Nil By Mouth: Sokeless Tobacco Kills

The discovery of a new range of cancer-causing chemicals in smokeless tobacco has backed up advice that it's not a "safe" alternative to cigarettes.

Called polyaromatic hydrocarbons (PAHs), the chemicals contaminate smoke from cigarettes and wood fires, but were assumed to be absent from smokeless tobacco products such as moist snuff because users hold it in their mouths – between lip and gum – rather than burning it.

Now researchers have found that popular moist snuff products on sale in the US contain at least 22 PAHs, probably because the tobacco is exposed to wood smoke during its curing process.

Moist snuff, also called snus, is mostly used in North America and Scandinavia, but is banned from sale in all European Union countries except Sweden.

Five pack

A typical dose of moist snuff has the same PAH content as five cigarettes, said Irina Stepanov of the University of Minnesota in Minneapolis as she presented the findings at the annual meeting of the American Chemical Society on 16 August in Washington DC.

Moist snuff consumption, which doubled in the US between 1986 and 2005, has been linked with increased risks of mouth and pancreatic cancers. The PAHs add to 28 cancer-causing chemicals including nicotine and nitrosamines previously identified in the snuff.

"The use of smokeless tobacco carries very serious risks and the new findings on PAH levels underscore this," says David Hammond of the University of Waterloo in Ontario, Canada, who monitors the safety of tobacco products. He warns, however, that smoke from cigarettes remains the biggest tobacco-related cancer risk.