Not Kool- Menthol and Lung Numbing w/ Prof. Sven Jordt

Over the last several years, I have gotten to know Carrie Nyssen of the American Lung Association.  She works tirelessly to advocate to our state level policy makers about the importance of clean air and tobacco control. I first met her when she took me around the Oregon State Legislature meeting lawmakers to advocate for raising the tobacco purchase age to 21 and for decreasing diesel emissions. In a podcast last year, she shared how her own father disliked a non-flavored cigarette the first time he tried one, but then he was handed a menthol cigarette by a friend in the Army, and his decades-long addiction began. 

Tobacco targeting then & now

Why is menthol in particular so good at getting people addicted to tobacco? Why has the tobacco industry been fighting to keep its effects for so long?  

 

To dive into that question, and what makes menthol in particular a deadly flavor when combined with tobacco, I talked to an expert on the effects of menthol on the lungs for this post and podcast episode. Dr. Sven Jordt PhD is a scientist who shares his own journey with cigarette addiction and empathizes with the difficulty of quitting. He is Associate Professor of Anesthesiology, Pharmacology & Cancer Biology at Duke University School of Medicine and Adjunct Associate Professor of Psychiatry at Yale School of Medicine, where he is a member of the NIDA & FDA-supported Yale Tobacco Center of Regulatory Science. He also is a member of the Tobacco Action Committee of the American Thoracic Society.

His laboratory at Duke is studying how lungs sense chemicals and how they can lead to lung inflammation and damage. His research has contributed to the discovery of menthol receptors that lead to the cooling and numbing effects of menthol, and how menthol can increase the rates of people starting to smoke. His work is cited in FDA’s proposed ruling on menthol, in publications of the WHO and in international regulatory proposals and decisions.

I often tell my patients that smoking or vaping a menthol flavor is like inhaling a cough drop with the toxin. Dr. Jordt’s research shows that is essentially what is happening. It’s not surprising that he is faculty in an anesthesiology department, the menthol is literally anesthetizing the lungs so they cannot feel the toxic effects that they would normally reject. Many people, including Carrie’s dad, share that the first time they tried a cigarette, they coughed, felt sick, and more. It is natural to feel terrible when we inhale something so bad for us. The menthol numbs the lungs and lets people inhale more and more nicotine, bypassing that toxic effect and cementing their addiction. 

 

Dr. Jordt describes in the podcast interview how tobacco industry scientists have created ways to get that numbing effect without the “mint” taste and will try to use this to make even more flavors that are numbing and addictive and to get around flavor bans. Dr. Jordt has noted they are adding this into other flavors without providing warning that this will bypass our natural response to inhaling toxins. 

There are also carcinogens in some minty flavors, such as pulegone, which Prof Jordt’s team has found in unsafe concentrations in some mint-flavored e-cigarette devices. There is also a great deal of secondary chemistry that can happen when the disclosed chemicals put into an e-cigarette sit around and mix at room temperature. Many times a variety of aldehydes and alcohols are listed as the ingredients, but these sitting around together can react and form a whole host of new chemicals such as acetals that are not disclosed. Dr. Jordt’s group has shown that these new chemicals are also present in the vapor and that they are far more irritating to the lungs than the parent chemicals that are described. 

Dr. Jordt also described the variety of ingenious ways e-cigarette manufacturers have created for kids to hide e-cigarettes at school, from e-cigs shaped like smart watches and with hidden pockets in hoodies and backpacks to the now ubiquitous mini disposable devices. 

I have sat in testimony sessions about various tobacco flavor ban bills, and several of the arguments against flavor bans often arise. Since some people are able to stop using combustible tobacco by using e-cigarettes, people will argue, especially people who sell flavored e-cigarettes, that they should therefore be widely available everywhere to help people quit smoking. This is nonsense. You don’t need to attract new users with candy crunch flavors to help people quit smoking. You don’t need to put candy flavored nicotine at eye level of kids. This is why it is important to have some understanding of how research is done. Those few trials that show that SOME people could stop using combustible cigarettes when using e-cigarettes were done in smokers so committed to quitting that they enrolled in a clinical trial to try to quit. As someone who has participated in a clinical trial, let me tell you that, the questionnaires and visits are quite time consuming, and you often have to be dedicated to participate. Furthermore, behavioral interventions are also included, and I am quite sure that the local clerk at the gas station or corner store is not providing robust tobacco cessation advice to the person buying the Polar Mint or Watermelon Ice flavored e-cig and ensuring they talk to their doctor about the health effects of nicotine.

The tobacco industry has shown us over and over again that their playbook is addicting young brains to nicotine with flavors, masking the harshness of chemicals, and then crying “Freedom and choice” when attempts to interfere with their racket are introduced by communities. The newest play appears to be pretending concern for the health of adult smokers. As Prof Jordt said, the majority of smokers who want to quit can do it on their own, thank you very much. Those who do need additional support have a range of options, and maybe for some switching to e-cigarettes is a harm reduction strategy. We hope. But we don’t need to keep numbing the lungs with menthol and similar compounds to hide the toxic effects of what is being inhaled and drive new addictions. 

 

The FDA is planning to ban menthol in combustible cigarettes as they have other flavors, though they are dragging their feet. Hopefully a comprehensive federal flavor ban on e-cigarettes will be coming soon, but in the meantime, I hope one passes in my own state.

TLDR= Don't Mix Menthol and Toxins and Breathe them into your Lungs

To Do:

  • To hear more about Carrie’s story and about a county trying to protect its youth, listen to “A County vs Big Tobacco” from last season. Talk to your local or state policymakers to see if you can introduce a comprehensive flavor ban in your county or state. Don’t forget to include those new synthetic compounds that numb the lungs like mint but try to escape the “flavor” label! 
  • For more on the history of menthol and its targeting of children in general and the black community in particular, listen to the episode  “A Heartbreaking Trap” with youth pastor Ritney Castine.
  • For more on the odd shapes of e-cigs designed to be hidden in schools, you can look at the Tobacco Education Resource Library
  • To learn how to talk to young people in your life about e-cigarettes, listen to the first episode from this season, #DotheVapeTalk. You can also go to talkaboutvaping.org  for more resources. 
  • If you already use a flavored or menthol inhaled tobacco device and think it’s finally time to quit, check out the “Quit, Don’t Switch” campaign from the American Lung Association for other resources to help quit smoking.
  • Finally, please consider a donation to the American Lung Association, who employs wonderful people like Carrie, fighting hard to rid our communities of the scourge of Big Tobacco.

References:

Erythropel HC, Jabba SV, DeWinter TM, Mendizabal M, Anastas PT, Jordt SE, Zimmerman JB. Formation of flavorant-propylene Glycol Adducts With Novel Toxicological Properties in Chemically Unstable E-Cigarette Liquids. Nicotine Tob Res. 2019;21(9):1248-58. PubMed PMID: 30335174

Fan L, Balakrishna S, Jabba SV, Bonner PE, Taylor SR, Picciotto MR, Jordt SE. Menthol decreases oral nicotine aversion in C57BL/6 mice through a TRPM8-dependent mechanism. Tob Control. 2016;25(Suppl 2):ii50-ii4. PubMed PMID: 27698211

FDA.gov. “The Real Cost E-cigarette Prevention Campaign.” Jan 2023.

Jabba SV, Erythropel HC, Torres DG, Delgado LA, Woodrow JG, Anastas PT, Zimmerman JB, Jordt SE. Synthetic Cooling Agents in US-marketed E-cigarette Refill Liquids and Popular Disposable E-cigarettes: Chemical Analysis and Risk Assessment. Nicotine Tob Res. 2022 Jun 15;24(7):1037-1046.  

Jabba SV, Jordt SE. Risk Analysis for the Carcinogen Pulegone in Mint- and Menthol-Flavored e-Cigarettes and Smokeless Tobacco Products. JAMA Intern Med. 2019;179(12):1721-3

Leventhal AM, Tackett AP, Whitted L, Jordt SE, Jabba SV. Ice flavours and non-menthol synthetic cooling agents in e-cigarette products: a review. Tob Control. 2022 Apr 28 

Images taken from Stanford Research into Tobacco Advertising.