A New Hazard in Mint- and Menthol-Flavored E-Cigarettes: Pulegone!

Smoking is a leading preventable cause of death, and almost 90% start smoking before age 18. In 95 percent, the starting age is 21 or younger. Only 1 percent smoke their first cigarette after age 26.

FDA(US Food and Drug Administration) banned menthol- and mint-flavored cigarettes in early 2019, primarily to remove flavorings that facilitate youth initiation and make smoking seem harmless.

In 2019, in 2 leading scientific publications, NEJM and JAMA, 2 articles drew attention to risks of menthol- and mint-flavored conventional and electronic cigarettes. Published on 14 March, the NEJM article concerned the FDA menthol cigarette ban. On 16 September, JAMApublished an article announcing that menthol and mint flavors used in e-cigarettes Group 2B carcinogen (cancer-causing) compounds had been detected. This article primarily uses data from the second paper.

As health concerns about e-cigarettes increase, researchers continue investigating e-cigarette-associated lung diseases and harmful flavoring components in greater depth.

Duke University School of Medicine researchers found that menthol e-cigarette users in particular were exposed to 1000 times higher pulegone levels. Pulegone is an oil derived from mint plants.

According to the International Agency for Research on Cancer (IARC), pulegone is a Group 2B carcinogen: sufficient animal evidence indicates carcinogenicity, but human study data are scarce.

This component had been used as a food additive, but following complaints in 2018 the FDA banned synthetic pulegone in food additives. The tobacco industry knew in the 70s that pulegone was undesirable and switched to synthetic flavors. Today, CDC (US Centers for Disease Control and Prevention) research has detected substantial pulegone in mint- and menthol-flavored e-cigarette liquids and smokeless tobacco sold in the USA.

Margin of Exposure (MOE)

To calculate acceptable food carcinogen levels, the FDA takes the highest amount animals can consume without tumors and divides it by estimated daily consumption. This margin of exposure (MOE) must exceed 10.000 for food to be considered safe. Low MOEs are concerning; the lower the number, the less safe the food.

Researchers tested 6 pulegone-containing e-cigarette liquids and found MOE levels below 10,000 in one in particular.

In conclusion, this study again demonstrates that a substance consumed as food may not have the same effects when inhaled. Menthol and mint ingredients banned in cigarettes require stricter attention both to prevent youth nicotine habits and because they contain carcinogenic agents.