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New Toxins Found in Smokeless Tobacco

21 New Toxins and Carcinogens Identified in Smokeless Tobacco

By Jennifer Warner
WebMD Health News

Reviewed By Louise Chang, MD

Aug. 14, 2009 -- A single pinch of snuff may expose the user to the same amount of dangerous smoke-related chemicals found in the smoke of five cigarettes, according to a new study highlighting the harmful effects of smokeless tobacco.

Researchers have identified new toxins and cancer-causing substances in smokeless tobacco and snuff, in addition to other known carcinogens, such as nitrosamines.

Researchers say sales of moist snuff have doubled since the 1980s, and that many smokeless tobacco users mistakenly believe the products are less hazardous to their health because they do not expose the user to tobacco smoke.

But their study, presented today at a meeting of the American Chemical Society, shows some of the most popular smokeless tobacco and snuff brands contain an additional 21 smoke-related polycyclic aromatic hydrocarbons (PAH), which are potent toxins and carcinogens.

"This study once again clearly shows us that smokeless tobacco is not safe," researcher Irina Stepanov, PhD, of the University of Minnesota at Minneapolis, says in a news release. "Our finding places snuff on the same list of major sources of exposure to polycyclic aromatic hydrocarbons as smoking cigarettes."

Smoke Hazards in Smokeless Tobacco

PAH are common environmental contaminants that form as the result of incomplete burning of carbon-containing materials, such as wood, coal, and fat. For example, PAH form during the grilling of hamburgers, steaks, and other red meat.

Stepanov says that until recently, researchers thought smokeless tobacco contained only trace amounts of PAH because the tobacco was not burned when used.

"Even though smokeless tobacco use does not involve burning, moist snuff is getting contaminated with PAH during its manufacturing," Stepanov says. She says a fire-curing process is used to turn tobacco leaves into snuff, which puts tobacco in direct contact with the smoke of smoldering hardwoods.

Researchers say the levels of PAH found by this study in smokeless tobacco make them the most prevalent group of carcinogens in moist snuff.

According to the National Cancer Institute, smokeless tobacco contains 28 cancer-causing substances. Oral cancers are linked to use of smokeless tobacco. Per dose, more nicotine from smokeless tobacco is absorbed than from a cigarette. Use of smokeless tobacco can also lead to nicotine addiction.

SOURCES: 238th National Meeting of the American Chemical Society, Washington, D.C., Aug. 16, 2009. News release, American Chemical Society. National Cancer Institute: "Smokeless Tobacco and Cancer: Questions and Answers."

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