Vaping’s potential harms may extend beyond the lungs, a new study published on Wednesday in Science Advances suggests. Looking at the mouths of young healthy vapers, the study found evidence of drastic changes to the oral microbiome—changes that could raise their future risk of gum disease.
Smoking is well known to seriously damage our mouth’s health, causing teeth staining, gum disease, and sometimes cancer. Researchers have theorized that smoking does this is by affecting the microbiome, the usually helpful neighborhoods of bacteria and other microbes that live in and on the human body. It turns out that vaping may mess with the mouth’s bacteria too, though not necessarily in the same way as smoking does.
Lead author Purnima Kumar, an oral surgeon and professor of dentistry at Ohio State University, and her team were originally interested in studying how our mouth’s microbiome bounces back when someone quits smoking. While conducting that study, Kumar came across patients who asked for advice on how to quit, and she initially recommended vaping as a way to ease off cigarette use. But the more she thought about it, the more she realized that we still have little idea of how vaping could influence people’s oral health.
“I was telling people something that was absolutely not evidence based,” Kumar told Gizmodo. “And it went against everything I believed in, so we started studying it.”
Kumar’s team took samples of plaque—the sticky film of bacteria that coats our teeth—from more than 120 young, healthy volunteers. These volunteers included people who had vaped for at least 4 months, smokers, people who had stopped smoking and were now vaping, people smoking and vaping at the same time, and a control group that did neither. Then they sequenced the genetic material found in their plaque.
“We’re using the microbiome almost like a canary in the coal mine. It responds very quickly to environmental changes in a measurable way long before the human body responds to it. So it almost foretells the future for us,” Kumar said. “What we saw is that e-cigarettes create an incredible amount of stress in the microbiome. And these bacteria respond to the stress by creating a very mucousy, slimy layer.”
These slimy changes to the microbiome, according to Kumar, likely antagonize the immune system, making the mouth more likely to become chronically inflamed. Over time, that inflammation could lead to serious gum disease. That could then harm the body elsewhere, since research continues to link gum disease to a higher risk of other ailments, like heart disease.
“These people have no evidence of gum disease,” Kumar said. “They would get a clean bill of health in my office. But when you compare their microbiome to people who already have established gum disease, it’s so similar. So at a molecular level, these people are already starting to shift away from a healthy mouth. This would take years to manifest, but most oral diseases are chronic diseases. And we don’t even know what kinds of new diseases we might get from these kinds of microbial changes.”
The changes the team found seem unique to vaping, and they might even be more potent than what we see with smoking. In both former smokers who switched to vaping as well as dual users, their microbiomes more resembled those from people who only vaped. In later experiments using fake mouths, they also found evidence these changes happened even from vaping aerosol without nicotine. That suggests it’s the ingredients glycerol and glycol, used to create vaping clouds, that are more to blame.
Of course, there’s still lots more research that has to be done to confirm their results, as well as to better understand how vaping could affect our mouth health. For one, they largely only studied people using older-generation modifiable vaping devices, as opposed to the simpler pods popularized by Juul. Kumar’s team is now studying these newer devices.
Kumar doesn’t discount the potential of e-cigarettes as a way to help people quit smoking, so long as they’re used temporarily. But for people who permanently switch to vaping from smoking or continue to use both, she fears that they’re simply trading one known harm for one that we still know very little about.
“In my ideal world, someone would use an e-cigarette to quit smoking and then remove the nicotine from it and then quit e-cigarettes in three months. But if you’re simply using e-cigarettes to quit smoking, you’re not going through cessation,” she said. “We are dealing with an entirely unknown commodity and the narrative of its safety might have been overstated. We really need a lot more understanding of these products before we make these grandiose statements about their safety.”