TSNAs in Cigarettes and Cigarette Smoke: What Are They?

Tobacco Leaves Curing in Shed

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As of Dec. 20, 2019, the new legal age limit is 21 years old for purchasing cigarettes, cigars, or any other tobacco products in the U.S.

Tobacco-specific nitrosamines (TSNAs) are thought to be some of the most potent carcinogens in tobacco products. They are unique to tobacco and present in smokeless tobacco, snuff, cigarettes, and electronic cigarette liquid. Most of the damage comes from cigarettes and cigarette smoke, however, because of the prevalence of smoking.

While it is the nicotine in cigarettes that causes addiction, other chemicals in tobacco products have a detrimental impact on health. Understanding the risks that come from these compounds may help you recognize the importance of quitting smoking or avoid smoking in the first place.

This article discusses what TSNAs are and the impact they have on the body. It also covers how and why these compounds should be removed from all tobacco products.

What Are TSNAs and Where Do They Come From?

The International Agency for Research on Cancer (IARC) has identified eight tobacco-specific nitrosamines in tobacco and tobacco smoke. Two of them have been classified as Group 1 carcinogens, which means they cause cancer in people:

  • N-nitrosonornicotine (NNN)
  • 4-methyl-N-nitrosamino-1-(3-pyridyl)-1-butanone (NNK)

A metabolite of NNK, NNAL is also a strong carcinogen and has been found in the urine of people exposed to secondhand smoke, whether they smoke or not.

From Nitrates to Nitrosamines

Green tobacco coming out of the field will contain nitrates from fertilizers used in farming, and to a lesser degree, from the earth plants they were grown in. It doesn't yet contain TSNAs.

Nitrates in tobacco leaves are transformed into dangerous tobacco-specific nitrosamines (TSNAs) when tobacco (and the nicotine in it) is fermented and cured. This processing can be done in a couple of ways, by air or heat, and the results will produce either high or low levels of nitrosamines.

TSNAs are present in finished tobacco products and ultimately make their way into the bodies of people who smoke, where they contribute to numerous forms of cancer.

Recap

It is the fermenting and curing process used to create tobacco products that convert the naturally-ocurring nitrates in tobacco leaves into cancer-causing nitrosamines.

How Do TSNAs Hurt Smokers?

TSNAs are strong carcinogens that are linked to several cancers. Lung cancer, specifically adenocarcinoma (the most common form of lung cancer), has been shown to be closely linked to NNK.

Other cancers associated with TSNAs include:

  • Esophageal cancer
  • Liver cancer
  • Oral cancer
  • Pancreatic cancer

There is a growing concern that TSNAs may also be associated with cervical cancer because these carcinogens have been found in large quantities in the cervical mucus of women who smoke.

While TSNAs are not directly linked to mental health issues, understanding the health risks of these compounds is important for anyone who smokes tobacco products. Recognizing that these compounds are closely linked to several different types of cancer may help give you the motivation you need to quit smoking for good.

TSNAs Can (and Should) Be Reduced in Tobacco Products

Researchers know that TSNA levels in commercial cigarettes vary greatly worldwide. According to the American Cancer Society, higher TSNA levels in tobacco products lead to higher cancer risk for the people who use them.

The reasons why TSNA levels vary so much is multi-faceted. Tobacco type, agricultural conditions in tobacco farming, and how the tobacco is cured once it comes out of the field all play a role in the amount of cancer-causing nitrosamines present in finished tobacco.

Burley tobacco (also known as White Burley tobacco) and the flue-curing method appear to produce the highest amount of TSNAs, according to researchers.

The Family Smoking Prevention and Tobacco Control Act gives the Food and Drug Administration (FDA) the power to regulate tobacco products. Researchers are calling for standards of manufacture that would reduce the levels of highly carcinogenic TSNAs to be put in place for commercial tobacco products.

Recap

Researchers suggest that TSNA levels can and should be reduced in commercially available tobacco products. Creating manufacturing standards could potentially help lower the cancer risk associated with these products.

How Is Tobacco Cured?

The curing process itself can play a major role in the TSNA content of a tobacco product. Some of the different curing methods that are used to process the tobacco used in cigarettes and other products include the following.

Air-Curing

This process involves hanging tobacco leaves in a barn with good airflow. The tobacco is left to dry slowly over a period of one to two months. Air-curing produces a low sugar, high nicotine tobacco. Cigar and burley tobaccos are air-cured.

Flue-Curing

This is a process in which fresh tobacco leaves are hung on poles in an enclosed barn and cured with the heat of a flue connected to an external firebox. This process cures the tobacco by heat without exposing it to smoke.

In the 1960s, the firebox was replaced with a gas-fed heat source. This curing method produces tobacco that is high in sugar content and medium to high nicotine content. Most commercial cigarettes are flue-cured.

Fire-Curing

In this curing process, a smoldering hardwood fire is inside the barn with the tobacco. Fire-cured tobacco can take days or weeks depending on the tobacco and what it's being prepped for.

Pipe, chew, and snuff tobacco are fire-cured. Some cigarettes are also produced from fire-cured tobacco. Fire-cured tobacco is low in sugar and high in nicotine.

Sun-Curing

This involves exposing tobacco leaves to the sun for drying. Used in Mediterranean countries, this method produces what is known as Oriental tobacco. It is low in sugar and nicotine.

Turkish cigarettes are 100% unblended Oriental tobacco. Cigars, pipe tobacco, snuff, and chew are also made with Oriental tobacco.

The factors that influence the levels of TSNAs in tobacco and tobacco smoke can and should be controlled to protect smokers and non-smokers exposed to cigarette smoke as much as possible.

Other Carcinogenic Compounds in Tobacco

In addition to TSNAs, 10 highly carcinogenic chemicals known as PAHs and aromatic amines are also thought to play a leading role in the risk of certain cancers in people. Both TSNAs and PAHs can be reduced in tobacco products.

To date, science has revealed approximately 70 carcinogenic compounds in cigarettes and cigarette smoke, including 60 that are present in cigarette smoke and at least 16 that reside in unburned tobacco.

The IARC lists 10 PAHs, 8 TSNAs, and 45 other carcinogens as potential human carcinogens, and research continues.

Understanding the Risks

Tobacco kills one in five adults around the world today, amounting to approximately 6 million lives lost annually to a cause that is within our control.

The Centers for Disease Control and Prevention (CDC) reports that cigarette smoking causes more than 480,000 deaths per year in the United States. Of those deaths, 41,000 are the result of secondhand smoke. 

Education about the hazards of tobacco use and support for people quitting is key to reversing this trend.

When You Want to Quit Smoking

Knowing the risks of TSNAs and other dangerous compounds found in cigarettes and other tobacco products may help you better understand the importance of not smoking. Research suggests that most people who smoke report that they want to quit.

The challenges associated with quitting, including the unpleasant symptoms of nicotine withdrawal, can make quitting much more difficult. The nicotine found in tobacco is highly addictive, but there are resources available that can help you quit smoking successfully. 

Many people are not sure exactly how to quit smoking, but thankfully, you don't have to do it alone. When you're ready to quit:

  • Learn more about the risks of smoking: Recognizing the physical and mental health damage caused by cigarettes can help give you the incentive to stick to your smoking cessation goals.
  • Develop a smoking cessation plan: Research the tools and resources that are available and decide what approach will work best for you. Set a quit date and get together the things you will need to have on hand to be successful.
  • Consider a quit smoking aid: There are a number of quit smoking aids available including nicotine replacement therapy (NRT) and prescription smoking cessation medications. Using these products can significantly improve your chances of quitting successfully.
  • Try a quit smoking app: There are a number of quit smoking apps that can help you track your progress, find motivation, explore helpful information, and connect with other people who are also trying to quit.

There's no one size fits all approach that works for everyone who is trying to quit smoking. It can be challenging, but having a plan and utilizing effective quit smoking aids can help you achieve your goals of giving up cigarettes and tobacco. It's never too late to quit and the sooner you do, the sooner you can begin to heal from the damage caused by TSNAs and the other harmful compounds found in cigarettes.

Recap

Quitting smoking isn't easy, but using quit smoking aids and supportive resources can help you stick to your goals.

Summary

TSNAs, which stands for tobacco-specific nitrosamines, are dangerous carcinogens that are created when tobacco is fermented and cured. They are found in tobacco products including cigarettes, snuff, e-cigarette liquid, and smokeless tobacco. TSNAs are linked to several cancers including lung, oral, liver, esophageal, pancreatic, and cervical cancer. Recognizing these risks can be an important step in the smoking cessation process.

A Word From Verywell

There is no safe level of exposure to cigarette smoke. It is toxic air, and when it settles on surfaces, it creates toxins known as third-hand smoke.

If you are still smoking and want to quit, start by considering the reasons why you should. Health risks associated with TSNAs and other compounds are just one compelling reason for quitting.

Quitting tobacco takes work, but the discomforts are temporary. Don't fear smoking cessation. Think of it as a stepping stone to a much better life.

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9 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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