The Tobacco Additives
That Keep You Hooked
By Rosie Waterhouse
The Telegraph - UK
Additives in cigarettes may make some brands far more addictive than others, according to research.
For the first time, scientists have measured the amount of super-addictive "freebase" nicotine cigarettes deliver to the smoker.
Like crack cocaine, freebase nicotine vaporises and passes rapidly through the lungs into the bloodstream. Because it reaches the brain so quickly it is thought to be more addictive than normal nicotine.
The research, by a team at Oregon Health and Science University in Portland, could lead to ways of rating the addictiveness of different brands.
Scientists compared 11 brands available in America. They found that some contained 10 to 20 times higher percentages of freebase nicotine than experts had previously believed.
Brands were compared with a laboratory "reference" cigarette containing one per cent freebase nicotine. They varied greatly, ranging from one per cent or two per cent to 36 per cent for a speciality US brand called American Spirit. Marlboro contained up to 9.6 per cent freebase nicotine. Other well known brands included Camel (2.7 per cent), Winston (five per cent to 6.2 per cent) and Gauloises Blondes (5.7 per cent to 7.5 per cent).
Professor James Pankow, who led the study, reported in the journal Chemical Research in Toxicology, said: "During smoking, only the freebase form can volatise from a particle into the air in the respiratory tract. Since scientists have shown that a drug becomes more addictive when it is delivered to the brain more rapidly, freebase nicotine levels in cigarette smoke thus are at the heart of the controversy regarding the tobacco industry's use of additives like ammonia and urea, as well as blending choices in cigarette design."
A 1997 study led by Prof Pankow linked ammonia additives with increased freebase nicotine levels in cigarettes. He found that on its own, nicotine would not be very potent in the body but ammonia strips away protons from surrounding molecules including nicotine, making it more rapidly absorbed.
The 1997 research confirmed assertions made by the American Food and Drug Administration that widespread use of ammonia compounds in cigarettes manufacturing was evidence that the industry manipulated the delivery of nicotine in tobacco products.
Professor Jack Henningfield, from the Johns Hopkins University School of Medicine in Baltimore, Maryland, said: "It appears likely that ingredients used in modern cigarette manufacture, such as ammonia and urea, account for this addiction-enhancing effect."
Professor Pankow said that in the United States there were no formal tobacco industry or Food and Drug Administration guidelines on appropriate levels of freebase nicotine in cigarettes. But the message from the industry was that cigarettes contained only small percentages of freebase nicotine. Only additives on a permitted list from the Department of Health are allowed in cigarettes made in Britain.
A spokesman for the Tobacco Manufacturers' Association in the UK said: "Cigarettes manufactured here do abide by the permitted list and may be quite different from those in America."
A spokesman for Phillip Morris, the maker of Marlboro, said: "Ammonia is a compound naturally present in tobacco leaf. Quite simply, there is no safe cigarette. No one cigarette is any more or less harmful or addictive than another. All cigarettes and their smoke are harmful and addictive.
"It is entirely inappropriate to start communicating to consumers that there are distinctions in terms of harm or addictiveness between various brands of cigarettes. If consumers are concerned about the harm or addictiveness of smoking they should quit."
Three men who featured as the most famous character in tobacco advertising - the horse-riding Marlboro Man - have died from smoking-related illnesses: David Millar Jnr in 1987 from emphysema, Wayne McLaren in 1992 after lung cancer spread to his brain, and David McLean in 1995 from lung cancer.