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Very hot tea may cause throat cancer

by auhckw » Nov 27th, '10, 19:51

Slightly old news but I couldn't find it being posted... So here you go

Very hot tea may cause throat cancer ... 527642.htm

27 March 2009

Drinking hot tea may cause throat cancer, say Iranian researchers, suggesting people let their steaming drink cool before consuming them.

Previous studies have linked tobacco and alcohol with cancer of the oesophagus, and the research published in the British Medical Journal suggests that scalding beverages may also pave the way for such tumours.

Drinking very hot tea at a temperature of greater than 70 degrees Celsius was associated with an eight-fold increased risk of throat cancer compared to sipping warm or lukewarm tea at less than 65 degrees, the researchers write.

Professor Reza Malekzadeh of Tehran University of Medical Sciences and colleagues studied the tea-drinking habits of 300 people with oesophageal cancer and another 571 healthy men and women from the same area in Golestan Province in northern Iran.

That region has one of the highest rates of throat cancer in the world, but smoking rates and alcohol consumption are low, say the researchers. Nearly all the volunteers drank black tea regularly, consuming on average more than a litre each day.

People who regularly drank tea less than two minutes after pouring were five times more likely to develop the cancer compared to those who waited four or more minutes, the researchers say.

British studies have reported people prefer their tea at an average temperature of 56 degrees to 60 degrees, they note.

It is not clear how hot tea might cause cancer, but one idea is that repeated thermal injury to the lining of the throat somehow initiates it, say the researchers.

Cancers of the oesophagus kill more than 500,000 people worldwide each year, with the bulk of the disease occurring in discrete populations in Asia, Africa, and South America. The tumours are especially deadly, with five-year survival rates of 12 to 31%.

Earlier this week, US and Japanese researchers reported that about a third of East Asians - Chinese, Japanese and Koreans - have an enzyme deficiency that puts them at higher risk of developing oesophageal cancer when they drink alcohol.

Steaming hot tea linked to cancer

27 March 2009

Drinking steaming hot tea has been linked with an increased risk of oesophageal (food tube) cancer, Iranian scientists have found.

The British Medical Journal study found that drinking black tea at temperatures of 70C or higher increased the risk.

Experts said the finding could explain the increased oesophageal cancer risk in some non-Western populations.

Adding milk, as most tea drinkers in Western countries do, cools the drink enough to eliminate the risk.

The oesophagus is the muscular tube that carries food from the throat to the stomach.

Oesophagus cancers kill more than 500,000 people worldwide each year and oesophageal squamous cell carcinoma (OSCC) is the most common type.

Tobacco and alcohol are the main factors linked to the development of oesophageal cancers in Europe and America.

But it has not been clear why other populations around the world have high rates of the disease although there has been a theory that regularly drinking very hot drinks damages the lining of the gullet.

A litre a day

Golestan Province in northern Iran has one of the highest rates of OSCC in the world, but rates of smoking and alcohol consumption are low and women are as likely to have a diagnosis as men. Tea drinking, however, is widespread.

The University of Tehran researchers studied tea drinking habits among 300 people diagnosed with OSCC and compared them with a group of 570 people from the same area.

Nearly all participants drank black tea regularly, on average drinking over a litre a day.

Compared with drinking warm or lukewarm tea (65C or less), drinking hot tea (65-69C) was associated with twice the risk of oesophageal cancer, and drinking very hot tea (70C or more) was associated with an eight-fold increased risk.

The speed with which people drank their tea was also important.

Drinking a cup of tea in under two minutes straight after it was poured was associated with a five-fold higher risk of cancer compared with drinking tea four or more minutes after being poured.

There was no association between the amount of tea consumed and risk of cancer.

Because the researchers had relied on study participants to say how hot their tea was, they then went on to measure the temperature of tea drunk by nearly 50,000 residents of the same area.

This ranged from under 60C to more than 70C, and reported tea drinking temperature and actual temperature was found to be similar.

Tea lovers

Writing in the BMJ, the researchers led by Professor Reza Malekzadeh, said: "Our results showed a noticeable increase in risk of oesophageal squamous cell carcinoma associated with drinking hot tea.

"A large proportion of Golestan inhabitants drink hot tea, so this habit may account for a substantial proportion of the cases of oesophageal cancer in this population."

Previous studies from the UK have reported people prefer their tea to be about 56-60C - cool enough not to be risky.

In a BMJ editorial, David Whiteman from the Queensland Institute of Medical Research in Australia said: "The mechanism through which heat promotes the development of tumours warrants further exploration and might be given renewed impetus on the basis of these findings."

Dr Whiteman advised tea-drinkers to simply wait a few minutes for their brew to cool from "scalding" to "tolerable".

Oliver Childs, a spokesman for Cancer Research UK, said: "Tea drinking is part of many cultures, and these results certainly don't point to tea itself being the problem.

"But they do provide more evidence that a regular habit of eating and drinking very hot foods and drinks could increase your risk of developing cancer of the oesophagus."

He added: "People in this region of northern Iran often drink very hot tea as part of their daily routine. We're a nation of tea lovers in the UK, but we don't tend to drink tea at such high temperatures and we usually add milk, which cools it down."

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Nov 27th, '10, 20:50
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Re: Very hot tea may cause throat cancer

by JeiKun4114 » Nov 27th, '10, 20:50

Good post but in my opinion I think this study is flawed :? its not like you drink hot tea straight :idea: if it was so uncomfortable people would not be able to swallow it, again the tea is sipped so its cools rapidly over the surface area of the mouth. :mrgreen:

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Nov 28th, '10, 02:31
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Re: Very hot tea may cause throat cancer

by wyardley » Nov 28th, '10, 02:31

auhckw wrote:Slightly old news but I couldn't find it being posted...

Maybe look a little harder next time.

Dec 1st, '10, 14:30
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Re: Very hot tea may cause throat cancer

by beforewisdom » Dec 1st, '10, 14:30

I heard something similar about yerba mate drinkers getting cancer because they like the infusions to be very hot.

The problem I have with health claims for and against tea is that billions of people have been drinking tea for centuries.

People still get a variety of diseases that tea is supposed to help fight.

Tea drinkers aren't turning up with mouth cancer.

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Dec 1st, '10, 15:15
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Re: Very hot tea may cause throat cancer

by debunix » Dec 1st, '10, 15:15

It makes sense that if your tea is hot enough to scald you if it spills on you, it's probably too hot for your innards. And just as repeated sunburns are well known to increase risk of skin cancer, it makes perfect sense that repeated mild thermal burns to the esophagus could increase risk of esophageal cancer. Repeated irritation from stomach acid/heartburn/reflux definitely is associated with increased risk of esophageal cancer. In general, repetitive inflammation in a tissue, resulting in increased cell turnover (growth/division/proliferation), increases the risk of malignancy, because every time a cell divides, the risk of damage to the DNA is increased.

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Dec 1st, '10, 15:47
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Re: Very hot tea may cause throat cancer

by Alex » Dec 1st, '10, 15:47

I like to eat tea bags then pour a fully boiled kettle directly down my throat without touching the sides. this keeps the throat protected.

Dec 10th, '10, 01:14
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Re: Very hot tea may cause throat cancer

by tommetomtom » Dec 10th, '10, 01:14


Obviously you read it wrong as mate is brewed with a temp no higher than 180 degrees. Any higher produces a slightly bitter taste.

Plus the traditional way to prepare it is in a Gourd and before adding the hot water you moisten the mate with cool water.

Dec 10th, '10, 20:24
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Re: Very hot tea may cause throat cancer

by beforewisdom » Dec 10th, '10, 20:24

A study by the International Agency for Research on Cancer showed a limited correlation between oral cancer and the drinking of large quantities of hot mate. Smaller quantities (less than 1 liter daily) and warm rather than hot mate consumption were found to increase risk only slightly; alcohol and tobacco consumption had a synergistic effect on increasing oral, throat, and esophageal cancer. The increased risk, rather than stemming from the maté itself, could be credited to the high temperatures in which the mate is consumed in its most traditional way, the 'chimarrão'. The cellular damage caused by thermal stress could lead the esophagus and gastric epithelium to be metaplasic, adapting to the chronic injury. Then, mutations would lead to cellular displasia and to cancer.[33] Given the influence of the temperature of water, as well as the lack of complete adjustment for age, alcohol consumption and smoking, the study concludes that mate is "not classifiable as to its carcinogenicity to humans".[34]

Researchers in Mississippi found that both cold and hot water extractions of yerba mate contained high levels (8.03 to 53.3 ng/g dry leaves) of carcinogenic polycyclic aromatic hydrocarbons (PAHs) (i.e. Benzo[a]pyrene).[35] However, these potential carcinogenic compounds originate from drying process of the maté leaves, which involves smoke from the burning of wood, rather than from the mate itself.[36]

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