A new study from Duke Health has revealed that electronic cigarettes flavored with mint and menthol, and smokeless tobacco products contain a potential cancer-causing food additive in alarmingly high levels.

E-cigarettes and smokeless tobacco products are said to be safer alternatives to regular cigarettes. However, these products have been found to contain pulegone, which is a food additive banned by the Food and Drug Agency last year due to its cancer-causing properties.

Despite this, the FDA does not regulate pulegone levels in e-cigarettes and smokeless tobacco, which are promoted as safer alternatives to regular cigarettes.

"Our findings suggest that the FDA should implement measures to mitigate pulegone-related health risks before suggesting mint- and menthol-flavored e-cigarettes and smokeless tobacco products as alternatives for people who use combustible tobacco products," said Sven-Eric Jordt, Ph.D., a professor of the Department of Anesthesiology at Duke and lead author of the study published in JAMA Internal Medicine.

Carcinogens cause cancer by producing mutations in the genetic material, or DNA, of a cell. These mutations result in uncontrolled cell division, leading to tumour formation. Pixabay

Jordt and research partner Sairam V. Jabba became interested in the topic after the U.S. Centers for Disease Control and Prevention (CDC) published studies showing that mint- and menthol-flavored e-cigarette liquids and smokeless tobacco products marketed in the U.S. contain substantial amounts of pulegone.

Of the several top brands of regular menthol cigarettes, three e-cigarette brands, and one smokeless tobacco brand they examined, the e-cigarettes and smokeless tobacco products had levels pulegone exceeding the thresholds of concern. These threshold values were obtained from the FDA’s exposure risk data and are levels at which exposure-related tumors start appearing, as reported in animal studies.

"Our analysis suggests that users of mint- and menthol-flavored e-cigarettes and smokeless tobacco are exposed to pulegone levels higher than the FDA considers acceptable for intake in food, and higher than in smokers of combustible menthol cigarettes," Jordt said.

"The tobacco industry has long known about the dangers of pulegone and has continuously tried to minimize its levels in menthol cigarette flavorings, so the levels are much lower in menthol cigarettes than in electronic cigarettes," Jordt said. E-cigarette manufacturers may be less familiar with the dangers and use cheaper ingredients to lower costs.

One constraint this study poses is that the exposure risk calculations are based on oral exposure in animal studies. These risks may apply to oral exposure through smokeless tobacco but may differ from inhalation exposure through e-cigarette vapor. There is no toxicity data available on exposure via inhalation. This is concerning because toxicologists consider the lung to be more sensitive to toxic chemicals than the digestive tract.