A research team from Yale and the University of Connecticut has found that the cooling effect of menthol may actually cause people to smoke more and become addicted to cigarettes because it reduces the protective respiratory response to irritants in cigarette smoke.
The study appears online in the Journal of the Federation of American Societies for Experimental Biology (FASEB).
Menthol, the cooling agent in peppermint, is added to almost all commercially sold cigarettes these days, in varying degrees. Sven-Eric Jordt, associate professor pharmacology at the Yale University School of Medicine, said he long believed the soothing ingredient played a role in smokers’ addictions — particularly new or young smokers. The main ingredients in cigarettes are naturally irritating, he said, often prompting such reactions as coughing or sneezing.
“There was always a suspicion that tobacco companies added menthol as a kind anesthetic to make it easier for beginning to inhale this irritating smoke,” Jordt said. “We hypothesized that this might be why menthol cigarettes are popular with new smokers.”
The study, which lasted about a year, examined the effect of menthol on mice. About 80 to 100 mice total were used in the study, Jordt said.
Researchers found that in mice, inhaled menthol immediately abolished the response in airway receptors that promote sensations of irritation to protect the respiratory system. The mouse equivalent of a “smoker’s cough” was almost completely blocked when mice inhaled menthol and tobacco irritants together.
In 2009, Congress passed the Family Smoking Prevention and Tobacco Control Act, which outlawed flavored tobacco additives such as cloves, cinnamon, candy, chocolate or fruit flavors. But menthol was specifically exempted from the ban. The Food and Drug Administration is currently evaluating scientific data on menthol, however, and could decide to ban it as well if it is deemed harmful.
Other authors are John B. Morris, Michael A. Ha and Daniel N. Willis of the University of Connecticut, and Boyi Liu of Yale. This study was supported by the National Institutes of Health and the American Asthma Foundation.