Cigarette additives have a range of purposes: to facilitate manufacture, increase shelf life, improve flavour and aroma and control burn rates, nicotine delivery and harshness/ irritation.1, 2 The main classes of additives and some examples of each are as follows:
- Processing aids facilitate the manufacture of cigarettes, such as by making cured tobacco less brittle. These include several ammonia compounds, carbon dioxide and ethyl alcohol.
- Combustion aids are used to control the smoking mechanics of cigarettes, such as by controlling the burning properties of cigarette paper. These include ammonium and sodium phosphate and sodium and potassium citrate.
- Flavour additives are used to improve the taste of cigarette smoke, either by introducing pleasant flavour 'notes' or masking unpleasant ones. These include liquorice, cocoa, honey, various fruit extracts and various spices.
- Humectants are used to keep tobacco moist and pliable. These include sugars, glycerine and glycol compounds.
- Preservativesprevent mould from growing on tobacco.
- Fillers arehemically inert substances, which are used to increase the bulk of the tobacco rod.
- Casings are substances sprayed on tobacco to improve its smoking quality. These include various sugars, liquorice and cocoa.
- Nicotine delivery regulators. Another reason for using additives is to facilitate the delivery of rewarding doses of nicotine. Ammonia compounds are added to some brands in order to increase the level of unprotonated nicotine in the smoke.
While 1 to 7 are classes of additives that the tobacco industry regularly refers to in its public communications about additives, using additives to regulate nicotine delivery is a matter about which the tobacco industry remains coy. It should also be noted that many additives are used for combinations of the aforementioned purposes. For instance, humectants, such as glycols, function to make tobacco more pliable, to increase the shelf life of cigarettes and to make the smoke taste smoother.3 They also have the effect of increasing smoke retention and may contribute to smoke particles penetrating deeper into the lungs. (1 ) Ammonia compounds make reconstituted tobacco sheet more pliable, improve flavour by reacting with various compounds in tobacco to produce a number of pleasant tasting sugars and also increase the level of unprotonated nicotine in the smoke.1
Since 2000 there has been a voluntary agreement between the Commonwealth and the tobacco manufacturers for the disclosure of the ingredients of Australian cigarettes.4 There are composite disclosures of hundreds of ingredients that companies say they potentially use. There are also brand-by-brand disclosures that list the major ingredients in descending order by weight. However, the industry claims that it cannot disclose all of the additives used in particular brands because that would mean giving up trade secrets and losing competitive advantage. Thus, it is not possible for consumers to know all of the ingredients used in each brand or the levels at which they are added.
During the period when 'low tar' cigarettes were believed to reduce intakes of harmful smoke constituents, there was a belief within tobacco control circles that additives could help make 'low tar' cigarettes more acceptable and thus contribute to reducing smokers' harmful intakes.1 After the emergence of the consensus that 'low tar' cigarettes do not provide relative health benefits, additives became subject to more critical attention. Advocates of regulation of additives have also argued for an extended concept of harm being used to judge whether specific additives are acceptable or not. Rather than the acceptability of particular additives hinging on whether they directly make cigarette smoke more toxic/ carcinogenic, the extended concept of harm also judges specific additives to be unacceptable if they make initiation easier and quitting more difficult.3
The tobacco industry claims that all of the potential ingredients in Australian cigarettes are 'generally regarded as safe' (or 'GRAS') for use as food and beverage ingredients by toxicologists. Consider the following quote from a Philip Morris document for informing the public and policymakers about cigarette additives:
'Most ingredients added to tobacco are flavourings that are added at very low levels (eg: less than ten ppm). When added at such low levels, these ingredients would not be expected to increase adverse effects over background effects caused by tobacco smoke alone.'(p6)
'All of the flavourings added to cigarette tobacco in the United States are approved as food additives by the FDA, or have been given the status Generally Regarded as Safe ('GRAS') by the FDA or other expert committees….
'All casings or humectants… are permitted for use in food by FDA; although a portion of casings or humectants may pyrolize, many of these same ingredients also pyrolize during the cooking of food.' p75
This document correctly claims that additives constitute a low proportion of the total weight of a cigarette and thus are unlikely to significantly affect toxicity/ carcinogenicity. Another way of putting this is that the toxins/ carcinogens present in cigarette smoke from burning tobacco swamp those from any other ingredients/ additives in cigarettes. (1) It is also correct that the additives used in cigarettes are overwhelmingly food products or approved food additives and are 'generally regarded as safe' for use in food and beverages. However, labelling cigarette ingredients as 'GRAS' glosses over the fact that these ingredients are vaporized or combusted and inhaled into the lungs, rather than ingested, as with food and beverages. It also glosses over the fact that these ingredients are generally used to facilitate the delivery of toxic/ carcinogenic and addictive smoke constituents by making cigarettes more attractive. They are generally not used for the purpose of decreasing the delivery of either toxic/ carcinogenic smoke constituents or addictive ones.
Smokers are not well informed that cigarette additives are generally food products, are generally not harmful in their non-combusted states and are unlikely to have substantial effects on the overall toxicity/ carcinogenicity of cigarette smoke.6 There is a widespread belief among smokers that cigarettes have dangerous chemicals added to them and could be made substantially less harmful if action was taken to prevent the tobacco industry from adding these chemicals. This stems from public confusion over whether harmful chemicals are found in smoke because they are deliberately added by the tobacco industry (which generally speaking is not true) and the harmful chemicals that are found in tobacco smoke because they are inevitably produced by the combustion of tobacco. Carter and Chapman (2006)6 reported that respondents in focus groups were very surprised to find out what the tobacco industry actually adds to cigarettes and for what purposes. Some respondents were also disbelieving of the information that additives are very 'ordinary' substances, like chocolate and sugar, rather than frightening ones, like 'jet fuel.' One response to the popular belief that cigarettes deliberately have dangerous chemicals added to them is to seek 'chemical free' means of smoking. Many roll-your-own smokers believe that roll-your-own tobacco is more 'natural' and does not contain additives like factory-made cigarettes do. They further believe that by virtue of being additive-free, roll-your-own cigarettes are less harmful. (See King 2010,7 in particular comments section for illustrative smoker responses.) However, these beliefs are not well founded. The available evidence is that roll-your-own tobacco has the same additives that are found in factory made cigarettes and, most importantly, that roll-your-own smokers will expose themselves to the same toxins/ carcinogens that factory-made cigarette smokers are exposed to and at much the same levels when smoking intensity is taken into account.8,9
Relevant news and research
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1. Bates C, McNeil A, Jarvis M and Gray N. The future of tobacco product regulation and labelling in Europe: implications for the forthcoming European Union Directive. Tobacco Control 1999;8(2):225–35. Available from: http://tobaccocontrol.bmj.com/cgi/content/full/8/2/225
2. Staunton D. Letter to Michael Wooldridge, Minister for Health and Family Services. Philip Morris, 1998. Available from: http://www.pmdocs.com/PDF/2064813389_3399_0.PDF
3. Wayne G and Connolly G. How cigarette design can affect youth initiation into smoking: Camel cigarettes 1983-93. Tobacco Control 2002;11(suppl.1):I32-I39. Available from: http://www.ncbi.nlm.nih.gov/pubmed/11893812
4. Commonwealth Department of Health and Ageing. Voluntary agreement for the disclosure of the ingredients of cigarettes. 16 June 2004, Commonwealth Department of Health and Ageing, 2000. Available from: http://www.health.gov.au/pubhlth/strateg/drugs/tobacco/agreement.pdf
5. Doull J, Frawley J and Glorge W. Ingredients added to tobacco in the manufacture of cigarettes by the six major American cigarette companies. Tobacco Reporter 1994;July 1994
6. Carter SM and Chapman S. Smokers and non-smokers talk about regulatory options in tobacco control. Tobacco Control 2006;15(5):398-404. Available from: http://tc.bmjjournals.com/cgi/content/abstract/15/5/398
7. King B. Think smoking rollies is 'safer'? Think again. The Age/ Sydney Morning Herald National Times, 2010:29 November. Available from: http://www.theage.com.au/opinion/society-and-culture/think-smoking-rollies-is-safer-think-again-20101126-18a65.html
8. Laugesen M, Epton M, Frampton C, Glover M and Lea R. Hand-rolled cigarette smoking patterns compared with factory-made cigarette smoking in New Zealand men. BMC Public Health 2009;9(1):194. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19538719
9. Shahab L, West R and McNeill A. A comparison of exposure to carcinogens among roll-your-own and factory-made cigarette smokers. Addiction Biology 2009;14(3):315–20. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19523045