A new study by UNC School of Medicine researchers shows that e-liquids for e-cigarettes and other “vaping” products can be toxic to human cells.
E-liquids usually contain nicotine and flavorings in a base liquid of propylene glycol and vegetable glycerin. The researchers tested how e-liquids affect growth of human cells in a lab. The more the growth of cells is reduced, the more toxic the e-liquid is.
Many of the ingredients found in e-liquids like propylene glycol and vegetable glycerin are considered safe to be eaten, but the effects of these ingredients on lung cells when they are inhaled may not be safe. In this study, even cells exposed to small doses of propylene glycol and vegetable glycerin (without other ingredients like nicotine and flavorings) showed significantly reduced growth.
The researchers found that some e-liquids are more toxic than just the base ingredients (propylene glycol and vegetable glycerin) and nicotine alone. They analyzed 148 e-liquids to find what specific ingredients were in each one and tested each e-liquid’s effect on cell growth. Overall, they found that each e-liquid could have very different ingredients from the next. They also found that the more ingredients an e-liquid had, the more toxic it was.
Two e-liquid ingredients seemed to be the most toxic: vanillin, which gives e-liquids a vanilla flavor, and cinnamaldehyde, which gives them a cinnamon flavor. These flavoring ingredients are used in many e-liquids. E-liquids with more vanillin and cinnamaldehyde were more toxic to cells.
Because e-cigarettes and “vaping” products are relatively new, there has not yet been regulation on e-liquids. But the FDA is beginning to regulate e-liquid ingredients. The findings from this study will likely help the FDA as they start regulating e-liquids. The tests used to determine how toxic e-liquids are could be used to test the more than 7,700 different e-liquids that are on the market now.
E-cigarette use is becoming more and more popular, particularly among youth and young adults, and it is important to understand how using these products can affect our bodies.
The researchers have set up a database of e-liquid ingredients and toxicity data that anyone can access. The results from their tests can be found at www.eliquidinfo.org.
More information on the study can be found here.
Full text journal article can be found here.