That stick of chewing gum providing a moment of freshness or stress relief might also be delivering an unintended dose of tiny plastic particles directly into your mouth, according to new research. Scientists at the University of California, Los Angeles (UCLA) have found that chewing a single piece of gum can release hundreds, potentially even thousands, of microplastic pieces into saliva, likely destined to be swallowed. This finding adds another everyday source to the growing list of ways humans are exposed to ubiquitous microplastic pollution, raising further questions about potential health impacts.
Ubiquitous Plastics, Uncertain Risks
Microplastics (particles smaller than 5 millimeters) and even smaller nanoplastics have permeated virtually every environment on Earth, from the deepest oceans to the air we breathe. Consequently, they're also finding their way into our bodies. Previous studies have detected these particles in various human organs, including the brain, liver, kidneys, testes, and even the placenta. Scientists estimate humans may consume tens of thousands of microplastic particles annually through food, water, and air.
While the presence of microplastics in the human body is established, the direct impact on health remains largely unknown and is an area of active scientific investigation. "Scientists don't know if microplastics are unsafe to us or not. There are no human trials," explained Professor Sanjay Mohanty, a UCLA environmental engineer and co-author of the study. Studies on animals and human cells have suggested potential harms, including inflammation and cellular damage, fueling concerns. However, Mohanty emphasized, "Our goal is not to alarm anybody... But we know we are exposed to plastics in everyday life—and that's what we wanted to examine here."
The Chewing Gum Experiment
To investigate gum as a potential source, Mohanty and his colleague Lisa Lowe, a UCLA biological engineer, analyzed ten different commercially available gum brands. Five were "natural," using plant-based polymers like chicle as their rubber base, while the other five were "synthetic," employing petroleum-based polymers.
Their methodology involved subjects chewing each gum brand for specific durations. In one set of experiments, saliva was collected incrementally over four minutes, combined, and analyzed. In another, saliva samples were taken over 20 minutes to study the rate of release. The researchers stained the collected plastic particles red for visibility and counted them under a microscope. They also used Fourier-transform infrared spectroscopy to determine the chemical composition of the released plastics. A key limitation acknowledged by the team is that their counting method only detected particles 20 micrometers or larger, meaning the actual number of released micro- and potentially nanoplastics is likely higher than reported.
Surprising Findings: Quantity and Composition
The results showed significant microplastic release. On average, chewing released about 100 microplastic particles per gram of gum. However, some individual pieces shed as many as 600 particles per gram. Given that larger gum pieces can weigh up to 6 grams, a single piece could introduce over 3,000 detectable plastic particles into the mouth. The researchers noted that a regular gum-chewing habit could significantly increase an individual's total microplastic intake compared to exposure from food and drinks alone.
Surprisingly, the team found "similar amounts of microplastics released" from both natural and synthetic gums, contradicting their initial hypothesis that synthetic bases would release more. Furthermore, both types contained the same dominant polymers: polyolefins, a common plastic group that includes polyethylene (used in plastic bags) and polypropylene (used in packaging).
The study also pinpointed when most release occurs. The mechanical action of chewing, rather than saliva's enzymes, was the primary driver, with the bulk of microplastics (up to 94%) being shed within the first two to eight minutes.
Recommendations and External Perspectives
Based on the release timing, Lowe suggests a potential harm reduction strategy: "if people want to keep chewing gum, but reduce their exposure to microplastics, they chew one piece for longer rather than having multiple pieces." The researchers also highlighted the environmental impact of discarded gum, noting the plastic released into saliva is only "a small fraction" of the plastic within the gum itself, urging proper disposal.
Professor Oliver Jones, a chemist at RMIT University in Australia not involved in the study, offered perspective, calling the reported number per piece "a very small amount indeed" and suggesting swallowed particles would "likely pass straight through" without impact due to the gut lining. He concluded, "I don't think you have to stop chewing gum just yet—although you should certainly dispose of it appropriately."
The National Confectioners Association (NCA) reinforced the safety message, telling Newsweek, "Gum is safe to enjoy...Food safety is the number one priority...and our member companies use only FDA-permitted ingredients."
The UCLA findings were presented at the American Chemical Society's spring meeting in San Diego, contributing another piece to the complex puzzle of microplastic exposure and its potential consequences, even as the debate on the level of risk continues.
Source link:https://www.newsweek.com/microplastics-chewing-gum-mouth-saliva-pollution-health-2049922
Comments