What do we know about microplastics and the danger they pose to us?
"Our goal is not to alarm anyone," said Sanjay Mohanty, a professor at the University of California, in a statement released to the media. "Scientists still cannot say with 100% certainty whether microplastics are dangerous to us or not, as not many studies have been conducted on humans regarding this matter."
According to previous studies, it is estimated that an average person consumes between 39,000 and 52,000 microplastic particles each year. It’s everywhere, and we are exposed to it through plastic drink and food packaging, cutting boards, sponges, and the manufacturing processes of many items we consume. Gum is simply a specific product that hasn’t been extensively studied in this context until now.
"My lab has mainly researched the impact of microplastics on soil and water. We’ve learned that there are various ways a person can be exposed to microplastics – ingestion or inhalation," said Mohanty. "Most studies related to microplastic exposure through food digestion focus on contamination from plastic packaging (plastic bottles, plastic tea bags, etc.), but gum is a food item that is itself made of plastic. And yet, most people don’t know this. We wanted to measure the amount of microplastics in gum, and it’s important to assess the exposure level and the potential negative effects it may have."
How was the study conducted?
Gum is made of flavorings, sweeteners, a chewy base, and other ingredients. In "natural" gums, the chewy base is a plant-based polymer, such as tree resin, which is what makes it "chewable." A synthetic chewy base, like a petroleum-based polymer, is used to create synthetic gums.
The researchers tested 5 types of synthetic gums and 5 types of natural gums from different manufacturers. Each participant in the study chewed 7 different pieces of gum from these types for 4 minutes, and saliva samples were taken every 30 seconds. Afterward, they rinsed their mouth with clean water, another saliva sample was taken, and all of these were combined into a single sample. The researchers also conducted a separate test in which each participant chewed gum for a longer period, with saliva samples taken every 20 minutes.
The researchers measured the amount of microplastics found in the saliva samples, and although they initially hypothesized that synthetic gums would contain more microplastics, they were surprised to find that natural gums had an equal amount. "We weren’t surprised to find microplastics in gum, but we were surprised to discover that there was an equal amount in both synthetic and natural gums," said Mohanty.
How much microplastic is in gum?
According to the study, it was found that, on average, there are about 100 microplastic particles per gram of gum. Some types of gum had more – up to 600 microplastic particles per gram. It should be noted that each piece of gum weighs around 2-6 grams. The researchers also discovered that both types of gum contained the same types of polymers, with the highest amount being polyolefin – a plastic that includes various types like polyethylene and polypropylene.
Tracey Woodruff, a professor of obstetrics and gynecology at the University of California who has studied the health effects of microplastics and was not involved in the current study, notes that the fact that gum contains microplastics isn’t all that surprising. "Nothing surprises me about this topic anymore, but it’s sad that something we put in our mouths for a long time releases microplastics. We already know we’re exposed to a high amount of microplastics because it can be found in every part of our body, but the problem is that the gum we chew adds to the list of microplastics we’re already exposed to."
What is the health impact of microplastics?
This topic is still under research. In a 2024 review of studies researchers showed that there is concern that microplastics may harm the respiratory, digestive, and reproductive systems, and they might also be linked to colon and lung cancer. Dr. Dana Hunnes, a clinical dietitian at the University of California who was not involved in the study, explains that although we know microplastics are common in our bodies today, these results are still concerning.
"Honestly, I never thought gum could be a source of microplastics! Yes, I’m very surprised by this study, and not in a good way. When chewing gum, most people tend to swallow their saliva, and if it releases microplastics into the saliva, that means we’re swallowing it, and that’s not good."
Should we stop chewing gum?
Dr. Hunnes notes that it might be worth reducing the amount of gum we chew or stopping altogether. "This study shows that both natural and synthetic gums contain the same amount of microplastics, so in this case, it doesn’t seem to matter which gum you chew. It might be better to stop chewing gum or at least reduce the frequency – especially among children, whose brains may be more sensitive to damage from chemical exposure."
Woodruff says it’s a personal choice, but she herself prefers to avoid gum. "The more you chew, the more microplastics you’re exposed to. We’re essentially adding more microplastics to what we’re already exposed to daily, so I personally prefer not to chew gum anymore. If people want to reduce their exposure to microplastics, which we already know are linked to certain health issues, it’s better to avoid chewing gum."
