WASHINGTON, Aug. 16, 2009 — Attention all smokeless
tobacco users! It's time to banish the comforting notion that snuff
and chewing tobacco are safe because they don't burn and produce
inhalable smoke like cigarettes. A study that looked beyond the
well-researched tobacco hazards, nitrosamines and nicotine, has
discovered a single pinch –– the amount in a portion
–– of smokeless tobacco exposes the user to the same
amount of another group of dangerous chemicals as the smoke of five
cigarettes.
The research on polycyclic aromatic hydrocarbons (PAH) in
smokeless tobacco was reported here today at the 238th National
Meeting of the American Chemical Society (ACS). It adds to existing
evidence that smokeless contains two dozen other carcinogens that
cause oral and pancreatic cancers, the scientists say.
"This study once again clearly shows us that smokeless tobacco
is not safe," said Irina Stepanov, Ph.D., who led the research
team. "Our finding places snuff on the same list of major sources
of exposure to polycyclic aromatic hydrocarbons as smoking
cigarettes." PAHs are widespread environmental contaminants formed
as a result of incomplete burning of wood, coal, fat in meat, and
organic matter. PAHs form, for instance, during the grilling of
burgers, steaks and other meat.
The findings come in the midst of a rise in both marketing and
consumption of smokeless tobacco, which many consumers regard as
less dangerous than other forms of tobacco. Estimates suggest that
sales of moist snuff in the United States have doubled since the
1980s.
"The feeling of safety among some smokeless users is wrong,"
said Stepanov, a chemist with Masonic Cancer Center, University of
Minnesota, Minneapolis. "A total of 28 carcinogens were identified
in smokeless tobacco even before our study. Continued exposure to
these over a period of time can lead to cancer. Now we have found
even more carcinogens in snuff." In addition to the heightened
cancer risk, she noted that chronic use of snuff leads to nicotine
addiction, just as it does with cigarette smoking.
Stepanov said that until recently, scientists believed that only
trace amounts of PAH existed in snuff because the tobacco was not
burned when used. This assumption proved to be wrong. "Even though
smokeless tobacco use does not involve burning, moist snuff is
getting contaminated with PAH during its manufacturing," according
to Stepanov. The most likely source of this contamination with PAH
is the curing process that is used to turn tobacco leaves into
snuff. This process is called 'fire-curing', and it puts tobacco
into direct contact with the smoke generated by smoldering
hardwoods –– a rich source of various PAHs.
Looking to the next project, she said the team is working on a
study that will examine a wide range of smokeless tobacco brands to
compare PAH levels among them.
SOURCE