Many of us don’t think twice about casually popping a stick of gum in our mouth. But chew on this: When you do, you’re also chomping on, and possibly ingesting, hundreds, if not thousands, of microplastic particles, according to researchers at the UCLA Samueli School of Engineering.
With the growing awareness that these tiny, micrometer-wide particles are present in scores of everyday items — including plastic bottles, cooking utensils and food packaging materials — and end up in what we eat, UCLA’s Sanjay Mohanty decided to test the very popular but not yet widely studied chewing treat.
Mohanty, an associate professor of civil and environmental engineering, and engineering graduate student Lisa Lowe presented the findings of their pilot study at the spring meeting of the American Chemical Society in San Diego.
How many microplastics are in chewing gum?
The pair tested 10 brands of commercially available chewing gum, including five synthetic gums, which rely on petroleum-based polymers for their chewiness, and five natural gums, which use plant-based polymers like chicle or other tree sap.
In the lab, a subject chewed seven pieces of each brand for four minutes, with Mohanty and Lowe collecting saliva samples every 30 seconds. In a second experiment, they collected samples repeatedly over 20 minutes to measure the rate at which microplastics were released from each piece of gum.
To their surprise, the researchers said, the natural and synthetic gum types released similar levels of microplastics.
So how high was the level?
A typical piece of gum weighs between 2 and 6 grams. Mohanty and Lowe found that, on average, 100 microplastic particles were released for each gram of gum chewed — though some gum types emitted up to 600 particles per gram. So, a person happily gnawing away on a large piece could unleash more than 3,000 microplastic particles, according to the UCLA team.
A person chewing 160 to 180 pieces of gum a year, they said, could potentially be ingesting 30,000 microplastics. And while the effect of ingested microplastics on human health still isn’t clear, animal studies and studies with human cells have shown that they may cause harm.
“Our goal is not to alarm anybody,” said Mohanty, principal investigator of the study. “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.”
If the news about microplastics in gum feels alarming, the UCLA researchers found that 94% of the particles were released during the first eight minutes of chewing. So, if you want fewer microplastics, stick to chewing a single piece longer, Lowe said.
