Nicotine is addictive, drives tobacco dependence; nicotine patches cannot be replaced by eggplants

Tobacco remains a leading cause of preventable death worldwide, responsible for over eight million deaths annually, according to the World Health Organization (WHO). Despite a decline in usage—from roughly 1.36 billion users in 2000 to 1.25 billion in 2022—the risks associated with tobacco continue to be significant. All forms of tobacco, whether smoked, chewed, or sniffed, are harmful, with even smokeless products containing carcinogenic (cancer-causing) compounds that endanger health. Tobacco smoke also irritates and inflames the airways, which can lead to chronic bronchitis and emphysema.

Tobacco is derived from Nicotiana tabacum and Nicotiana rustica, plants native to the Americas that were later spread globally by European colonists. Central to tobacco’s effects is nicotine, a psychoactive compound that tobacco users often credit for feelings of relaxation, increased energy, or improved focus. Nicotine is also used in nicotine replacement therapy, such as patches, which deliver controlled doses to help people quit smoking.

Recently, chiropractor Bryan Ardis claimed that “nicotine is not addictive” in a video excerpt that was viewed more than 200,000 times on Facebook and Instagram.

Ardis also claimed that consuming eggplants could replace nicotine patches because they “have the second-highest natural nicotine content”. He further alleged that “every virus on earth […] targets nicotine receptors” and that nicotine could be used as a cure against all of these viruses.

These claims are inaccurate, as we will show below.

Nicotine is an addictive substance

Numerous health agencies and medical associations directly contradict Ardis’ claim. The U.S. National Institute on Drug Abuse explained that “most smokers use tobacco regularly because they are addicted to nicotine” and defines addiction as “compulsive drug-seeking and use, even in the face of negative health consequences”.

Both the Cleveland Clinic and the U.S. Food and Drug Administration (FDA) called nicotine a “highly addictive chemical”. This is also the view of the American Chemical Society and of the American Cancer Society.

Nicotine’s addictive nature stems from its ability to stimulate the release of dopamine, a neurotransmitter that plays a central role in the brain’s reward system. As the Cleveland Clinic explains:

“This system is designed, from an evolutionary standpoint, to reward you when you’re doing the things you need to do to survive — eat, drink, compete to survive and reproduce. As humans, our brains are hard-wired to seek out behaviors that release dopamine in our reward system. When you’re doing something pleasurable, your brain releases a large amount of dopamine. You feel good and you seek more of that feeling.”

When tobacco is smoked or chewed, nicotine is rapidly absorbed into the bloodstream and transported to the brain. There, it binds to nicotinic acetylcholine receptors (also known as nicotinic cholinergic receptors) on the surface of neurons. This interaction triggers a cascade of neuronal activity that leads to the release of dopamine^[1]. Dopamine creates sensations of pleasure, calm, and increased alertness, which reinforce the desire to continue consuming nicotine.

As nicotine’s effects wear off, dopamine levels drop, leaving the user feeling irritable and anxious. This drives the individual to seek more nicotine to regain the pleasurable effects, creating a cycle of dependence. Over time, this cycle conditions the brain to expect nicotine, leading to addiction.

The addictive potential of nicotine is underscored by experiments in which participants were given the option to self-administer nicotine or a placebo intravenously. The majority of participants consistently chose nicotine over the placebo, demonstrating its strong reinforcing properties^[1,2].

This biological mechanism highlights why nicotine is addictive and a key factor in smoking addiction. Ardis’ claim that “nicotine is not addictive” is simply false.

Eggplant contain nicotine, but not enough to replace nicotine patches

Eggplant and tobacco both belong to the Solanaceae family, or nightshade family, together with mandrake, belladonna, tomatoes, potatoes, and others. As such, they share some common features, including the presence of nicotine.

In his video, Ardis shared a table of nicotine content in various nightshade plants, showing that eggplants contain 100 nanograms of nicotine per one gram (ng/g) of eggplant^[3].

The nicotine amount in eggplants is indeed higher than in the other plants listed in the table. However, this isn’t enough to replace nicotine patches, as Ardis claimed. Nicotine patches are one type of nicotine replacement therapy where a low amount of nicotine is slowly released in the blood. The aim is to reduce the symptoms of withdrawal and craving that come when a user attempts to quit smoking.

The U.S. Centers for Disease Control and Prevention (CDC) indicate that nicotine patches release 7 to 21 milligrams (mg) of nicotine per day. That’s equivalent to 7 to 21 million nanograms of nicotine per day. Considering the nicotine concentration in eggplants, one would need to eat between 70 to 210 kilograms of eggplant per day to substitute for a nicotine patch. It’s easy to see that consuming this amount of eggplant daily isn’t plausible for a person.

Nicotine receptors aren’t the target of all known viruses

Ardis’ claim that all viruses target the nicotine receptor suggests that viruses allegedly latch onto the nicotinic acetylcholine receptors mentioned earlier. Ardis mentioned some viruses as examples: measles, mumps, rubella, polio, herpes, human immunodeficiency virus (HIV), and rabies. However, this claim is inaccurate.

To illustrate this, we can use some of the viruses from Ardis’ list as examples.

HIV, the virus that causes acquired immunodeficiency syndrome (AIDS), doesn’t target the nicotinic receptors to infect cells. It binds to a molecule called CD4 located at the surface of T lymphocytes, a type of white blood cell. This allows the virus to enter the cells and to begin proliferating.

Measles, a highly contagious virus particularly dangerous to children, binds to three different molecules called SLAM, CD46, and nectin-4 and infects different cell types, including immune cells and those that line the outer surface of the body and inner surface of blood vessels^[4].

Poliovirus is a highly contagious virus that is usually transmitted through the oral-fecal route. In some cases, the virus can affect the nervous system and cause irreversible paralysis. Poliovirus infects cells by targeting a protein on cells called PVR, for Poliovirus Receptor^[5].

Mumps is a virus mostly affecting children that infects salivary glands and can spread to the rest of the body. It penetrates the cells by targeting complex sugar-based molecules at the cell surface called glycans^[6].

It should be mentioned that at least one virus does target nicotinic receptors. Indeed, rabies infects neurons by targeting several types of nicotinic cholinergic receptors^[7].

Furthermore, there is no evidence that nicotine is a universal cure. Some preliminary results suggests that the activation of a subtype of nicotinic receptor could mitigate infections by specific viruses (herpes virus and zika virus)^[8,9]. But these results were obtained in lab animals or in cells grown in the Petri dish. This doesn’t show that the same effect occurs in humans, nor that it cured the disease.

In conclusion, it indicates that nicotinic receptors may be the target of some, but not all viruses. And there is no clinical evidence that nicotine cures all viral infections, contrary to claim.

Conclusion

Contrary to Ardis’ claims, nicotine is an addictive molecule that stimulates the brain’s reward system by inducing short bursts of dopamine secretion. Regular nicotine exposure, like from tobacco smoking, encourages repeated use and leads to withdrawal symptoms when nicotine is absent. These effects make nicotine a key factor in tobacco addiction and the significant health risks associated with it.

Although other nightshade plants, like eggplant, contain nicotine, the amount isn’t enough to replace nicotine replacement therapies such as nicotine patches, which are specifically designed to help manage withdrawal and craving symptoms that tobacco users experience when attempting to quit.

REFERENCES

• 1 – Wills et al. (2022) Neurobiological Mechanisms of Nicotine Reward and Aversion. Pharmacological Reviews.
• 2 – Sofuoglu et al. (2007) Self-Administration of Intravenous Nicotine in Male and Female Cigarette Smokers. Neuropsychopharmacology.
• 3 – Domino et al. (1993) The Nicotine Content of Common Vegetables. The New England Journal of Medicine.
• 4 – Hashiguchi et al. (2011) Measles virus hemagglutinin: structural insights into cell entry and measles vaccine. Frontiers in Microbiology.
• 5 – Bowers et al. (2018) Poliovirus Receptor: More than a simple viral receptor. Virus Research.
• 6 – Kubota & Hashiguchi (2021) Unique Tropism and Entry Mechanism of Mumps Virus. Viruses.
• 7 – O’Brien et al. (2024) The human alpha7 nicotinic acetylcholine receptor is a host target for the rabies virus glycoprotein. Frontiers in Cellular and Infection Microbiology.
• 8 – Zhao et al. (2024) Activation of nicotinic acetylcholine receptor α7 subunit limits Zika viral infection via promoting autophagy and ferroptosis. Molecular Therapy.
• 9 – Chen et al. (2024) α7 nicotinic receptor activation mitigates herpes simplex virus type 1 infection in microglia cells. Antiviral Research.