Tobacco companies tout the “smooth,” “refreshing,” or “cold” experience when advertising menthol cigarettes, but new research suggests there’s more going on than a minty flavor.
Specifically, the sensation from menthol, in combination with the nicotine in tobacco, desensitizes receptors in the airways that are responsible for sensing nicotine irritation, according to a study published in the journal Molecular Pharmacology.
Researchers at Georgetown University discovered that the menthol used in cigarettes acts as a painkiller on the nerves that transmit the effects of cigarette smoke to the brain.
How Menthol Numbs the Airways
Nicotine is the physically addictive component in tobacco and prior research has established that it is also the primary agent responsible for irritating a person’s airways.
This irritation is what causes smokers to cough. It is also a contributor to emphysema, chronic obstructive pulmonary disorder (COPD), and cancer.
The new research out of Georgetown shows that menthol has an important pharmacologic effect on smokers.
The researchers examined menthol’s effects on the α3β4 nicotinic acetylcholine receptor (nAChR) in mice. These receptors occur all over the central nervous system and help transmit nicotine to the brain, which may also be involved in nicotine addiction and withdrawal, the researchers state.
"In addition to desensitizing the receptors in the lung and airways, menthol appears to slow or prevent the recovery of sensitivity after the first insult," the researchers say.
The study’s senior author Gerard Ahern, an associate professor of pharmacology at Georgetown University, said that besides desensitizing these receptors, menthol’s numbing effects prevent sensitivity from coming back.
"The issue may be that menthol in the presence of nicotine may reduce the irritation enough that a smoker can inhale more deeply, bringing not just nicotine but toxic smoke products farther into the lungs," Ahern said in a press release. "While beyond the scope of this study, it is possible that such deeper inhalation of menthol cigarettes, to the extent it occurs, increases the already substantial health harms from smoking."
Menthol Exempt From Cigarette Flavor Bans
Smoking is the leading cause of preventable death and disease in the United States, and government entities like the U.S. Centers for Disease Control and Prevention (CDC) keep smoking cessation as one of their top priorities.
With 99 percent of all smokers starting before age 26, there’s an increased focus to curb youth smoking habits. This included 2009 regulations from the U.S. Food and Drug Administration (FDA) that banned certain flavored cigarettes in the United States, including fruits, chocolate, and coffee. Menthol, however, was not among the banned flavors.
In July 2013, after reviewing the available research on menthol cigarettes, the FDA ruled: “the weight of evidence supports the conclusion that menthol in cigarettes is not associated with an increase in disease risk to the user compared to non-menthol cigarette smokers.”
A 2013 study from the CDC found that more than 40 percent of middle and high schoolers smoked flavored cigars or cigarettes, including menthol. Menthol and flavored cigarettes have been shown to get children to start smoking.
Besides children and teens, menthol cigarettes have been historically marketed toward African-American and other ethnic minority smokers by, according to the CDC, using “urban culture and language” and sponsoring “hip-hop bar nights with samples of specialty menthol cigarettes.”
Cancer rates in the African-American population remain higher than any other ethnic group of smokers, but trends show that more black men are quitting smoking compared to white men, according to the American Cancer Society.