What Is The Role Of Menthol In Tobacco Reinforcement And Addiction?

 

Cigarette smoking is a public health burden that especially harms individuals with psychiatric conditions and socioeconomic disadvantage and is a major contributor to health disparities. Reducing this burden will require tobacco control and regulatory policies that are more effective at changing behavior in these vulnerable populations.

Despite the overall decline in the prevalence of cigarette use in the United States, menthol cigarette use among smokers is rising, and evidence shows that it may lead to more detrimental effects on public health than regular cigarette use. Fine Organics is among the largest manufacturer of Menthol Crystals in India and internationally. One of the mechanisms by which nicotine sustains tobacco use and dependence is due to its cognitive enhancing properties, and basic science literature suggests that menthol may also enhance nicotine's acute effect on cognition.

It is well documented that tobacco use is highly addicting. Nicotine is the psychoactive substance in tobacco that produces tobacco addiction and serves as a potent and powerful reinforcer in both humans and animals . While nicotine is the primary psychoactive component that makes tobacco addicting, the World Health Organization in their technical report series has identified several additives such as menthol in the manufacturing of cigarettes to specifically reduce the smoke harshness, leading the smoker to possibly take in more toxic and dependence-causing smoke constituents. These additives may alter the attractiveness and/or ease of use of the product and contribute to the perception that cigarettes are less harmful. These additives may also have important implications for addiction risk and motivation to quit. A recommendation by WHO was to regulate “contents and designs that contribute to consumer appeal and palatability” since they contribute to “effects on tobacco use initiation, patterns of use, product selection, and persistence of use.” They further recommended the importance of educating menthol cigarette smokers that additives “are masking the harshness of cigarette emissions and allowing them to bypass the body's normal defense mechanisms for preventing exposure to detrimental substances.”

Smoking any kind of cigarette, including menthol cigarettes, is harmful and increases risk for serious illness and death. Studies have shown that menthol in cigarettes likely leads people—especially young people—to experiment with smoking. It also could increase a young person’s risk of becoming dependent on nicotine. Compared to adults who smoke non-menthol cigarettes, adults who smoke menthol cigarettes make more attempts to quit smoking and have a harder time quitting.

Reinforcing Sensory Effects Of Menthol in Cigarettes

As stated above, nicotine is a powerful reinforcer that leads to continuous tobacco use and addiction. Menthol may increase the strength or sensory impact of nicotine, thus increasing the reinforcing effects of nicotine in tobacco.  The sensory effects of menthol in cigarettes are critical in understanding the smoker's subjective experience and how that can contribute to the reinforcing effects of smoking. Internal tobacco industry documents have shown that sensory impact is enhanced when small concentrations of menthol are combined with nicotine and depressed with larger concentrations or after extended exposure to menthol.  A number of studies have revealed that smokers of menthol cigarettes report smoking these cigarettes because of the characteristic cool minty taste compared with nonmenthol cigarettes . These findings suggest that it is particularly important to understand the influence of menthol as a cigarette additive from the perspective of the menthol cigarette smoker.

The reinforcing sensory effects of menthol cigarettes have been examined from multiple perspectives. Descriptions of positive early smoking experiences with menthol cigarettes suggest that menthol cigarettes may facilitate smoking initiation. The taste of menthol in cigarettes may serve as a reinforcer of smoking behavior as “taste” was expressed overwhelmingly as the reason for smoking this type of cigarette among Black focus group participants. Menthol appears to increase the rewarding or reinforcing effects of nicotine, thus possibly increasing the likelihood of becoming dependent on nicotine.

In the 1920s, tobacco companies created a marketing campaign for what would one day be their most profitable series of products: mentholated tobacco cigarettes. Menthol provides the smoker with a pleasant mint flavor in addition to a cooling sensation of the mouth, throat, and lungs, giving relief from the painful irritation caused by tobacco smoke. Promising a healthier cigarette using pictures of doctors in white coats and even cartoon penguins, tobacco companies promoted these cigarettes to young, beginner smokers and those with respiratory health concerns. Today, smoking tobacco cigarettes causes one in five US Americans to die prematurely, crowning it as the leading cause of preventable death. In contrast to the dubious health claims by tobacco companies, mentholated cigarettes are in fact more addictive. Smokers of mentholated cigarettes have lower successful quit rates and in some cases are resistant to both behavioral and pharmacological treatment strategies. There is now considerable evidence, especially in the last 5 years, that suggest menthol might influence the addictive potential of nicotine-containing tobacco products via biological mechanisms. First, menthol alters the expression, stoichiometry, and function of nicotinic receptors. Second, menthol's chemosensory properties operate to mask aversive properties of using tobacco products. Third, menthol's chemosensory properties aid in serving as a conditioned cue that can both enhance nicotine intake and drive relapse. Fourth, menthol alters nicotine metabolism, increasing its bioavailability.

Mentholated cigarettes gained popularity in the 1950s and were often marketed as "healthy" cigarettes, attributable to their pleasurable mint flavor and cooling sensation in the mouth, lungs, and throat. While it is clear that nicotine is the primary psychoactive component in tobacco cigarettes, recent work has suggested that menthol may also play a role in exacerbating smoking behavior, despite original health claims. Recent evidence highlights four distinct biological mechanisms that can alter smoking behavior: 1) menthol acts to reduce the initially aversive experiences associated with tobacco smoking; 2) menthol can serve as a highly reinforcing sensory cue when associated with nicotine and promote smoking behavior; 3) menthol's actions on nicotinic acetylcholine receptors may change the reinforcing value of nicotine; and 4) menthol can alter nicotine metabolism, thus increasing nicotine bioavailability. The effects of menthol cigarette use in increasing the reinforcing effects of nicotine on smoking behavior were evidenced in both qualitative and quantitative empirical studies. These findings have implications for enhanced prevention and cessation efforts in menthol smokers.