digestive health and reproductive health and were also possibly associated with colon and lung cancer.

Dana Hunnes, PhD, a senior clinical dietitian at UCLA Health, told Healthline that despite knowing that microplastics are widespread, the findings of the study are still shocking. Hunnes wasn’t involved in the study.

“I honestly never would have thought to even think about chewing gum as a source of microplastics! Yes, I am very surprised with this study, and not pleasantly so.

Is it time to reconsider chewing gum?

Experts urge individuals to reduce or stop chewing gum to minimize microplastic exposure.

Hunnes advises limiting gum consumption, especially for children, since both natural and synthetic gums contain similar amounts of microplastics. She warns that developing brains may be more vulnerable to harmful chemicals.

Woodruff chooses to avoid chewing gum entirely, emphasizing that frequent chewing increases microplastic intake and adds to existing plastic exposure. Most people swallow their saliva while using gum, so ingesting microplastics from it raises concerns about potential health risks.

For those looking to lower their exposure to microplastics, avoiding chewing gum is a practical way to reduce potential health risks.