New research adds to growing evidence on the harmful health effects of e-cigarettes: Cinnamon, vanilla and butter flavors are among the most toxic.
Sugar and spices are good to eat, but not so good to inhale or vape. Exposure to the chemicals and flavoring liquids in e-cigarettes can cause significant inflammation of monocytes, a type of white blood cell, and many flavoring compounds are also toxic, the worst being those in cinnamon, vanilla, and butter.
This is the conclusion of a new study published in the open access journal Frontiers in Physiology, which has also found that mixing e-cigarette flavors has a much worse effect than exposure to just one. The study adds to growing evidence on the harmful health effects of e-cigarettes.
The consumption of electronic cigarettes has skyrocketed in the last decade, while that of traditional cigarettes has decreased. In the United States alone there are more than 500 brands of electronic cigarettes with almost 8,000 unique flavors available to consumers.
Vaping exposes the lungs to flavoring chemicals when e-cigarette liquids are heated and inhaled. Because flavorings are considered harmless, e-cigarettes are often seen – and advertised – as a healthier alternative to traditional cigarettes. However, the health effects of inhaling these chemicals are not well understood.
This new study, led by researchers at the University of Rochester Medical Center (United States), wanted to test the hypothesis that vaporizing these flavored liquids without nicotine is safer than smoking conventional cigarettes.
Previous studies have shown that flavors used in e-cigarettes trigger inflammatory and oxidative stress responses in lung cells. E-cigarette users also show higher levels of oxidative stress markers in their blood than non-smokers. The new study expands on this study to evaluate the effects of commonly used flavoring chemicals, as well as nicotine-free e-liquids, directly on immune cells, namely a type of white blood cells called monocytes.
Cinnamon, vanilla and butter flavoring chemicals were the most toxic
Exposure to flavoring chemicals from e-cigarettes and e-liquids caused increased production of two well-established biomarkers of inflammation and oxidative stress-mediated tissue damage. Additionally, many of the flavoring chemicals caused significant cell death, with some flavors being more toxic than others.
Dr. Thivanka Muthumalage, first author of the study, says that while the flavoring compounds tested may be safe for ingestion, these results show that they are not safe for inhalation. “The flavoring chemicals cinnamon, vanilla, and butter were the most toxic, but our research showed that mixing e-liquid flavors caused by far the most toxicity to white blood cells.”
Lead author Dr. Irfan Rahman says he hopes these new data will provide a better understanding of the harmful effects of non-nicotine flavored e-liquids.
“They are currently unregulated, and enticing flavor names like caramel, cake, cinnamon roll, and mystery mix appeal to young people,” he says. “Our scientific findings demonstrate that liquid flavors can, and should, be regulated and that bottles should have a descriptive list of all ingredients. “We urge regulatory agencies to act to protect public health.”
This study directly exposed monocytic blood cells to vaping liquids. The authors plan to conduct further research to simulate vaping in vivo, exposing cells to aerosols of vaping liquids in an air-liquid interface system. They also call for more long-term studies in humans to evaluate the harmful effects of e-cigarettes.