Drinking Hot Tea may be Linked to Esophageal Cancer

According to a new study published in the British Medical Journal, drinking hot black tea may increase the risk of esophageal squamous cell carcinoma, the most common type of esophageal cancer. 

In the latest study, researchers studied the tea-drinking habits of 300 people diagnosed with esophageal squamous cell carcinoma and 570 healthy people (controls). The participants were from northern Iran's Golestan province. This area has a very high rate of esophageal squamous cell carcinoma even though smoking and drinking, two major risk factors for the disease, are not common.

The researchers found that nearly all participants (98 percent) regularly drank black tea. On average, they drank a little more than a liter daily. People who drink hot tea (140-147 degrees Fahrenheit) or very hot tea (hotter than 149 degrees Fahrenheit) were about two and eight times more likely to develop cancer, respectively, than people who drank warm or lukewarm tea (140 degrees Fahrenheit or less). 

The speed with which people drank their tea also affected cancer risk. People who drank a cup of tea in less than two minutes after it was poured were about five times more likely to develop cancer than those who took longer than four minutes. The amount of tea consumed did not affect cancer risk.

The researchers went on to study 48,582 residents in the same area. Participants in the cohort study were served tea and asked their preferred tea temperature, which was checked with a digital thermometer. They found that 39 percent drank warm or lukewarm tea, 39 percent drank hot tea and 22 percent drank very hot tea.

However, because this is an observation study, it does not prove cause and effect. It is unclear if hot tea actually causes esophageal cancer or if other hot drinks may have this same effect. Additional studies are warranted in this area.

For more information about black tea, please visit Natural Standard’s Foods, Herbs & Supplements database.

Comments

[Jack Pratt]

I guess if you stress the lining of your throat by constantly burning the outer layer either 1) the repeated need to replace damaged cells could increase the chances for a cancerous cell to be produced, or 2) the damaged cells would be unable to fend off carcinogenic insults resulting in an increased risk for cancer.

[Kara]

I would assume that these results would be similar among people who drink other hot beverages, like coffee. But I guess the major difference is that more people probably drink their tea black than their coffee, and adding cream or milk helps cool it down.

[Jim]

This is good information to know because I prefer my tea black. I will now wait five minutes for it to cool before drinking it.

Some earlier studies have suggested that components of tea, such as polyphenols, have antioxidant properties and effects against tumors. However, other studies suggest that constituents in black tea may be cancer-causing. So it appears that there are a lot of uncertainties about the relationship between black tea and cancer.

[Jill Thomson]

Interesting that the temperature seems to play a role, and I would love to hear an expert speculate on Jack's comment that this may be connected to cell damage in the throat. It seems to me that the amount of tea consumed should have changed cancer risk, but maybe once the damage to the throat cells is done, it's done, and you can drink all you want?

Also, might there be a link between caffeine and cancer? Natural Standard reports that 1 cup of black tea contains about 50 milligrams of caffeine, though this depends on the strength and size of cup. Caffeine has been linked to a number of short- and long-term health consequences - could this be another?

[Rebecca]

This article is interesting and made me think. My uncle is 68 years old and actually has squamous cell carcinoma. I don’t know if there is a definite correlation between squamous cell carcinoma and the consumption of very hot black tea, but for as long as I’ve known my uncle, he has always ate and drank only extremely hot foods and beverages. In the end, I think it makes sense that damage and stress to the throat may be a contributing factor to the development of esophageal cancer.

[Sophie]

I think that reducing the temperature of the tea that we consume is a good idea, but I don't think we should give up on black tea altogether. According to the National Cancer Institute, black tea contains a good amount of flavonoids, or flavonoid-related compounds with strong antioxidant effects. They soothe athersclerotic inflammation, reduce thrombosis and promote normal endothelial function. Black tea may also reduce the risk of cancer, heart diseases and degenerative diseases.

[Kara]

As someone who prefers tea and coffee very warm, I look forward to seeing more information on this topic emerge. Jack's comments make logical sense, but I wonder if there are compounds in the black tea that are carcinogenic or if it is just that a conducive environment is being created for cancer? There are so many positive effects to drinking black tea, as Sophie notes, that I would need to see to strong evidence before I gave up my tea.

[Beth B]

This looks like a topic that will be kicked around for a while. An article just released in the International Journal of Cancer (June 2009, http://www.ncbi.nlm.nih.gov/pubmed/1923002 ) looked at dietary habits of over 2,300 people in 10 European countries. They found opposite results from the study reported in this blog: There was NO increase in esophageal cancer in people who drank hot tea in the Intl J of Cancer study.

[Anne-Marie]

Beth missed the chance to mention a related article, in the April 2009 issue of the Intl Journal of Cancer (http://www.ncbi.nlm.nih.gov/pubmed/19123468 ). This research looked at the drinking of very hot GREEN tea in China, instead of black tea. The scientists found that drinking hot green tea increased the risk of developing esophageal cancer. Personally, I think that ANY hot liquids may cause damage to cells in the throat. It makes sense that years (or decades) of damage to cells, no matter where they’re located in the body, has a good chance of leading to cancer.

[Jessica T.]

Sophie, I totally agree with you about the benefits of black tea. My first thought was "why is black tea being linked to esophageal cancer?!" Tea has antioxidant properties and is generally considered good for you. The concept of the temperature of the liquid you drink being linked to the development of cancer is something I have never heard of, but it makes sense!

[Drew Potter]

I drink 2-3 cups of tea every day, so this study caught my attention immediately. I find myself thinking that it is the temperature of the liquid rather than the tea itself that could be linked to cancer. Does anyone know how quickly the cells in the esophagus are replaced? I would imagine that they would be able to recover from damage pretty quickly, but then again, if the cells are constantly exposed to this extreme heat, maybe not?

[J.D.]

I'm curious about what else was included in the diets of the subjects in the study Beth B. mentioned. I think it is difficult to isolate the effects of hot tea in 2,300 people since there are so many other factors to account for. Also, what temperature does the tea have to be in order to be hot or very hot? It is an interesting observation, and more study definitely needs to be done.

[L.B.]

I wonder if these results would hold if the authors controlled for age. If hot tea damages or stresses the esophagus, it might do the same to the tongue. This damage might impair tea drinkers’ ability to detect hot temperatures. Tea drinkers might require, over many years, hotter and hotter tea. Drinking very hot tea, therefore, might be a trait of older people who have had time to build up a tolerance to heat. These same people could be at increased risk for cancer not only because of their tea habits but also because of their advanced age.

[Samantha]

After reading this article, I wondered about how hot the “hot beverages” served at restaurants and coffee shops are. I became a little concerned because I don’t know about anyone else, but personally, I start drinking these beverages immediately after they are brought to me. I read that in the U.S. the hot beverages are served at temperatures up to 80°C (176°F), according to data from an investigator survey. While searching for this information, I came across a McDonald's Lawsuit from 1994, which involved a woman getting severe burns after spilling a cup of coffee she received a few minutes prior. The coffee was around 180°C. I wonder if after that lawsuit restaurant regulations changed.

[Aaron]

I came across a curious study on Pubmed from the British Journal of Cancer. This was a population-based case-control study conducted nationwide in Sweden. The results of the study indicated that drinking very hot beverages did not increase the risk of esophageal cancer. I thought this was very interesting because the results of this study contradict a lot of other available data; however, I was not able to find the full text article in order to evaluate the study in greater detail.

[Susan L.]

I read an article in Science Daily that also mentioned that drinking very hot tea (70°C or more) can drastically increase the risk of cancer of the esophagus. Several previous studies have reported an average temperature preference of 56-60°C among healthy populations; as a result, it is important to inform the population about the dangers of drinking very hot tea. It is an easily modifiable risk factor, so it would be a shame to disregard it.

[krisha]

Oh! Glad I saw this post. Almost half of my family drinks tea. We didn't know that people who drank a cup of tea in less than two minutes after it was poured were about five times more likely to develop cancer than those who took longer than four minutes. This post must be read by everyone. Thanks for the information.

[Cory]

This observational study regarding esophageal cancer and drinking hot tea has little-to-no clinical relevance. The general risk factors that increase an individual's risk of cancer are age, ethnicity, gender, diet, h-pylori infection, smoking, other disease states (like long-term inflammation of the stomach) and genetics.

According to the Natural Standard monograph on esophageal cancer, no information about hot tea intake and esophageal could be found. Extensive, evidence-based study will be needed before recommendations for or against hot tea and esophageal cancer could be concluded.

Also, studies done in other countries might not be applicable to U.S. residents. In order to confirm the validity of these results, more evidence-based study must be done in the U.S.