Welcome to brain Stuff from how stuff Works. Hey, brain Stuff, Lauren vocal bomb here. Even if you're not a tobacco user, you're probably familiar with the cigarettes from their aggressive marketing campaigns and popularity with former smokers. They're the electronic battery powered devices that heat a fluid a k A. Liquid or vape juice to create an aerosol that's inhaled in place of the smoke that conventional cigarettes produced by burning
tobacco leaves. These fluids can contain any number of compounds to create the puffs of aerosol, their flavors, and their effects, including nicotine, the active ingredient in tobacco. E cigarettes are rising in popularity, with ten point eight million adult users in the US as of Part of the attraction maybe that they're perceived as being less hazards to the health than conventional smoking, since users don't receive the cancer causing
tar found in conventional cigarettes. Add to that the allure of the sweet tasting flavorings available for addition to the E liquid, and people such as US Food and Drug Administration Commissioner Dr Scott Gottlieb worry it may be all too appealing to youthful users, but that pleasant taste may
have a downside, researchers say. In a study published in October eighteen in the journal Nicotine and Tobacco Research, scientists from Duke and Yale Universities found that chemical flavorings for vanilla, cherry, citrus, and cinnamon interacted with solvents such as propylene glycol and glycerol in the E liquid, forming new compounds called acetols, which can trigger irritation and inflammation when inhaled. According to the Duke Medicine press release, the interaction occurs even before
the liquid is heated. We spoke with Hannah A. Wreath Repel, a postdoctoral associate at the Yale Tobacco Center of Regulatory Science and a co author of the study. He said, we simply don't know what long term effects these compounds and many other compounds in E cigrette liquid have on the airways. Many of the additives to E liquids have g R A S status, which means generally regarded as safe, but that's based on in jest gin and on dermal
or skin exposure. There isn't much knowledge about what these compounds might do in the airways and lungs, and that's true for all vapors, young and old earth. Repel added that scientists already know that further reactions take place during the heating step of vaping. All of this means that the initial list of ingredients for a liquid quote is likely different from the final e liquid composition, which in turn is different from what the user is exposed to
in the generated aerosol. How that might affect vapors bodies isn't yet clear, but the researchers say that the irritant compounds will persist in the body for some time after a user vapes. Over time, that mild irritation could trigger the immune system and create an inflammatory response in your body, which isn't a good thing for anyone, but especially for users with conditions like asthma and a breath. Repel notes
that the researchers have other concerns as well. He said, if this reaction can take place that creates a more irritating compound or possibly more toxic, what other reactions can take place that might cause increased risk for users? We
simply don't know. I would add that long term effects of vaping on the airways and the whole body are generally unknown given how young these devices are, independent of the final composition of the liquid, but the fact that these more irritating compounds form is certainly not reassuring in that regard. We also spoke via email with Robert Strongen, a professor of organic chemistry at Portland State University who
was not connected with the Duke Yale study. He said that just as users aren't aware of these new chemicals being created an e liquid, scientists similarly don't know much about the effect of those chemicals on the body. Quote, we know very little or nothing about the flavoring additives or even much about the solvents as far as their
inhalation toxicity, especially as chronically used in e cigarettes. A chemical safer ingestion are not necessarily safe for inhalation inhaled organic solvents and flavorings bypass processing by these stomach and liver lung tissue is different. Just because we can eat flavor molecules doesn't mean at all that it's okay to
inhale them. Earth Repel says that more research is needed on the chemical changes in e liquids and what health effects they may have, which will be a challenge seeing as how, there are an estimated seven thousand flavors or more on the market right now, and that market is growing. Today's episode was written by Patrick J. Kaiger and produced by Tyler Playing. For more on this and lots of other health topics, visit our home planet, how stuff Works dot com.