PALO ALTO, Calif. (KTVU) - A Stanford medical team has found the flavors in e-cigarettes are by themselves, damaging to the heart and arteries.
As many Bay Area cities restrict vape sales amid concern about health effects, the new research suggests nicotine isn't the only thing to worry about.
"I always thought, if it's nicotine free, it's fine," Sarah Herzog,18, told KTVU, "and the flavor makes it good, I think people do it specifically for the flavor."
Vaping is rampant among teenagers; Herzog and her friends are high school seniors who have seen the popularity of the devices explode.
"I have friends that go crazy, they sweat, and can't breathe if they haven't hit their Juul," said Destiny Hale, also 18.
The new research comes from Stanford University's School of Medicine.
It suggests that flavored e-liquids may increase the risk of cardiovascular disease.
"I got into this research because my wife asked me to look into it," cardiologist Dr. Joseph Wu told KTVU.
Wu has two teenagerchildren, so the rise in e-cigarettes was more than an academic interest.
In the lab, his team- using stem cell technology- grew the cells that line blood vessels.
Then they were exposed to the liquids, or to the blood collected from e-cig users shortly after vaping.
"We found increased stress to the cells, increased inflammation to the cells and also increased cell death," explained Dr. Wu.
The results were surprising, he says, because the harm occurred whether or not nicotine was iin the mix.
Flavorings alone were enough to cause vascular damage.
Two flavors, menthol and cinnamon, were particularly toxic.
"So this is a warning shot to the public and to the teenagers," Wu said, "that these e-cigarettes are not completely safe, and if possible the teenagers should think about quitting."
The study examined the effects of six flavors; there are more than 4,000 on the market.
The research was met with ready sceptism from those who sell vaping products.
"Why aren't cities banning sugar, refined flour, and things that cause heart disease," asked Ted Turina, owner of VIP Vape, an established smoke shop in San Rafael.
Turina and his staff say medical research is far from unanimous, and they don't expect customers to quit because many vaping preferable to inhaling the carcinogens of tobacco products.
"We're comparing it to people who used to smoke cigarettes, and they are a lot healthier, it is a lot healthier," said Rebecca Williams, who supervises vape merchandise at VIP.
"If e-cig is really a problem, why aren't we having people tell us they're having health problems from it, because they tell us the opposite," said Turina.
But Wu, and others in the medical community, are concerned about the attraction fruity flavors have for young people.
"We're talking about a whole generation of young kids who will be addicted to vaping," said Wu, "and my hunch is they will end up with cardiovascular disease as well."
Young people themselves may -or may not- heed the new research.
"I don't think it will stop anything because people know that nicotine is bad, and they're still doing it," said Hale. She and her friends say they hit a vape very rarely.
"I used to vape because it was the cool thing to do, and I figured it wasn't like cigarettes," said Herzog, "plus look around, models are doing it, celebrities are doing it."
The Food and Drug Administration estimates that more than 3.5 million middle and high school students used e-cigarettes in 2018, although sales to minors are prohibited.