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Coffee, tea, and maté
752
Coffee, tea, and maté
Caffeine-containing beverages have been consumed world wide for centuries. Coffee is said to have arrived on the Arabian peninsula from Ethiopia in 575 AD, and tea (first referenced in a Chinese dictionary in 350 AD) was first used as a medicine. Huge quantities are consumed: for example, annual global consumption of green coffee (principally Coffea arabica and C canephora) is about 5 million tonnes a year. Various studies have cast doubt on the safety of caffeine-containing beverages, some of which have now come under the scrutiny of the International Agency for Research on Cancer (IARC). The latest volume of IARC monographs on the evaluation of carcinogenic risks to manl centres mainly on three popular beverages-tea, coffee, and mate. Risk evaluation is complicated, because the drinks contain many hundreds of compounds apart from caffeine. Roasted coffee, for instance, contains more than 700 volatile and numerous non-volatile compounds (eg, non-caffeine purines, chlorogenic acids, melanoidins). Moreover, beans and leaves are processed for consumption in various ways and are then prepared according to local custom before drinking. Thus, coffee can be boiled, infused, filtered, percolated, vapourised under pressure, or reconstituted from a dried ("instant") extract; and black, green, and Oolong teas are produced by different manufacturing processes of tea flush (the harvested new growth of the tea bush, Camellia sinensis). Individual consumption of beverages is difficult to quantify because there is no standardised measure for a cup. A further complicating factor is that the drinking of these beverages is associated with characteristic behaviours (eg, cigarette smoking) and dietary habits, which may vary
A
regionally. critical
of numerous experimental and studies leads the IARC working group to conclude epidemiological that coffee might be carcinogenic to the human urinary bladder but might actually protect against cancer of the colon and rectum. Breast cancer risk is found to have no association with coffee drinking. For tea, the available data are judged to be inadequate to demonstrate a carcinogenic risk, though there is some evidence that drinking very hot tea increases the risk of oesophageal cancer. Further evidence that the temperature of the beverage rather than the drink itself is important comes from the data on mate drinking. Mate is prepared from the leaves of Ilex paraguarensis and is consumed in South America as a piping hot drink (after repeated addition of almost boiling water to the infusion); but it is also drunk, cold, in Germany. Drinking hot mate is judged to have a probable association with the development of oesophageal and oral cancers. In addition to caffeine the working group also considers three other common constituents of these beverages-namely, theophylline, theobromine, and methylglyoxyl-but fmds the evidence inadequate for assessment of carcinogenic risk. assessment
1. Intemanonal Agency for Research on Cancer. IARC monographs on the evaluation of carcinogenic risks to humans. Vol 51. Coffee, tea, mate, and methylxanthines and methylglyoxal. Lyon: IARC. 1991. Pp 513. US$72.00 ISBN 9283212517.
Salmeterol study criticised The current issue of the Drug and Therapeutics Bulletin raises questions about Glaxo’s ’Serevent’ national surveillance study, which is enrolling 24 000 patients. The patients are receiving either salmeterol twice daily or salbutamol four times daily for 4 months. The aim of this large controlled trial is to collect safety data, though the patients have not been told this. The entry criteria specify that patients should clinically require regular bronchodilator therapy. Such patients, however, according to the recommendations of the British Thoracic Society, should be treated with an inhaled corticosteroid. The trial protocol does not consider this adequately: any patients who need but are not using inhaled corticosteroid on entry are unlikely to get it. The trial protocol was approved by the ethics committee of the Royal College of General Practitioners at about the time the BTS guidelines were published, so that these were not considered when the proposal was discussed. The DTB has raised this as an issue of ethics and has suggested that Glaxo should amend the protocol to ensure that all patients who need inhaled steroid are given it, and that GPs should be advised to consider the BTS guidelines in treating patients who have left the
study. Glaxo disagree, saying that any change would delay the trial, which would displease the Medicines Control Agency as well as the company.
The ethics committee of the RCGP has considered the point made by D TB and agrees that ethics committees need a mechanism for reconsidering projects after approving them, if changed circumstances outside the trial itself make this desirable. The prime responsibility for such reconsideration, however, remains with the sponsor.
Withdrawal of ’Micturin’ a treatment for urinary has been world wide withdrawn incontinence, following reports of 36 cases of torsades de pointes ventricular fibrillation associated with use of the drug. 14 cases of bradyarrhythmia and 8 deaths have also been reported. Most cases have originated in the UK. Kabi Pharmacia, the manufacturer of micturin, advises doctors to terminate treatment as soon as practicable and asks them to bear in mind the long elimination half-life of terodiline when considering alternative therapy.
’Micturin’
(terodiline hydrochloride),
Oslerian provenance Canadian by birth and later to become Regius professor of at the University of Oxford, Sir Willian Osler’s (18491919) reputation as a clinician spanned two continents. Now his name is synonymous with careful clinical method and a scholarly and humanistic approach to medicine. Dr Alex Sakula—a selfconfessed propagator of the Oslerian message-has written an affectionate and engaging account of the known portraits of a man who also held chairs at McGill, Pennsylvania, and Johns Hopkins Universities.’ A collection of busts, plaques, medallions, medals, and even stamps are included for the Osler enthusiast. medicine
portraiture of Sir William Osler. London: Royal Society of Medicine. 1991. Pp 91 £15. ISBN 185315153X. Copies are available from the Royal Society of Medicine Services Ltd, 1 Wimpole Street, London W1M 8AE, UK.
1 Sakula A. The
In
England
Now
It’s a long time since I last reported on the vicissitudes besetting my efforts to learn to swim. I won’t bore you with the details, suffice it to say I can now manage 25 metre lengths of our local pool-but only because it is a uniform 1-2 metres deep-nothing would persuade me out of my depth. Still, I am quietly pleased with
myself. I have realised for a long time that swimming is a valuable, healthy exercise, and it certainly is good for ageing joints, but now I have discovered that swimming is just as beneficial socially and emotionally. At our sessions the amount of chattering that goes on
be believed; the men are as bad as the women. I am of the regulars never manage a full length in the course of spending most of their time chatting at one end or the
must be heard to sure some an
hour,
other. Not that it is idle chatter, far from it. Serious medical matters are mooted. Long discussions over the advisability-or otherwise--of elective surgical procedures are common. The group is supportive of its members: it has just welcomed a newly bereaved man into its midst, for example, and he can be seen talking through his loss with various of our members, many of them widowed themselves. Tears are not noticed on faces wet from swimming. I suppose it is something about the warm relaxing ambience of the pool that leads to easy confidences. Also there is total social levelling; social signs and class barriers disappear when people are clad in swimsuits and are only visible from about the third intercostal space upwards. Here is an interesting speculation: I know there is a vogue for childbirth in water, but perhaps other specialties ought to consider the possibilities. In particular, psychotherapy seems ideally suited to the relaxing atmosphere of a pool. Indeed, therapy is undoubtedly taking place daily at our pool, and none the worse for being carried out by ordinary, caring people. I reckon it is far more effective than attendance at a psychiatric outpatients. And as a psychiatrist, I can say that.
Coffee, tea, and maté
Caffeine-containing beverages have been consumed world wide for centuries. Coffee is said to have arrived on the Arabian peninsula from Ethiopia in 575 AD, and tea (first referenced in a Chinese dictionary in 350 AD) was first used as a medicine. Huge quantities are consumed: for example, annual global consumption of green coffee (principally Coffea arabica and C canephora) is about 5 million tonnes a year. Various studies have cast doubt on the safety of caffeine-containing beverages, some of which have now come under the scrutiny of the International Agency for Research on Cancer (IARC). The latest volume of IARC monographs on the evaluation of carcinogenic risks to manl centres mainly on three popular beverages-tea, coffee, and mate. Risk evaluation is complicated, because the drinks contain many hundreds of compounds apart from caffeine. Roasted coffee, for instance, contains more than 700 volatile and numerous non-volatile compounds (eg, non-caffeine purines, chlorogenic acids, melanoidins). Moreover, beans and leaves are processed for consumption in various ways and are then prepared according to local custom before drinking. Thus, coffee can be boiled, infused, filtered, percolated, vapourised under pressure, or reconstituted from a dried ("instant") extract; and black, green, and Oolong teas are produced by different manufacturing processes of tea flush (the harvested new growth of the tea bush, Camellia sinensis). Individual consumption of beverages is difficult to quantify because there is no standardised measure for a cup. A further complicating factor is that the drinking of these beverages is associated with characteristic behaviours (eg, cigarette smoking) and dietary habits, which may vary
A
regionally. critical
of numerous experimental and studies leads the IARC working group to conclude epidemiological that coffee might be carcinogenic to the human urinary bladder but might actually protect against cancer of the colon and rectum. Breast cancer risk is found to have no association with coffee drinking. For tea, the available data are judged to be inadequate to demonstrate a carcinogenic risk, though there is some evidence that drinking very hot tea increases the risk of oesophageal cancer. Further evidence that the temperature of the beverage rather than the drink itself is important comes from the data on mate drinking. Mate is prepared from the leaves of Ilex paraguarensis and is consumed in South America as a piping hot drink (after repeated addition of almost boiling water to the infusion); but it is also drunk, cold, in Germany. Drinking hot mate is judged to have a probable association with the development of oesophageal and oral cancers. In addition to caffeine the working group also considers three other common constituents of these beverages-namely, theophylline, theobromine, and methylglyoxyl-but fmds the evidence inadequate for assessment of carcinogenic risk. assessment
1. Intemanonal Agency for Research on Cancer. IARC monographs on the evaluation of carcinogenic risks to humans. Vol 51. Coffee, tea, mate, and methylxanthines and methylglyoxal. Lyon: IARC. 1991. Pp 513. US$72.00 ISBN 9283212517.
Salmeterol study criticised The current issue of the Drug and Therapeutics Bulletin raises questions about Glaxo’s ’Serevent’ national surveillance study, which is enrolling 24 000 patients. The patients are receiving either salmeterol twice daily or salbutamol four times daily for 4 months. The aim of this large controlled trial is to collect safety data, though the patients have not been told this. The entry criteria specify that patients should clinically require regular bronchodilator therapy. Such patients, however, according to the recommendations of the British Thoracic Society, should be treated with an inhaled corticosteroid. The trial protocol does not consider this adequately: any patients who need but are not using inhaled corticosteroid on entry are unlikely to get it. The trial protocol was approved by the ethics committee of the Royal College of General Practitioners at about the time the BTS guidelines were published, so that these were not considered when the proposal was discussed. The DTB has raised this as an issue of ethics and has suggested that Glaxo should amend the protocol to ensure that all patients who need inhaled steroid are given it, and that GPs should be advised to consider the BTS guidelines in treating patients who have left the
study. Glaxo disagree, saying that any change would delay the trial, which would displease the Medicines Control Agency as well as the company.
The ethics committee of the RCGP has considered the point made by D TB and agrees that ethics committees need a mechanism for reconsidering projects after approving them, if changed circumstances outside the trial itself make this desirable. The prime responsibility for such reconsideration, however, remains with the sponsor.
Withdrawal of ’Micturin’ a treatment for urinary has been world wide withdrawn incontinence, following reports of 36 cases of torsades de pointes ventricular fibrillation associated with use of the drug. 14 cases of bradyarrhythmia and 8 deaths have also been reported. Most cases have originated in the UK. Kabi Pharmacia, the manufacturer of micturin, advises doctors to terminate treatment as soon as practicable and asks them to bear in mind the long elimination half-life of terodiline when considering alternative therapy.
’Micturin’
(terodiline hydrochloride),
Oslerian provenance Canadian by birth and later to become Regius professor of at the University of Oxford, Sir Willian Osler’s (18491919) reputation as a clinician spanned two continents. Now his name is synonymous with careful clinical method and a scholarly and humanistic approach to medicine. Dr Alex Sakula—a selfconfessed propagator of the Oslerian message-has written an affectionate and engaging account of the known portraits of a man who also held chairs at McGill, Pennsylvania, and Johns Hopkins Universities.’ A collection of busts, plaques, medallions, medals, and even stamps are included for the Osler enthusiast. medicine
portraiture of Sir William Osler. London: Royal Society of Medicine. 1991. Pp 91 £15. ISBN 185315153X. Copies are available from the Royal Society of Medicine Services Ltd, 1 Wimpole Street, London W1M 8AE, UK.
1 Sakula A. The
In
England
Now
It’s a long time since I last reported on the vicissitudes besetting my efforts to learn to swim. I won’t bore you with the details, suffice it to say I can now manage 25 metre lengths of our local pool-but only because it is a uniform 1-2 metres deep-nothing would persuade me out of my depth. Still, I am quietly pleased with
myself. I have realised for a long time that swimming is a valuable, healthy exercise, and it certainly is good for ageing joints, but now I have discovered that swimming is just as beneficial socially and emotionally. At our sessions the amount of chattering that goes on
be believed; the men are as bad as the women. I am of the regulars never manage a full length in the course of spending most of their time chatting at one end or the
must be heard to sure some an
hour,
other. Not that it is idle chatter, far from it. Serious medical matters are mooted. Long discussions over the advisability-or otherwise--of elective surgical procedures are common. The group is supportive of its members: it has just welcomed a newly bereaved man into its midst, for example, and he can be seen talking through his loss with various of our members, many of them widowed themselves. Tears are not noticed on faces wet from swimming. I suppose it is something about the warm relaxing ambience of the pool that leads to easy confidences. Also there is total social levelling; social signs and class barriers disappear when people are clad in swimsuits and are only visible from about the third intercostal space upwards. Here is an interesting speculation: I know there is a vogue for childbirth in water, but perhaps other specialties ought to consider the possibilities. In particular, psychotherapy seems ideally suited to the relaxing atmosphere of a pool. Indeed, therapy is undoubtedly taking place daily at our pool, and none the worse for being carried out by ordinary, caring people. I reckon it is far more effective than attendance at a psychiatric outpatients. And as a psychiatrist, I can say that.