Vaping these popular flavors may cause 'significant' health damage

A new study out of Stanford University School of Medicine warns that vaping flavored nicotine liquids, including versions that don't contain nicotine, may cause 'significant damage' to endothelial cells on the inside of blood vessels, fueling cardiovascular disease risk. The negative effects were found to vary in severity based on which flavorings were used with the liquids — and, the study warns, some of the most popular options were the most harmful.

The issue of electronic cigarette use and its potential impact on long-term health remains contentious, with some proponents reacting strongly against any notion that vaping may be risky. Despite that backlash, a growing body of evidence points toward multiple possible health risks, including things like wheezing in the short-term and possibly heart issues in the future.

A number of relatively new studies have implicated the flavorings used in many e-liquids as the potential point of concern. Though vaping plain, unflavored liquid has been found to cause temporary changes in participants' lungs, a number of flavorings used in these liquids have been linked to inflammation and other potentially serious health outcomes.

In the most recent study, Stanford researchers found that menthol and cinnamon were 'particularly harmful' compared to other popular flavors, though other flavorings were also linked to concerning endothelial cell damage. "When we exposed the cells to six different flavors of e-liquid with varying levels of nicotine, we saw significant damage," explained Stanford's Joseph Wu, MD, PhD.

The study involved exposing endothelial cells, which line the interior part of blood vessels, to both the blood of people who had vaped shortly before the samples were collected, as well as directly to e-liquids of varying nicotine strengths. The experiments involved human endothelial cells that were produced in a lab using pluripotent stem cells. This is the first study to look at the potential health effects of flavored vaping liquids using human cells derived from these stem cells.

The endothelial cells lining the interior of blood vessels have a 'critical' role in one's overall cardiovascular and heart health. Many popular flavorings may be causing significant damage to these cells, unfortunately, including the following:

- Cinnamon

- Menthol

- Sweet butterscotch

- Sweet tobacco with caramel and vanilla flavors

- Fruit

- Tobacco

Multiple flavorings were described as 'moderately toxic' to the endothelial cells with the exception of menthol and cinnamon, which were described as 'particularly' damaging. Even without nicotine in the solution, these liquid flavorings (when vaped) caused a drastic decrease in cell viability. As well, exposure to these liquids increased the levels of molecules linked with programmed cell death and boosted levels of molecules that may cause DNA damage.

The problems continue from there. Both menthol and cinnamon flavorings 'significantly disrupted' the cells in a way that may inhibit the growth of new blood vessels. Cinnamon, caramel, and vanilla flavors were found to boost the uptake of LDL and lipids, while caramel and vanilla also potentially negatively impacted new blood vessel growth.

Only some of these negative health effects were dependent on nicotine concentrations, according to the study; others, including a drop in cell viability, were present even in the absence of nicotine.