Select Committee on Health Minutes of Evidence


Memorandum by British American Tobacco

THE TOBACCO INDUSTRY AND THE HEALTH RISKS OF SMOKING (TB 28)

INGREDIENTS

  214.  British American Tobacco recognises that it is important to assess the use of ingredients.

  215.  Ingredients are sometimes added to tobacco during the manufacture of cigarettes, and can also be added to the filter or cigarette paper. Many of the ingredients are used to give flavour and maintain freshness. They have also been used to enhance the performance of filters, to control the burn rate of paper and to achieve other design goals.

  216.  There are three basic types of ingredients which are added to tobacco: casings, such as corn syrup, honey or molasses, which reduce the harshness of smoke and enhance taste; humectants, such as glycerol, which stabilise moisture content and reduce staleness; and specific flavourings, often derived from natural herbs or spices, or their essential oils, such as menthol, which are used to give the smoke a distinctive taste.

  217.  The use of some traditional ingredients, such as liquorice, can be traced to the 16th century. Most ingredients added to cigarettes have a long history of use in foods, beverages and other consumer products, including tobacco.

  218.  Use of ingredients, especially flavourings, is not consistent across different styles of cigarette, or across different markets. The style of cigarette most popular in the UK (as well as Canada, Australia, and many other countries) is essentially a Virginia-blend product, and its consumers do not expect, or generally appreciate, strong, pungent flavours and aromas. Few, if any, ingredients are added to many cigarettes made in this style.

  219.  Cigarettes containing Burley tobacco, including US-style cigarettes, have traditionally been flavoured, not least to ameliorate their somewhat harsher smoke. Consumers of such cigarettes expect strong, distinctive flavours, as of course do consumers of certain European-style cigarettes such as those found in France. In different countries around the world, different flavours are expected and appreciated by smokers.

  220.  British American Tobacco's most popular international brand is State Express 555. It is a Virginia-blend cigarette, sold around the world. It is mainly manufactured in British American Tobacco's Southampton factory, without added flavourings. Some versions, however, which are manufactured by operating companies overseas, are tailored to meet the taste preferences of local consumers. There are no ingredients or flavourings which are universally attractive to smokers, or which consistently enhance market success.

  221.  British American Tobacco, for more than 30 years, has used an internal panel of experts, supported where necessary by outside consultants, to advise on ingredients and their appropriate levels of use. The evaluation process includes: consideration of tobacco and food laws, for example, review of the UK list of permitted additives to tobacco, as well as the Flavour and Extract Manufacturers' Association ("FEMA") and/or Generally Recognised As Safe ("GRAS") lists in the United States; review of the published toxicology; consideration of the properties of the ingredients; and, where required, commissioning new research.

  222.  In the UK, the ISCSH issued guidelines for the testing and use of tobacco products containing additives, and in 1979 issued a list of permitted additives in tobacco products, which it continued to revise. The UK tobacco companies agreed to comply with these guidelines and to notify the DHSS of additives approved by the ISCSH for commercial use. It is quite clear that the ISCSH had in mind, when assessing additives, not only direct hazard potential, but the potential of ingredients to increase what they viewed as "dependence" (ISCSH, Second Report, paragraph 13, 1979).

  223.  British American Tobacco takes cognisance of the UK permitted additives list in reviewing ingredients for use worldwide, and has, of course, complied with local guidelines when placing products on the UK market.

ASH's Recent Criticisms

  224.  Despite the safeguards which have long been in place, and which have appeared satisfactory to independent experts (ISCSH, Fourth Report, paragraph 83, 1988), serious allegations have been made by ASH and others that manufacturers add ingredients to cigarettes with the intention of increasing their supposed "addictive" properties and to make them more attractive to children (ASH, Bates C, Jarvis M, Connolly G, "Tobacco Additives: Cigarette Engineering and Nicotine Addiction" (www.ash.org.uk/papers 1999)).

  225.  These allegations are irresponsible and unsupportable, and British American Tobacco welcomes this opportunity to correct the record. For reasons of length, it is not possible, in this memorandum, to deal with every misstatement made by ASH, but we intend to address two of the most egregious.

  226.  British American Tobacco does not use additives to increase the pharmacological effects of nicotine, and does not use additives for the purpose of making cigarettes more palatable to children.

  227.  The first allegation appears to be based on the supposed effects of the following additives: ammonia (and ammonium compounds); acetaldehyde; levulinic acid; cocoa (and theobromine); glycyrrhizin (from liquorice); and pyridine. We deal with these allegations briefly below. Detailed scientific presentations are currently being made to the Department of Health on these specific additives, along with other matters.

  228.  Ammonia: Ammonia compounds occur naturally in tobacco. Tobaccos contain natural ammonia compounds and sugars which react with one another during the curing and ageing process. Their reaction gives tobacco naturally pleasant aromas and flavours. A similar process occurs in beef, coffee and bread which produce unique aromas and flavours when they are roasted or baked. We add ammonia to some of our US-style cigarettes to enhance the reaction with sugars to further improve their flavour. Ammonia technology as such in commercial products does not increase "smoke pH", does not boost nicotine delivery to smokers and does not otherwise increase the smokers' absorption of nicotine.

  229.  It has long been known that the alkalinity of tobacco smoke will influence the proportion of nicotine present in its unprotanated ("free") as opposed to protonated ("bound") form. It is also known that adding substantial amounts of ammonia (or ammonium compounds) to tobacco, can increase the alkalinity (or "pH") of smoke. Ammonia is added to the tobacco blend in some cigarette brands during processing (typically through the addition of ammoniated reconstituted sheet). However, the levels of ammonia added in the manufacture of these commercial cigarettes are too low to have any material effect on smoke pH and thus do not alter the balance between the unprotonated and protonated levels of nicotine in mainstream smoke. This lack of a meaningful relationship between the amounts of ammonia in tobacco and yields of nicotine and ammonia in mainstream smoke or "smoke pH" of commercial products was demonstrated in a recent survey commissioned by the Massachusetts Department of Public Health (Rickert WS, "Partial Characterisation of 10 Common Brands of American Cigarettes", Labstat Incorporated Tobacco Characterisation Program, 1997).

  230.  Even if processing with ammonia did increase the availability of free nicotine, this would not lead to an increase in pharmacological effects in the central nervous system. It is simply false that free nicotine is transported to the brain faster than bound nicotine. Free nicotine will be readily absorbed in the mouth and upper respiratory tract, thus entering the venous circulation system instead of being transported to the alveoli in the periphery of the lung where it would enter the arterial circulation system. Simply put, nicotine absorbed in the venous circulation system would take a slower route to the brain than that taken by nicotine absorbed in the arterial circulation system. Moreover, whatever free nicotine did reach the alveolar region would be subject to the buffering capacity of the lining of the lung and would adopt the pH of the local biological environment. "Smoke pH" in commercial cigarettes is, therefore, unlikely to be affected by added ammonia and, if it were affected and caused an increase in free versus bound nicotine, this at most would likely increase sensory effects in peripheral nerves and reduce effects in the central nervous system because of the altered site of absorption. But, in any event, once nicotine, regardless of its form in smoke, enters the blood stream it adopts to the pH of blood, rendering the original "smoke pH" largely irrelevant.

  231.  It has also been alleged by ASH in its report on tobacco additives that the tobacco companies have exploited free nicotine to enable them to "cheat" the machine measurements of tar and nicotine levels. The implication is that increasing the "pH" of cigarette smoke results in an increase in the amounts of nicotine in the vapour phase and that this would have the effect of evading detection in the standard machine method. However, experimental studies have demonstrated that this claim is false as over 99.9 per cent of nicotine delivered from a cigarette is collected on the Cambridge filter pad in the standard ISO method, irrespective of "smoke pH" or cigarette design changes (Davis DL and Nielsen MT, "Tobacco Production, Chemistry and Technology", Blackwell Science, 1999).

  232.  Finally, ammonia is not used to increase nicotine transfer. This allegation seems to be based on an old British American Tobacco report, in which vast quantities of ammonia were added to experimental cigarettes in order to conduct fundamental research on the relationship between alkalinity and sensory properties, such as "impact". The amounts of ammonia used in the experiment were such as practically to ferment the tobacco, and bear no relation to anything done in our commercial products.

  233.  Acetaldehyde and levulinic acid: ASH stated in its report that ingredients such as acetaldehyde and levulinic acid have pharmacological effects in controlling nicotine absorption levels and/or delivery. ASH alleges that scientists within the tobacco companies suspected that acetaldehyde could enhance the addictive effects of nicotine. ASH also alleges that levulinic acid was used by the tobacco companies to increase the impact of nicotine and to maintain a low tar/nicotine ratio on smoking machine measurements. There appears to be no basis for making these allegations. We do not propose, however, to comment on them any further in this memorandum as the allegations refer to documents relating to the activities of other companies.

  234.  Cocoa (which contains theobromine): It is alleged that the 1 per cent or so theobromine contained in cocoa may have a bronchodilation effect, expanding the airways and facilitating increased smoke and nicotine intake (ibid, p 14). This is based on a misrepresentation of a study in which subjects were administered, not a 10 mg dose of theobromine, as ASH claims, but a 10 mg per kg body weight dose. We do not believe that there is a bronchodilation effect at the levels at which cocoa is used in commercial cigarettes.

  235.  Bronchodilation would not influence nicotine intake or uptake for the following reasons:

    —  Changes in inhalation depth have a significant influence on airway calibre. Increasing the depth of inhalation produces an increase in airway calibre (ie bronchodilation). This physiological phenomenon has been known for decades.

    —  If a dilation of the airways were to enhance nicotine absorption and uptake one would expect to observe a relationship between inhalation depth and the amounts of nicotine absorbed into the blood. This was studied by Zacny et al (Journal of Pharmacology and Experimental Therapeutics, 240 (2), p 554, 1987) and they demonstrated that increasing inhalation from 10 per cent to 60 per cent vital capacity did not influence the amounts of nicotine absorbed into the blood. Increasing breath-hold duration from zero to 16 seconds had no effect on nicotine absorption. By contrast, increasing puff volume from 15 ml to 60 ml (at constant inhalation depth and breath-hold) produced a linear increase in nicotine absorption.

    —  The majority of nicotine generated from the cigarette is retained and absorbed during a "normal" inhalation. This is the case for Virginia style products which do not use casing containing cocoa. Davis et al showed that virtually 100 per cent of the nicotine delivered from such a cigarette was retained within the respiratory system during a normal inhalation. Thus there is little scope for increasing lung nicotine retention by any cigarette design feature.

  236.  Liquorice (which contains glycyrrhizin): The only citation given by ASH to support the contention that glycyrrhizin acts as a bronchodilator is testimony by Dr Farone at a public hearing on proposed regulation within the Massachusetts Tobacco Control Programme in June 1997. In his testimony, Dr Farone claims to rely on a 19th century textbook, which, in any case, does not describe glycyrrhizin as a bronchodilator. We are not aware of any evidence to support this assertion. There is even a lack of evidence that glycyrrhizic acid, found in liquorice, transfers to smoke, although one breakdown product, glycyrrhetinic acid, is found at trace levels.

  237.  Pyridine: Again, allegations that pyridine increase the effects on the central nervous system seem to be based on Dr Farone's testimony and the same 19th century textbook. ASH also makes selective quotations from a report prepared for British American Tobacco on the pharmacological effects of pyridine. While ASH acknowledges that the report states that the levels of pyridine formed in smoke are unlikely to be high enough to be pharmacologically active, ASH fails to make it clear just how remote the possibility of such an effect is, as illustrated by the following passages from the same report:

  238.  Additives and children: ASH's other allegation is that British American Tobacco and other tobacco companies use additives to make cigarettes more palatable to children. Ingredients are indeed used to make cigarettes more palatable, and to reduce harshness and irritation. The ASH report suggests, however, that liquorice, cocoa and other substances are used to create sweet-tasting products with particular appeal to children. This is false. Casings, which can incorporate substances such as liquorice and cocoa, are used primarily in the processing of Burley tobaccos to replace sugars lost during air-curing and to relieve the harshness of the smoke. These casings do not impart liquorice or cocoa flavours which are identifiable as such by the smoker. Although a cigarette containing liquorice and cocoa casings does not have a taste character similar to that produced by eating liquorice or cocoa products, they do act as flavour modifiers, and panellists can be trained to recognise taste characters produced by these casings. Critics would doubtless allege that merely seeking to reduce the bitterness of smoke is a strategy to appeal to children. It should be pointed out, however, that Virginia-style cigarettes, which predominate in the UK and some other markets, make little or no use of casings. As far as we are aware, such cigarettes are not more or less palatable to children than US-style cigarettes. It is also worth observing that the problem of children smoking is similar in the US to the UK, despite the different use of additives in each country.

  239.  British American Tobacco believes that the Government should base consumer protection policy in relation to cigarette ingredients on informed discussions with the tobacco manufacturers and on objective scientific appraisal, not on inflammatory and misleading pieces of advocacy.


 
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Prepared 28 February 2000