Popular flavored vape liquids like cinnamon may be toxic to the heart

A preclinical trial involving mice has found indications that the flavorings used in electronic cigarette liquids may be cardiotoxic. The researchers found popular flavors had a noticeable impact on heart cells that may lead to heart rhythm disorders, including vanilla custard, cinnamon, and the various fruit flavors.

Electronic cigarettes — more commonly called 'vapes' — are small devices that use a heating element to vaporize a liquid solution, one typically featuring nicotine, flavorings, and vegetable glycerin or propylene glycol.

These flavorings come in a huge variety, including sweet ones designed to taste like desserts, fruit blends, mints, and similar things. Critics have cited these flavors as a draw for young users, including ones who never smoked cigarettes, while proponents push back against calls for limitations on flavorings.

Research on vaping is growing steadily, but much remains unknown about this habit, including its potential long-term consequences. A new study from the University of South Florida explored the potential impact of inhaling vaporized flavorings used in these liquids. The flavoring molecules enter the bloodstream and make their way to the heart, where they were found to be toxic to HL-1 cells, at least in mice.

Using heart cells derived from human stem cells, the study also found evidence that these flavored liquids may have a cardiotoxic effect beyond that of nicotine alone. Young mice exposed to vaping five days a week for 10 weeks were found to experience interference with normal heart rate variability.

Of note, the mice that inhaled vapor were more likely than control mice to experience ventricular tachycardia, an abnormal heartbeat that can be dangerous. However, the researchers note that this study is preclinical in nature and that more research will be necessary to find out what kind of effects these flavorings may have on humans, particularly in the long term.