Coffee and Tea Linked to Lower Cancer Risk

New evidence suggests that drinking black tea and caffeinated coffee daily may be associated with a lower risk of endometrial cancer in women. Endometrial cancer affects the lining of the uterus and is most common among women who are between the ages of 60 and 70.

Researchers surveyed 1,100 women about their consumption of black tea, decaffeinated coffee and caffeinated coffee. Half of the women were diagnosed with endometrial cancer.

They found that women who drank more than four cups of coffee and tea daily were about 50 percent less likely to develop endometrial cancer. Women who drank more than two cups of black tea daily were about 44 percent less likely to develop the disease. Additionally, women who drank more than two cups of coffee daily were 29 percent less likely to develop cancer, although this trend was not statistically significant.

It is unclear how black tea and coffee may help prevent endometrial cancer. The authors suggest that the results may be attributed to caffeine because decaffeinated coffee was not linked to a decreased cancer risk.

Laboratory and animal studies report that components of black tea, such as polyphenols, have antioxidant properties and effects against tumors. However, effects in humans remain unclear.

Additional research is needed in this area before a conclusion can be made.

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

Comments

[Elizabeth B.]

I think this is a very interesting topic. Caffeine has been reported to have beneficial effects on the modulation of circulating estrogen levels, as a result, may effect the development of hormone-related cancers. I came across another study from 2007 that also suggested that compared to non-coffee drinkers, coffee drinkers had a reduced risk of developing endometrial cancer.

[Lee]

This article provides interesting information about drinking more coffee and tea and lowering the risk of endometrial cancer. Some other factors that also may lower the risk of endometrial cancer are weight loss and diabetes control.

[Brandon]

The exact mechanism of how coffee and tea may reduce the risk of endometrial cancer is not known; however, coffee and tea contain certain compounds (besides caffeine) that may protect the body from damage that may lead to the development of cancers in general. These compounds include: isoflavones, flavonoids and catechins. These compounds are antioxidants that protect cells from damage caused by free radicals. The free radicals steal electrons which may potentially cause damage to DNA, possibly resulting in the development of cancer. However, in that case, I’m not sure how decaffeinated coffee would have a different effect from regular coffee. I guess, like Elizabeth stated above, estrogen level is a big factor in endometrial cancer.

[Sarah D.]

I also heard that weight reduction can decrease the risk of endometrial cancer. I think it has to do with the fact that fat tissue can convert other hormones into estrogens. Fat tissue also produces estrogen. Since endometrial cancer is a cancer that is linked to increased levels of estrogen, a person who is obese may be at a greater risk of developing endometrial cancer. Consequently, weight reduction may decrease this risk.

[Karen]

Four cups of coffee a day seems like a lot to me. When I see similar studies, I always wonder when the cancer protective effects are worth increasing consumption of a certain food or drink to such high levels. Isn’t drinking that much coffee a day bad for you? Anyone know more about this?

[Jason]

Wow, this is very interesting! I actually do drink a lot of coffee, but I’m trying to cut down on my caffeine intake, so I’m disappointed there were no benefits of drinking decaffeinate coffee. I have read news stories on Natural Standard about drinking green tea for reducing the risk of breast cancer and lowering blood pressure. Does black tea have similar effects?

[Marie]

It’s good to see a study that shows a more conclusive link between caffeine and its anti-cancer effects. I hope future research can focus on caffeine alone, so you will be able to tell whether caffeine's or tea’s antioxidant effects are at play here.

[Elisabeth Burns]

It is increasingly hard to know what to make of studies that examine tea and its affects on human health. This study shows a link between black tea and protection from endometrial cancer for women. Just back on March 27, another report explains how researchers found a link between drinking hot black tea and an increased risk for esophageal cancer. It would be great if researchers could compile all of their findings on tea, put their heads together and give us some firm information and/or more focused directions for their future studies.

[A Mar]

The study says they questioned the participants in the study about their coffee use the few years prior to diagnosis of endometrial cancer. One of the most serious risk factors for endometrial cancer is increased exposure to estrogen, as would occur in early menarche, late menopause, etc. which are lifetime risk factors. It seems that assessing lifelong or habitual caffeine use would have been more appropriate.

[R Day]

Usually people who are drinking that much coffee or tea are doing it for a reason – for some reason I’m thinking CEOs, doctors, nurses, teachers, “soccer moms” and the like. I would think that having such an active lifestyle would also have health benefits, as long as stress and/or smoking didn’t negate the benefits.

[Tim N]

The problem with these retrospective case-control studies is that it is so hard to show any sort of causality. People’s lives are so varied and complicated that pointing to a beverage choice to make conclusions about cancer risk reduction is really hard. The study was conducted via questionnaire from 1982 to 1998. According to the study, the PEDS questionnaire was a 16-page self-administered instrument covering information on tobacco and alcohol consumption, family history of cancer, occupational and environmental exposures, reproductive and medical histories, medication and vitamin usage and diet. Diet in the few years before diagnosis was queried using a brief 44-item food frequency questionnaire (FFQ). Beverages were asked separately from the FFQ and included questions on daily cups of coffee, decaffeinated coffee and black tea. Although herbal tea was queried, very few patients reported drinking this type of tea; therefore, these analyses include black tea only. I would have also liked to see questions on sleep and exercise. I wonder if there other high-antioxidant foods or beverages in the people who didn’t have endometrial cancer.

[Bretton]

Is anything else removed from coffee besides caffeine (i.e., polyphenols, isoflavones, flavonoids and catechins) in the decaffeination process? If not, and since the study shows no protection offered by decaffeinated coffee, wouldn’t that seem to show that the benefit is due to caffeine?

[Jon B]

Unfortunately this study did not address a very important question: Starbucks’ or Dunkin’s? Dunkin’s usually uses more lightly roasted beans, so I bet their coffee beans still have more of what’s good for you – caffeine, polyphenols, isoflavones, flavonoids and catechins, or whatever.

[JZ]

I wonder if a cup is the typical 8 oz. cup. I drink four of those no problem.

[Charlie G]

Interestingly, another study showed a protective effect against hypertension from drinking four or more cups of coffee. Prospective studies suggest a protective effect of high-coffee intake (four or more cups per day) against hypertension, mainly in women. Furthermore, the risk of hypertension may be lower in coffee abstainers (Vasc Health Risk Manag. 2008;4(5):963-70).

[Charlie G]

Another study showed that caffeine protects the heart. A recent prospective epidemiologic study found a strong protective association in elderly subjects without moderate-to-severe hypertension. Caffeinated coffee consumption was associated with lower risk of coronary heart disease (CHD) mortality and heart valve disease development or progression in older Framingham subjects without moderate or severe hypertension. (Am J Cardiol. 2008 Dec 1;102(11):1502-8. Epub 2008 Sep 11).

[Wanda W]

This blog is very interesting. I always put coffee in the same breath as cigarettes, but it seems that it has benefits far beyond helping you wake up. I don’t think coffee needs any marketing boost, but maybe these studies are something the corporations can put in their back pocket. “Why stop at 16 oz when 32 oz is healthier?” or, “A pot a day keeps the doctor away.”

[Jen H]

I remember the issue with the tea causing cancer was the temperature of the tea when the people drank it. I don’t think the temperature of the coffee would affect the endometrium.

[Seth M]

I love the curiosity of people, and I find the attitude of “It doesn’t work until we know why it works” to be fascinating. Caffeine, tannins, polyphenols, antioxidants – they’re all good. Nature is good for nature. A balanced diet and exercise is good for you. Eat right and take a walk. What’s the problem?

[Kara]

I agree, Karen. Four cups of coffee per day does sound like a lot of coffee. I do wish they would quantify amounts in these studies. What is a cup of coffee? Four ounces? Six ounces? Is that pertinent to the study? How will we know unless it's included? I only drink one cup of coffee each morning - but it's a 16-ounce cup. Does that make me safer from endometrial cancer or just more caffeinated?

[S. Yang]

Its easy to say what’s good for you – but what’s the BEST? And how can I back up and excuse my vices with science? Isn’t that what being a modern person is all about?

[Amber]

I find this interesting, but drinking four cups of coffee per day cannot be healthy. I read that drinking more than three cups of caffeinated beverages per day can disrupt sleep cycles, increase high blood pressure, increase blood sugar levels, increase heart rate, cause stomach problems and even cause breast tenderness. There must be other things that can help prevent endometrial cancer. What about people who cannot drink caffeine due to other disorders, such as generalized anxiety disorder or diabetes? Caffeine cannot be the only answer to this problem.

[JKL]

I have to disagree with you, Amber. I don't think that four cups of coffee is a lot (at least if each cup contained just eight fluid ounces). I think a Dunkin' Donuts medium coffee is about 20 ounces, which is more than three cups. And a lot of people drink coffee in the morning and again in the afternoon.

[Healthybody]

If it is the caffeine that helps prevent endometrial cancer, then does eating chocolate provide the same benefit? I am obviously talking about good dark chocolate that at least has 70% of cocoa. Dark chocolate contains caffeine and has antioxidant properties. It also reduces bad cholesterol (LDL) and lowers blood pressure. I don’t drink coffee or black tea, but I sure could eat chocolate every day to help prevent endometrial cancer!

[Michelle]

This is a reply to Jason’s comment above about the health benefits of green tea vs. black tea. Black tea primarily has theaflavins; while, green tea has catechins. I came across several studies indicating that black tea helps to improve the functioning of blood vessels and reduces the risk of coronary heart disease. However, green tea is reported to have more polyphenols than does black tea. The antioxidant capacity per serving of green tea is higher than that of black tea, according to a study published in The Journal of Nutrition. I also read that both green and black teas have EGCG, an antioxidant that has been shown to inhibit cancer cell growth, but green tea has higher concentrations of this compound.

[Isabelle M.]

Studies demonstrate the benefits of caffeine (coffee and tea). What about energy drinks? They can have anywhere from 150 to 500 mg of caffeine per drink.

[Laura]

I read about drinking a maximum of three cups of coffee a day, as well. I believe this refers more to the amount of caffeine and not the number of cups. The general advise offered on the “Health Canada” Web site is not to consume more that 400 mg of caffeine per day, which is equivalent to about three 8-ounce cups of coffee. However, other sources argue that consuming anymore than 300 mg (two cups) of caffeine a day can have negative consequences.

[Alex]

I read an article that discussed the possibility that caffeine may protect a person from developing Alzheimer’s disease. This may be due to caffeine’s effect on dopamine. Has anyone read any studies supporting this?

[Sam]

I actually found several studies that discuss the effect of caffeine on neurodegenerative diseases like Parkinson’s and Alzheimer’s diseases. It has been argued that oxidative stress may play a big role in these diseases; as a result, antioxidants may positively impact cognitive function. In addition, caffeine is an adenosine A2A receptor antagonist that has been reported to enhance locomotor activity in animal models of Parkinsonism. A2A receptors play a role in neuronal injury and deterioration.

[Zack]

I read a study that evaluated the association of caffeine with the risk of developing Parkinson’s disease. The study followed people over a period of 30 years. The results indicate that consumption of caffeine is associated with decreased risk of Parkinson’s disease. I thought this was very interesting and worth investigating further.

[V. Stein]

I wonder what the baseline characteristics of the participants in this study were like, and if the coffee drinkers and non-coffee drinkers had similar diets, lifestyles and co-morbidities. The link between coffee and tea in lowering rates of endometrial cancer is definitely something that I would like to see studied further, as this research does look promising.

Also to answer Sarah D above, excessive coffee drinking has been found to have some promising health benefits, such as decreasing rates of H. pylori infection in a study published in BMJ, as well as lowering the risk of type 2 diabetes in a study published in JAMA; although of course, more long-term studies are still warranted in those areas. Coffee intake has its downsides as well, such as increasing systolic and diastolic blood pressure.

[BD]

This is an interesting fact, but what kind of harmful effects can we expect to see from drinking four or more cups of coffee daily. We must delve deeper and isolate which specific compounds could be causing this reduction in endometrial cancer. We always are being fed differing reports of coffee, tea and other caffeinated beverages. An all-encompassing report should be done where we can weigh the risks versus the benefits based on individual characteristics and disease states and person may have. Surely, a woman with uncontrolled hypertension or post-MI shouldn't be drinking four cups of coffee every day because she's worried about endometrial cancer.

[Joann]

It is important to note that although it seems as if black tea and coffee reduce the cancer risk, they do not come without risks of their own. For people who have heart or GI conditions or are taking certain medications, such drinks would not be recommended. Also, if there were direct, reliable conclusions made from a study, I’m sure there would be a market for producing the easy-to-take supplements of the active ingredients. This would probably make more sense for people who do not normally consume large amounts of these drinks rather than suddenly increasing their intake to more than four cups of coffee or tea per day.