Rapid Responses to:
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Rapid Responses: Rapid Responses published:
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Black Coffee is equally dangerous
- Brian Grove (28 March 2009)
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Sri Lanka (Ceylon) - Major tea exporter to Iran
- Visahan Y Sabaratnam (30 March 2009)
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Why northern Iran?
- Reza Aghamohammadzadeh (31 March 2009)
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Drinking hot tea and cytoprotection
- Richard G Fiddian-Green (31 March 2009)
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The devil is in the detail
- Roger K.A. Allen (2 April 2009)
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Indeed hot tea may have a role in esophageal cancer!
- Shad S Akhtar (3 April 2009)
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Initiation or promotion?
- Richard G Fiddian-Green (3 April 2009)
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The Problem is in the METHOD the Iranians brew their tea
- Kirsten H. Kristensen (4 April 2009)
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Scientific criticism is not your journalists' cup of tea
- Roger K.A. Allen (5 April 2009)
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Critical Appraisal - Was it a cohort study or a Cross-sectional survey ?
- Raheem Hassanali Dhanani, Richard Bamuhimbisa (6 April 2009)
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tea itself without hot drinking is not innocent in esophgeal cancer
- mohammad saeed shakari (7 April 2009)
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And what about opium chewing?
- Ralph Lucas (7 April 2009)
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more information needed
- Mostafa A. Elnaggar (9 April 2009)
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British Standard
- Charlotte A Davies (10 April 2009)
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Isn't green tea hotter?
- s chan (10 April 2009)
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The ups and downs of drinking tea
- John EA Somner, Kirsten M. Scott (19 April 2009)
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Oesophageal squamous cell carcinoma:Thermal effect and possible prevention
- Biji T. Kurien, Yaser Dorri, Rachna Aggarwal, Anil D'souza, R. Hal Scofield (29 April 2009)
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Hot beverages and risk of oesophageal cancer.
- Aline Marcadenti, Erlon O. de Abreu-Silva, MD (29 April 2009)
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Re: The Problem is in the METHOD the Iranians brew their tea
- Yaser Dorri (1 May 2009)
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Hot tea and oesophageal cancer
- Belinda Stanley (7 May 2009)
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The temperature is the keyword and the optimum temperature is given by the temperature of human milk
- Dr Viera Scheibner PhD (7 May 2009)
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Not the tea but helicobacter pylori infection always irritates me!
- Nazan Karaoglu (9 May 2009)
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Hot Tea Drinking and Hookah Smoking in Iran
- Kamal Chaouachi (9 October 2009)
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Brian Grove, Owner of animal refuge Escobar 1625, Buenos Aires, Argentina
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I live in Latin America and the emphasis of the study on the word "tea" misses something very important. In Latin countries the majority of people drink black coffee, just as hot and potentially just as dangerous in terms of cancer risk. In Argentina, of course, traditionally as well as coffee, they drink Maté - which is never drunk with milk and is frequently scaldingly hot. Without at least a mention of the fact that other hot drinks could be just as dangerous, the media in these countries will (and have) ignored the report or if they report it at all, ONLY mention tea so that most ordinary readers won't get the vital message that drinking very hot liquids of any kind can be dangerous. Competing interests: None declared |
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Visahan Y Sabaratnam, Consultant general surgeon, Sri Lanka. Teaching Hospital Batticoloa, Sri Lanka.
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Sri Lanka, Ceylon, is the main exporter of tea to Iran. We in Sri Lanka, consume black tea mainly. Everybody in Sri Lanka drinks tea, most drink black tea. But dietery habits are fast changing, younger generations tend to drink fizzy bottled imported drinks, they are cheaper and safer with regard to hygeine. Due to rise in price of milk, people who drank milk tea are avoiding milk. But, oesophageal cancer is rare in Sri Lanka. Flexible oesophago gastro duodenoscopy is a investigation, which is freely available and commonly performed. The team has put lot of effort and time into this study. A very good study. But I have the following questions. 1- Is there a safer alternative to tea. 2- What is the impact of this study. Will the population incline toward fizzy drinks, will they drink coffee? 3- What is the advice you are going to give the population. (Quantity of tea, temprature and milk) 4-Have you looked into the water, minerals etc in the region. In what do they drink tea,glass or cup. What is the other habits of black tea drinkers. In Sri Lanka many black tea drinkers smoke others add ginger to tea. I have noticed wide publicity being given to this article by media. A very good study, but the public should not be mislead. Competing interests: None declared |
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Reza Aghamohammadzadeh, Core Medical Trainee Manchestrer, UK
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This is indeed a very interesting article with potentially huge public health implications. The authors state that ‘an ecological study showed that inhabitants of Golestan drank more tea and at a higher temperature than people living in a nearby area with a low incidence of oesophageal cancer’. I wonder how the tea-drinking habits of the inhabitants of Golestan compares to that of Iran’s other provinces on a more national scale. I note that the research team have used interviews to complete validated questionnaires and wonder how accurate and honest the response to the alcohol consumption would be in an Islamic Republic where Alcohol is officially prohibited. I do appreciate that the study has controls with the specific variables relating to tea-drinking habits, but I wonder if the rates of alcohol consumption in Golestan are actually higher than anywhere else in the country as the province’s proximity to other Caspian sea nations means that alcohol may be more readily available in this region for consumtion in private. Could this mean that there are other areas of Iran with similar tea-drinking habits with lower oesophageal cancer rates because of lower confounding factors such as alcohol. Competing interests: None declared |
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Richard G Fiddian-Green, FRCS, FACS None
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That drinking hot tea should be associated with an increased risk of developing oesophageal cancer (1) is most interesting. As the pH falls linearly as the temperature rises (2) drinking hot tea is almost certainly associated with a fall in interstitial pH certainly in the most superficial layer of the statified squamous epithelium lining the oesophagus. The primary mechanism protecting the oesophagus is likely to be peristalsis. If one assumes that the temperature in the cells transiently equilibrate with that in warm (60 degrees C), hot (65 degrees) and very hot (70 degrees) tea the pH will fall to 7.06, 6.95, and 6.87 respectively. If, however, the temperature of the warm tea diffuses into blood fast enough to maintain the pH at 7.40 the pH in hot and very hot tea might only fall to 7.29 and 7.21 respectively. A fall below 7.32 in the stomach is sufficient to impair cellular function (3). That impairment might include mechanisms that protect cells from becoming malignat. A fall below pH 6.86 in the colon sifficient to be associated with visible evidence of haemorrhagic necrosis (4). The dysfunction is important for, as Andre Robert first showed, "pretreatment with prostaglandins in nonantisecretory doses protected both the stomach and intestine against a wide variety of injurious agents of diverse chemical structure... In the stomach these prostanoids have been shown to prevent gastric erosions and ulcers induced by several damaging strategies, including restraint and cold stress, pyloric ligation, steroid administration, and luminal exposure to bile salts, serotonin, reserpine, boiling water, absolute ethanol, concentrated acid, concentrated base, or various drugs such as nonsteroidal anti-inflammatory compounds.... This cytoprotective action of prostaglandins has also been demonstrated to occur in the small bowel and colon..Microtubule organization and stability play important roles in preventing cell injury by ethanol and may be essential to the mechanism of prostaglandin-induced cytoprotection" (5). But prostaglandins are produced endogenously in response to stressful stimuli, such as haemorrhage (6) and a fall in tissue pH is likely to impair synthesis. Blood flow is clearly an important means of protecting cells from thermal injury, that in the stomach being far greater than the oesophagus which rarely bleeds when one removes it bluntly or even extracts it with a varicose vein stripper. Any impairment in oesophageal blood flow can, therefore, be expected to increase the likelihood of hot tea causing a tissue acidosis. 1. Farhad Islami, Akram Pourshams, Dariush Nasrollahzadeh, Farin Kamangar, Saman Fahimi, Ramin Shakeri, Behnoush Abedi-Ardekani, Shahin Merat, Homayoon Vahedi, Shahryar Semnani, Christian C Abnet, Paul Brennan, Henrik Møller, Farrokh Saidi, Sanford M Dawsey, Reza Malekzadeh, and Paolo Boffetta. Tea drinking habits and oesophageal cancer in a high risk area in northern Iran: population based case-control study BMJ 2009; 338: b929 2. JOHN W. SEVERINGHAUS, POUL ASTRUP, and JOHN F. MURRAY Blood Gas Analysis and Critical Care Medicine Am. J. Respir. Crit. Care Med., Volume 157, Number 4, April 1998, S114-S122 3. Low intramucosal pH is associated with failure to acidify the gastric lumen in response to pentagastrin. Higgins D, Mythen MG, Webb AR. Intensive Care Med. 1994;20(2):105-8. 4. Sigmoid intramural pH for prediction of ischemic colitis during aortic surgery. A comparison with risk factors and inferior mesenteric artery stump pressures. Schiedler MG, Cutler BS, Fiddian-Green RG. Arch Surg. 1987 Aug;122(8):881-6. 5. A. Banan, G. S. Smith, C. L. Rieckenberg, E. R. Kokoska, and T. A. Miller Protection against ethanol injury by prostaglandin in a human intestinal cell line: role of microtubules Am J Physiol Gastrointest Liver Physiol 274: G111-G121, 1998. 6. Increased ex vivo synthesis of prostaglandin E2 by gastric tissue after hemorrhage in rats. Fink MP, Caveda EO, Gardiner WM, Fiddian-Green RG. Am J Surg. 1987 Jan;153(1):139-43.; Competing interests: None declared |
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Roger K.A. Allen, Senior Thoracic and Sleep Physician Wesley Medical Centre, Auchenflower, Brisbane, Qld 4066, Australia
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As I quickly sip a cup of tea between patients, I wonder why more doctors who have hot drinks on the run, don't develop oesophageal cancer if the above study is correct. The authors seem to skip over how the tea is made, in what metal is the water brewed, with what fuel, what the tea is kept in and in what receptacle the tea is brewed eg a metal tea-pot made of what? Have they controlled for water content eg strontium etc., the type of pot etc., type of tea and whether it contains things like toxins,fungal elements etc.. Our kettles at home quickly get a residue of boiler scale due to hard water. There are lots of minerals in water, perhaps dioxins or nuclear fallout from secret Iranian tests ;) etc. Are they using heavy water and contaminated tea leaves eg with pesticides etc? I remain a sceptic about the hot water. I'd better get back to my milk tea at 60 degrees Celsius made of heavy water with added strontium. As an aside, in Australia there is a potential health risk from hot tea when the more macho Australian male/bushie viz. bushmen make billy tea by swinging the boiling brew around their head in a circle like a centrifuge to make the tea leaves settle. If you hit your leg with the billy (viz. billy can) it can be messy. Competing interests: I enjoy good Ceylon tea (preferably Dilmah), strong with a little milk and no sugar; milk in last. I have as yet received no commission from Dilmah. |
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Shad S Akhtar, Consultant Medical Oncologist Srinagar, Indian Kashmit, 190008
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It is very interesting to note the association between hot tea and esophageal cancer. For years we have been looking at the high incidence of esophageal cancer in Kashmir, where it is probably the commonest cancer seen (there is no population based registry in Kashmir as yet). A major constituent of traditional Kashmiri diet is the salt tea, brewed over hours in copper utensils. However, what is more relevant, it is served in samovars where the tea is kept boiling by feeding the central chute with burning charcoal. It is poured into large cups, steaming, an adult consumes 2-4 cups on an average. Of course, the tea is consumed as hot as it can be. It will be interesting to look into the temperature of the tea consumed and risk of esophageal cancer in Kashmiri population too. Competing interests: None declared |
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Richard G Fiddian-Green, FRCS, FACS None
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There are two factors involved in carcinogenesis, initiation and promotion as we learned from the studies with benzpyrene in our pathology. Temperature might be a promoting rather than the initiating factor as proposed (1) for the oesophageal cancers developing in the Xhosa in the Transkei, now Eastern Cape, where I was brought up. The incidence in the rural Xhosa is as high as any in the world and commonly accompanied by tuberculosis. 1. Carcinogens and endemic squamous cancer of the oesophagus in Transkei, South Africa. Environmental initiation is the dominant factor; tobacco or other carcinogens of low potency or concentration are sufficient for carcinogenesis in the predisposed mucosa Medical Hypotheses, Volume 69, Issue 1, Pages 125-131 A. Sammon Competing interests: None declared |
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Kirsten H. Kristensen, Tea Coach and Certified Tea Specialist Tea 4 U, LLC, Ocean, NJ 07712
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As a tea specialists promoting the health benefits of tea drinking I have been having an inner discussion with myself overnight and this morning got the revelation: THE PROBLEM IS IN THE WAY THE IRANIANS BREW THEIR TEA! As can be seen on the video posted with the online study (and which I know from my good Iranian friends in NJ) it is an Iranian culture to brew their tea in samovars. So each morning they brew a concentrate of black tea which is kept warm on the top of the samovar. The samovar itself keeps contantly boiling water, ready for a cuppa anytime (and often). What the Iranians do, is pour a little bit of the concentrate in their small glass cups (glass holds the heat longer than china/ceramic cups) and add boiling water from the samovar - and gulp it right away! This is why the cup of tea is 'very hot' (the definition in the study). When we brew black tea in the Western world, we (the tea enthusiasts) use whole leaf tea either directly in a teapot (British method) or in an infuser inserted into the teapot. When the water boils, we pour it over the tea leaves and let it steep for ~5 min. Then take up the leaves, pour the tea in a (cold) cup and sip it (not gulp right away as the Iranians have a habit of doing). The water we use has already been away from the stove for 5 min before we (slowly) drink it. This is the big cultural difference, and the Westerners should not worry about esophageal cancer as long as we steep our tea that way. My revelation came this morning when I had my first cup and tried to compare it to the tea I get when I visit my Iranian friends. I never liked tea at their home (even when they buy the tea from my company!) The concentrate - simmering while waiting to be used does something to the tea taste (and antioxidants?) and adding boiling water to the concentrate may change the way tea tastes as well. The tea leaves were not 'woken up' by freshly boiled water and set to steep properly and then enjoyed. (I now remember the scolding feeling on my tongue when drinking the Iranian cardamom tea. Not my cup of tea - and not for my health either!) (PS. The Iranian cardamom tea tastes wonderful, when steeped the Western way!) The Iranians will need to learn from the Western world how healthy tea is made. So don't worry - if you make your tea the Western way - and drink your recommended 4 cups a day! Competing interests: Tea Specialist, wanting the world to continue drinking tea for their health and pleasure |
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Roger K.A. Allen, Senior Thoracic and Sleep Physician Wesley Medical Centre, Auchenflower, Brisbane, Qld 4066, Australia
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Just as I suspected. The above comments about how the tea was brewed etc. by at least two authors on Rapid Responses show that there are many variables in this story which need investigation. However it also highlights medical journalists' uncritical reporting and disseminating of this story which has bounced around the globe like an out of control pogo stick. The lay public alas are still naive enough to regard what appears in medical press as true when you and we all know that most papers and studies sooner or later end up being either untrue, unfounded, misleading, half true etc. Editors and publishers also have a vested interest in "spin" or a "beat up" on articles, with their own tiresome press releases, etc. I have seen this with journals in Australia. Not a word can be said until the big day when the ink dries. Most such articles metamorphose in the lay press, radio, TV (usually a seven second grab), and to be regurgitated by a journalist (also lay) with no idea of scientific method or statistical analysis. We are lucky to have one excellent journalist with a scientific background, Robin Williams who reports medical articles on our ABC radio's science show but apart from him we have a journalistic desert. In my opinion, when the BMJ reports these stories and has a blog dedicated to such, there is an obligation to debunk, "de-bovrilise", nay even lampoon papers for without such we have a journal which disseminates "facts" which may be harmful or quite alarming to the public and even industry eg do we drink tea any more? Finally, the number of papers with negative findings and in particular, findings which refute previous papers is low in the world literature and many are rejected because their finding is "nul". I has happened to me when we repeated study which we had published in the Lancet and which was much more sound. Journals are not good at publishing what is not "sexy" as we all want a good story even if it is rubbish. To offset this we have Rapid Responses, an enlightened medium which is sadly missing in the Australian medical press. Alas, the majority of the lay public and certainly educated journalists (an oxymoron or a tortology?) do not read. Satire and lampooning has long been a British journalistic tradition which is sadly lacking in humourless, po-faced medical journals. It is in need of a rebirth. It may even make reading medical journals fun. But perhaps it is not the journal's cup of tea. Competing interests: None declared |
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Raheem Hassanali Dhanani, Chairman, Department of Family Medicine Aga Khan University, Eastern Africa, Richard Bamuhimbisa
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While reviewing the article with a group of Family Medicine Residents, it came across that whether the second part of the study should be labelled as a Cohort Study or could it have been lablled as a Cross Sectional study? As per the litearture, Cohort studies look at certain outcome/s in light of the risk factors. Here in this study, what outcome was being looked at? In our opinion, it could have been labelled as a cross-sectional survey. Secondly, many factors have been pointed out by our colleagues in their separate rapid responses which have not been looked into. In addition, 15% of all Oesophageal cancers analysed worldwide with polymerise chain reaction have been positive for HPV DNA. The detection rate is much higher in high risk areas such as China and Iran (1). Furthermore, family history, occupational history (exposure to trichlorethylene in the dry-cleaning industry and silica dust may increase risk, though this is likely to account for only a very small number of cases) (2)(3) and certain rare conditions such as Tylosis, an autosomal dominant inherited condition associated with palmoplantar keratosis (thickening of the skin on the palms of the hands and soles of the feet) have been linked with an increased risk of Squamous Cell Carcinoma of Oesophagus. 1. Chang, F., et al., Human papillomavirus involvement in esophageal carcinogenesis in the high-incidence area of China. A study of 700 cases by screening and type-specific in situ hybridization. Scand J Gastroenterol, 2000. 35(2): p. 123-30. 2. Raaschou-Nielsen, O., et al., Cancer risk among workers at Danish companies using trichloroethylene: a cohort study. Am J Epidemiol, 2003. 158(12): p. 1182-92. Yu, I.T., et al., Further evidence for a link between silica dust and esophageal cancer. Int J Cancer, 2005. 114(3): p. 479-83. 3. Ribeiro, U., Jr., et al., Risk factors for squamous cell carcinoma of the oesophagus. Br J Surg, 1996. 83(9): p. 1174-85. Competing interests: None declared |
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mohammad saeed shakari, medical student of tehran university of medical science 12345
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tea and other xantin containing drinks are responsible for GERD (gastroesophageal reflux disease), because xantin as well as smoking and fat containing foods cause relaxation of inferior esophageal sphincter (xantin inhibits phosphodiesterase which is responsible for CAMP degradation). on the other hand, GERD is a chief cause of esophageal cancer. in Golestan, Iran, tea is a popular drink so the relation between tea drinking without its hot drinking must be evaluated first. Competing interests: None declared |
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Ralph Lucas, legislator House of Lords SW1A 0PW
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I am surprised that the authors of this article did not also collect information on the local habit of chewing the tarry residues from opium smoking, which Professor Thomas Hewer established in the 1970s as the cause of elevated rates of oesophageal cancer in the region. Opium tar was chewed mainly by those too poor to afford opium itself. But then this finding got Tom Hewer into considerable hot water with the Shah: perhaps the current regime would be equally antipathetic to such a result? Lord Lucas Competing interests: None declared |
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Mostafa A. Elnaggar, fellow clinical oncology St Jame's Institute of Oncology St Jame's Hospital, ls97tf
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An interesting piece of information can be drawn fom this research because identifying such causative agents that can be easily modified can make a big difference in the incidence of such a tough disease, but more information is needed. Is this really about the tea itself or only about the temprature at which it is drunk? This should be compared with other hot drinks, especially hot water (considering water as a neutral liquid), to see if this association with cancer of the oesophagus applies to all hot liquids or only to tea and other similar drinks. Also it might be worth looking in a more general way to check the relation to other cancers in the head and neck such as the tongue and the pharynx, which like the oesophagus are subjected to hot tea. Competing interests: None declared |
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Charlotte A Davies, FY2, GP Bradford, BD6 9RJ
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Kirsten is absolutely right - it's how you make the tea that is important. I think that all tea should conform to British Standard 6008 (available http://www.bsi-global.com/en/Shop/Publication- Detail/?pid=000000000000090363 or summarised at http://www.guardian.co.uk/Archive/Article/0,4273,3908389,00.html) but if someone else is making it, I'm not fussy. Maybe we could repeat the study, using tea made conforming to British Standards? Competing interests: None |
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s chan, ST3 St Georges
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I wondered how much adding cold milk to black tea lowers the temperature. Also wouldn't drinking green tea be hotter as you never add milk to it. thanks Competing interests: None declared |
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John EA Somner, ST3 Ophthalmology The Tennent Institute of Ophthalmolgy,Gartnavel General Hospital Great Western Road, G120NY, Glasgow, Kirsten M. Scott
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Altitude alters the boiling point of water, meaning that Zimbabweans living in Harare (1472m) brew their Tanganda tea at approximately 90°C, Tibetans living in Lhasa (3658m) might take their Yak butter tea at approximately 74°C and Bolivians living in El Alto (4058m) are accustomed to brewing their coca tea at approximately 72°C. Iran is a country of geographical highs and lows, with an average altitude of 1200m ranging from 5628m at the Damavand summit in the central Alborz Mountains to 56m above sea level in the Lut Desert. Gonbad city, featured in this article(1), is situated at 187m, meaning that their preferred black tea will typically be boiled to approximately 99°C, while in Tehran, at approximately 1500m, black tea will be boiled at approximately 90°C. We wonder whether altitude might be a protective factor for the development of oesophageal carcinoma in large-volume hot-tea-drinking nations. If this study had been carried out in Tehran, perhaps an altitude effect would have negated the apparent effect of tea temperature in inducing oesophageal carcinoma. Secondly, with the widely recognized health implications of human-induced climate change and the health co-benefits of climate change mitigation strategies(2) we propose that a more discerning approach to our hot beverages may both reduce the risk of developing oesophageal carcinoma and reduce our carbon footprints. Experts recommend that green tea be brewed at 80°C, coffee at 90°C and black tea at 100°C. If we were to utilise intelligent kettles with variable temperature control we might reduce the energy consumption and CO2 emissions produced when brewing tea, coffee and hot beverages by 10-20%. In this case, dealing with climate change could have the lucky co-benefit of reducing the incidence of oesophageal carcinoma in hot beverage drinkers. If, however, we fail to deal adequately with the growing climate crisis perhaps rising sea levels will force more of us to move to the protective safety of the hills. 1.Islami F, Pourshams A, Nasrollahzadeh D, Kamangar F, Fahimi S, Shakeri R, Abedi-Ardekani B, Merat S, Vahedi H, Semnani S, Abnet CC, Brennan P, Møller H, Saidi F, Dawsey SM, Malekzadeh R, Boffetta P. Tea drinking habits and oesophageal cancer in a high risk area in northern Iran: population based case-control study. BMJ. 2009 Mar 26;338:b929. 2.Haines A, Kovats RS, Campbell-Lendrum D, Corvalan C. Climate change and human health: impacts, vulnerability, and mitigation. Lancet. 2006 Jun 24;367(9528):2101-9. Competing interests: None declared |
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Biji T. Kurien, Senior Research Scientist Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA, Yaser Dorri, Rachna Aggarwal, Anil D'souza, R. Hal Scofield
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We read with interest the article regarding tea drinking habits in Golestan province, northern Iran, showing that thermal injury increases the risk of oesophageal squamous cell carcinoma (ESCC) (1). Kangri cancer (squamous cancer of the skin) in Kashmir valley, India, has also been associated with thermal injury resulting from the constant contact of the hot Kangri pots (mud pot filled with hot embers) enclosed in a willow basket used by the not so well-to-do people of Kashmir beneath their traditional clothing to keep warm in the cold climate (2). On the other hand in certain areas of Andhra Pradesh, India, reverse chutta (a kind of cigar which is often smoked in reverse, i.e. the lighted end is placed inside the mouth), has been shown to induce more pre-malignant lesions and palatal cancer (squamous cell carcinoma) than conventional smoking (3,4). However, palatal cancer is not common in places where reverse smoking is not prevalent. These effects have been shown to be caused by pyrolysed tobacco products and intense heat. The temperature of the mucosa has been recorded as 58 ⁰C during reverse chutta smoking (3). While men in this area have been reported to smoke chutta in either the reverse or conventional style women have been reported to almost exclusively smoke chutta in the reverse fashion. Reverse smoking of chutta has been considered a more feminine way of smoking. The most prominent of all explanations provided for this habit is that the chutta is less likely to be extinguished by water splashed during household work and to avoid hot ashes falling on nursing infants (5). In the light of this evidence it is not clear as to how hot tea at temperatures greater than 65⁰C did not induce oral cancers in the residents of Golestan province, especially in conjunction with the fact that the authors have shown in an earlier study that opium, tobacco, hookah and nass chewing is widely used in the province of Golestan and has been shown to increase the risk of ESCC (1). In addition, hot foods have been demonstrated to increase ESCC risk (6). It would be of interest to determine the association of the temperature of the foods (stew, soup, ash reshteh etc) consumed by the subjects of Golestan province and ESCC risk. Hot solid food stays in contact with the oesophagus longer than tea does and could be more damaging and harmful, especially if this is habitual, similar to hot tea consumption. Therefore, we think that there would be more to ESCC risk than just hot tea drinking in these subjects. In addition, Golestan province is a state in north-east Iran with mild weather and temperature almost throughout the year. Based on this study, ESCC should be much higher in states in Iran that are very cold, since people tend to drink very hot tea (much higher than the temperature of the tea reported in this study1 due to cold weather. However, this is not the case in Iran itself, as reported by the author's themselves (1). Roughly 78% of the participants of this study consumed tea at a temperature that ranged from 60-64 ⁰C (1). Only 22% of study participants drank at 65 ⁰C and higher (1). Drinking hot beverages is a habit in many parts of the world and has not been associated with excessive ESCC (7) Here, it would be of interest to note that a recent paper has shown no association with hot tea consumption and ESCC. These authors suggest that hot tea consumption is inversely associated with ESCC as expected owing to the presence of protective polyphenols in tea (7). The fact that these subjects drank an average of a liter of tea (1) (~39% drank equal to/ greater than 1.7 litres of tea) everyday is of tremendous interest especially owing to the fact that tea has a very high oxalic acid content (8), which has been shown to be a critical risk factor for kidney stone formation (9) In fact, tea and coffee were reported to contain 80-85% of the dietary oxalate (8). It would be of interest to know whether the residents of Golestan (1) suffered from kidney stones. It is not mentioned whether the subjects in the study (1) used the curry spice turmeric/ curcumin in their diet. Curcumin, (1,7-bis[4-hydroxy -3-methoxyphenyl]-1,6-heptadiene-3,5-dione), the yellow pigment occurring in the curry spice turmeric obtained from Curcuma longa has emerged as a "nutraceutical" that is efficacious against colon cancer and other disorders (10). Turmeric is widely used in Asia and the Middle East as a dietary spice and for other purposes. The major problem with using curcumin is its lack of solubility in aqueous solutions. We have demonstrated an increase in the solubility of curcumin (12-fold) and that of turmeric (3-fold) by heating a solution of curcumin/turmeric in water to boiling for 10 minutes (10). Matrix assisted laser desorption ionization mass spectrometric and spectrophotometric profiling (400-700 nm) of the heat-extracted curcumin did not show any heat-mediated disintegration of curcumin. Actually heat treatment appears to protect curcumin against degradation (10). Employing an enzyme-linked immunosorbent assay that used 4-hydroxy-2-nonenal (HNE) modification of solid-phase antigen (11), the heat-solubilized curcumin/turmeric was found to inhibit HNE-protein modification by 80%. Thus, inhibition of HNE modification may be a mechanism by which curcumin exerts its effect in many disorders. Thus, the heat-solubilized curcumin is still bioactive. Therefore, we suggest that the civic leaders of Golestan, a province riddled with the reputation of having one of the highest incidence rates for ESCC in the world, should advocate residents to consider using heat- solubilized turmeric in their diet for the prevention of cancer. It would be of interest also, for the authors of this study (1) to consider using heat-solubilized turmeric/curucmin in a clinical trial for treating ESCC in Golestan (12). References 1. Islami F, Pourshams A, Nasrollahzadeh D, Kamangar F, Fahimi S, Shakeri R, et al. Tea drinking habits and oesophageal cancer in a high risk area in northern Iran: population based case-control study. BMJ. 2009 26;338:b929. 2. Suryanarayan CR. Kangri cancer in Kashmir valley: preliminary study. J Surg Oncol 1973;5:327-333. 3. Control of Tobacco-related Cancers and Other Diseases. International Symposium, 1990. Gupta PC, Jamner JE, iii and Murti PR, EDS. Oxford University Press, Bombay, 1992. 4. van der Eb MM, Leyten EM, Gavarasana S, Vandenbroucke JP, Kahn PM, Cleton FJ. Reverse smoking as a risk factor for palatal cancer: a cross- sectional study in rural Andhra Pradesh, India. Int J Cancer. 1993; 54:754 -758. 5. Gupta PC, Mehta FS, Pindborg JJ. Mortality among reverse chutta smokers in south India. Br Med J (Clin Res Ed). 1984; 289:865-866. 6. Chen YK, Lee CH, Wu IC, Liu JS, Wu DC, Lee JM et al. Food intake and the occurrence of squamous cell carcinoma in different sections of the esophagus in Taiwanese men. Nutrition. 2009 Apr 24. [Epub ahead of print] 7. Lagiou P, Talamini R, Samoli E, Lagiou A, Ahrens W, Pohlabeln H et al. Diet and upper-aerodigestive tract cancer in Europe: the ARCAGE study. Int J Cancer 2009;124:2671-2676. 8. Gasinska A, Gajewska D. Tea and coffee as the main sources of oxalate in diets of patients with kidney oxalate stones. Rocz Panstw Zakl Hig. 2007;58:61-67. 9. Kurien TB, Selvam R. Induction of lipid peroxidation in calcium oxalate stone formation. Indian J Exp Biol 1989;27:450-453. 10. Kurien BT, Singh A, Matsumoto H, Scofield RH. Improving the solubility and pharmacological efficacy of curcumin by heat treatment. Assay Drug Dev Technol 2007;5:567-576. 11. Kurien BT, Scofield RH. In vitro modification of solid phase multiple antigenic peptides/autoantigens with 4-hydroxy-2-nonenal (HNE) provide ideal substrates for detection of anti-HNE antibodies and peptide antioxidants. J Immunol Methods 2005;303: 66-75. 12. Kurien BT, Scofield RH. Heat-solubilized curcumin should be considered in clinical trials for increasing bioavailability. Clin Cancer Res 2009; 15: 747. Competing interests: None declared |
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Aline Marcadenti, MSc Hospital Nossa Senhora da Conceição, Rio Grande do Sul, Brazil, 91350-200, Erlon O. de Abreu-Silva, MD
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Islami et al showed a strong association between hot tea intake and higher risk of oesophageal cancer and it has been reported with other type of hot beverages in different parts of the world (1, 2). But some considerations must be made. First, authors showed data about temperature, frequency and amount of tea consumed by habitants of Golestan, but differently from other studies (1) they not informed the age whose people started to drink hot/very hot tea, and lifetime exposure seems equally important too. Second, there is no information about other risk factors of oesophageal cancer previously reported like temperature of meals (3) and saturated fat intake (4). And third, as commented by authors, some data were collected by recall bias-subject instrument. (1) Launoy G et al. Oesophageal cancer in France: potential importance of hot alcoholic drinks. Int J Cancer 1997,71:917–923. (2) Castellsagu’e X et al. Influence of mate drinking, hot beverages and diet on esophageal cancer risk in South America. Int J Cancer 2000, 88:658–664. (3) Hu J et al. Risk factors for oesophageal cancer in northeast China. Int J Cancer 1994, 57:38–46. (4) Launoy G et al. Diet and squamous-cell cancer of the oesophagus: a French multicenter case-control study. Int J Cancer 1998, 76:7–12. Competing interests: None declared |
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Yaser Dorri, Research Technician University of Oklahoma Health Scinece Center, Department of Medicine, 73104
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I read your comment with interest however, I could not wait to ask what your definition of gulping is? You have mentioned in your comment that Iranians "pour a little bit of the concentrated tea in their small glass cups" and add boiling water and "gulp it right away". As can be seen on the video, posted by BMJ, none of the people in the video gulped their tea right away! If I am wrong, please respond back and let every one know which of the participants in the video gulped their tea. I, as an Iranian, do not gulp tea and my relatives in several provinces of Iran do not gulp tea either! Perhaps there are some that do gulp tea, but I am not sure whether it is good to generalize it to all Iranians as you did in your comment. The other comment is about "concentrated tea". You mentioned that Iranians make concentrated tea and pour a little bit of concentrated tea in their small glass. Again, you have generalized this to all Iranians. There are many Iranians that do not make concentrated tea as they like to make fresh tea several times a day. In fact, many Iranians do not make concentrated tea simply because it becomes old and they do not like the taste of old tea. Therefore, the tea that they make over the Samavar is not concentrated. Moreover, we fill ¾ of a cup with tea and only ¼ with hot water and again, there are many Iranians who do not gulp tea, including those in the video clip posted by BMJ, which showed people in the province of Golestan. Having more information about a nation's culture and its people would really help not to completely disregard a method, namely tea making. Competing interests: None declared |
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Belinda Stanley, Consultant in Genitourinary Medicine North Cumbria University Hospitals NHS Trust
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If the stratified squamous epithelium lining the oesophagus is abnormal does it enable the drinking of fluids at hotter temperatures? How long does it take to develop oesophageal malignancy? Might the increased ability to drink tea at hotter temperatures be secondary to damage that has already occurred? Most of us test whether our tea is yet cool enough to drink, and then drink it. We learn how long it usually takes, occasionally trying a sip earlier than previous experience has suggested is sensible. If we discover that we have not had to wait as long for our tea to cool as previously, it would be possible to 'learn' that it could be drunk earlier (and at a higher temperature). Competing interests: None declared |
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Dr Viera Scheibner PhD, Scientist (retired) / Author Blackheath NSW Australia
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Dear Editor and all contributors to this most interesting debate, I feel that it is only a common sense, even without conducting any research, that we should consume drinks and food of any kind, close to the temperature of human milk. Anything much above and much below can only be harmful, short or long term. Competing interests: None declared |
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Nazan Karaoglu, Assistant Professor, MD Medical Education and Informatics Department, 42080, Konya, Turkey.
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Dear editor, I read the interesting article of Islami et al. and all the rapid responses with some questions in my mind (1). First of all I am from Turkey which has some similarities in eating, drinking and smoking habits. I want to ask my questions: 1- In a detailed questionnaire why the authors did not ask the smoking habits more detailed. I think the beginning age of smoking, the style of smoking, the amount of tobacco are all important. 2- I want to ask about helicobacter pylori infection. In Turkey in semptomatic patient the prevalence of H. Pylori is 86% (2) There is a debate about this issue as mentioned before (3). Some authors points out that populations with the higher rates of H. pylori infection have a higher oesophageal squamous cell carcinoma to oesophageal adenocarcinoma ratio especially males and CagA seropositivity rates seemed to have no additional effect on this (4). Another study notes the failure to suggest a significant association between H. pylori infection and oesophageal squamous cell carcinoma (5). I think the prevalence of H. pylori infection seems to be important in the study we discussed (1). With my respects, References 1- Islami F, Pourshams A, Nasrollahzadeh D, et al. Tea drinking habits and oesophageal cancer in a high risk area in northern Iran: population based case-control study. BMJ 2009; 338: b929 2- Sandýkcý MU, Doran F, Koksal F, et al. Helicobacter pylori prevalance in a routine upper gastrointestinal endoscopy population. Br J Cli Pract 1993; 47: 187-9. 3-Islami F, Kamangar F. Helicobacter pylori and esophageal cancer risk: a meta-analysis. Cancer Prev Res 2008; 1(5): 329-38. 4-Robins G, Crabtree JE, Bailey A, et al.International variation in Helicobacter pylori infection and rates of oesophageal cancer. Eur J Cancer 2008; 44(5):726-32. 5-Zhuo X, Zhang Y, Wang Y, et al. Helicobacter pylori infection and oesophageal cancer risk: association studies via evidence-based meta- analyses. Clin Oncol 2008;20(10):757-62. Competing interests: None declared |
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Kamal Chaouachi, Tobacco researcher and consultant Paris and Middle East.
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The related tobacco
smoking patterns (Nazan Karaoglu. Rapid Response, 9 May 2009) have in fact been
clarified in a previous study by the same team [1]. As for opium chewing
as a potential confounder (Ralph Lucas. RR, 7 Apr 2009), the same paper
mentions “sukhteh” as an ingested form of this drug [1]. In the study on
the association of hot tea drinking with oesophageal cancer, the authors state
that they used logistic regression models to adjust, among others, for tobacco or opium
use [2]. Interestingly, these researchers had previously
found a possible association between hookah tobacco smoking (only in intensity
but not in duration) and oesophageal cancer risk. They have also discarded opium smoking in hookah as a
possible confounder [3][4]. Certainly, the many ways tea is prepared or
drunk should be taken into account. Furthermore, there may also be other
confounding factors in the local environment
itself. In a recent study, the same researchers mention, among others, polycyclic aromatic hydrocarbons,
N-nitroso compounds and drinking water contaminants [5]. On the one hand, (contaminated) water might be a
confounder for hookah use since the smoke of the latter is water-filtered.
Notably, the tobacco (tumbeki) itself, which is packed in the bowl at the top
of the pipe, is previously soaked, for hours
sometimes. On the other hand, and since
Yaser Dorri’s anthropological input (RR, 1 May 2009) emphasised that “having more information about a nation's
culture and its people would really help not to completely disregard a method,
namely tea making”, it would not be irrelevant in future studies on this
issue to contemplate the fact that (hot) tea drinking is a key component during
the daily traditional hookah parties in Iran. _________________ [1] Nasrollahzadeh D, Kamangar F, Aghcheli K, Sotoudeh M, Islami F,
Abnet CC, Shakeri R, Pourshams A, Marjani HA, Nouraie M, Khatibian M, Semnani
S, Ye W, Boffetta P, Dawsey SM, Malekzadeh R. Opium, tobacco, and alcohol use
in relation to oesophageal squamous cell carcinoma in a high-risk area of
Iran.Br J Cancer. 2008 Jun 3;98(11):1857-1863. [2] Islami F, Pourshams A, Nasrollahzadeh D, Kamangar
F, Fahimi S, Shakeri R, Abedi-Ardekani B, Merat S, Vahedi H, Semnani S, Abnet
CC, Brennan P, Møller H, Saidi F, Dawsey SM, Malekzadeh R, Boffetta P. Tea
drinking habits and oesophageal cancer in a high risk area in northern Iran: population based
case-control study. BMJ. 2009 Mar 26;338:b929. http://www.bmj.com/cgi/content/full/338/mar26_2/b929 [3] Chaouachi K. Hookah, opium and tobacco smoking in
relation to oesophageal squamous cell carcinoma. Br J Cancer. 2009 Mar 24;100(6):1015 http://www.nature.com/bjc/journal/vaop/ncurrent/abs/6604958a.html [4] Malekzadeh R, Nasrollahzadeh D, Kamangar F. Reply: Hookah, opium, and tobacco smoking in relation to ESCC. Br J Cancer. 2009; 100 (6): 1016. [5] Islami F, Kamangar F,
Nasrollahzadeh D, Møller H, Boffetta P, Malekzadeh R. Oesophageal cancer in
Golestan Province, a high-incidence area in northern Iran - A review. Eur J Cancer. 2009 Oct 1. [Epub ahead of
print] http://www.ncbi.nlm.nih.gov/pubmed/19800783 Competing interests: |
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