Green Tea: New Benefits

Two new studies suggest that more health benefits may be associated with the popular Chinese beverage, green tea.

Green tea is made from the dried leaves of Camellia sinensis, a perennial evergreen shrub. Green tea, black tea and oolong tea are all derived from the same plant. Green tea is produced by lightly steaming the freshly cut leaf, thus not allowing oxidation of the enzymes within the leaf to take place. Green tea is produced and consumed primarily in China, Japan and countries in North Africa and the Middle East. Green tea is used as an antioxidant and has been studied for weight loss and chronic disease prevention.

Researchers have discovered new evidence suggesting that green tea may reduce the risk of oral cancer as well as help treat inflammatory skin diseases.

In the first study, researchers from Japan examined the relation of green tea consumption with oral carcinogenesis (cancer) by prospectively analyzing data from a nationwide large-scale cohort study in Japan.

A total of 20,550 men and 29,671 women aged 40-79 years, without any history of oral and pharyngeal cancer at baseline survey, were included in the study. During a mean follow-up period of 10.3 years, 37 oral cancer cases were identified.

The study found that women who drank five or more cups of green tea a day may have a reduced risk of mouth cancer. In men, no such trends were observed.

The study authors concluded that there was not enough evidence to suggest that green tea consumption is correlated with oral cancer. However, there was a tendency for a reduced risk in women.

In a related study, researchers suggested that green tea may help treat skin disorders such as psoriasis and dandruff. Scientists form the Medical College of Georgia studied the effects of green tea on inflammatory skin diseases in an animal model.

Skin diseases are characterized by patches of dry, red and flaky skin caused by the inflammation and overproduction of skin cells. Researchers suggested that green tea treatment may slow the growth of skin cells. They explained that green tea suppresses inflammation and regulates the expression of Caspase-14, a protein in genes that regulates the life cycle of a skin cell.

Researchers suggested that traditional inflammatory skin disease treatments result in harmful side effects. For example, ultraviolet light and medication, while they may control lesions and be used long term, they may also cause squamous cell carcinoma, the second most common form of skin cancer.

Additionally, some of the most effective anti-dandruff shampoos also have carcinogens in them with unknown long-term effects.

Researchers noted that one of the problems with using green tea as an alternative treatment is that the chemicals in green tea are so active that they are oxidized too quickly when mixed with other ingredients. They also dissolve in water, which cannot penetrate the skin's barrier.

Researchers are looking for a balanced formula that can dissolve in fats and permeate the skin.

The study authors concluded that while there are no cures for autoimmune diseases, it is possible that green tea may be a non-toxic way to regulate them. Further study in humans is needed to determine the full effects.

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

Comments

[DannyBoy]

"...some of the most effective anti-dandruff shampoos also have carcinogens in them..." Are we talking the stuff you can get in the store or the stuff you need a prescription for? Are they labeled that they can cause cancer? Seems like if you avoided stuff like that, you wouldn't need the green tea.

[D Martin]

As a psoriasis sufferer, I was very excited when I read the headline suggesting that green tea might help inflammatory skin conditions... I was ready to go out, buy some and start drinking it, even though I really can't stand green tea!

Then I read further and found that, due to how easily the chemicals are oxidized and the fact that they dissolve in water, the benefits are not available through drinking the tea, or even through applying it in a topical cream.

Oh well. I guess I won't be choking down any green tea after all. I do hope the research on green tea will continue, though. Those of us who suffer from inflammatory skin disorders know only too well the dangers and disappointments of available treatments.

[D. Scully]

Did the study on green tea for medical uses like dandruff put some chemicals from the drink directly on the skin?

I wonder if taking green tea capsules is just as effective as drinking the stuff. I don't think I'll ever get up to five cups a day! Do I need to take green tea capsules with warm water, so that tea is made in my tummy?

[A. Krychek]

I don't really understand the way this trial was conducted. It says there was a lower incidence of cancer in women but doesn't mention a control group. Couldn't it be that women are just less at risk for mouth cancer? Or women that drink green tea engage in a healthier lifestyles altogether?

[Evan]

D. Scully:

In order to preserve the nutrients in green tea, it should not be steeped in hot, boiling water anyway.

I wonder if matcha would prove more effective in this situation. Matcha is a powdered version of the green tea leaf that is supposedly better for you than traditional green tea, as most of the nutrients have been preserved. There are very few people who will actually drink 5 cups of green tea a day, so I wonder if two or three cups of matcha would be just as effective. I've never actually drank matcha, but I know it's used in a lot of different foods such as ice cream, mochi, and specialty chocolate bars.

[Jer]

It's too bad I hate the taste of green tea. Where can you buy green tea capsules? Are they labeled as something else...like the active ingredient?

[dalz]

Green tea has recently been heralded as the new wonder drug to cure it all! But who could actually consume enough of the stuff to see the added benefits without running to the bathroom every hour. Does green tea ice cream count?

[Tomlin]

Jer, I buy green tea capsules at Target and Trader Joe’s. They are also sold at my grocery store and CVS. They are a pretty popular items these days, so you could probably find plenty of places to buy online as well. Good luck!

[Joni]

Would mixing green tea with emu oil or DMSO work to get it through the skin?

[delia h.]

I am confused about how they studied the effects of green tea on skin disorders since it can't permeate through the skin. Did they only look at how the green tea affected the rate of the growth of the skin cells? If yes, how did they do this?

[Josh]

Are the green tea bags found in the grocery store good? Or is there a specific type of green tea to purchase that is good for you?

[Leigh]

My concern with green tea is the caffeine content. It has been linked to many benefits, but should people with high blood pressure be concerned? What particularly concerns me is all the weight loss supplements out there that contain green tea, and all sorts of different derivatives of caffeine. Is there green tea available that does not contain caffeine yet still upholds the same benefits?

[Water Point]

Josh – I think the type of green tea you purchase at the supermarket would be fine. I’m not sure if there are particular types of green tea or not, but the studies don’t usually specify. I’ve heard that black tea can be helpful for lots of stuff too, including bad breath!

[CR]

Five cups of green tea is quite a few, and I only know a few people that would successfully drink that much green tea daily. If this study is observational and over the course of the ~10 years, I wonder they had people fill out information, including how much green tea they drink, as well as any incidences of cancer along with a lot of other information. And if so, there’s not enough information to say certainly that green tea prevents oral cancer in women. All we can say is that there is a link between drinking more green tea and less oral cancer in women. There’s a lot of qualifiers there.

[Rilo]

I'm with Leigh. I can't have caffeine, but I would really like to include green tea in my diet, especially after reading about all the benefits it provides. I read somewhere that if you pour hot (not boiling) water over a green tea bag, dump out the cup and then refill it with hot water, most of the caffeine gets extracted with the first steeping, but about 80% of the nutrients remain. I wonder if this is true.

[Carol]

What about those little "on-the-go" packets made by Lipton to be dissolved in a bottle of water? Do they have enough green tea in them to have any actual benefit?

[Richard]

Some people might want to drink gallons of green tea to stay healthy, and that is their choice. But I prefer regular exercise and checkups with the doctor. And I prefer coffee over tea anyhow.

[dalz]

Carol- I think all the added unnecessary additives/sugar in the Lipton packets probably would cancel out any benefit of the green tea component for cancer prevent.

COME ON people! Oral cancer cannot be prevented by Camellia sinensis!

[Elliot]

I agree with Dalz. I think this is a bit of a stretch. Green tea seems to be very popular these days, so I guess the high interest creates a need for studies like this. I wouldn't use this as my sole basis for starting a green tea regimen.

[Josh]

Every other week there is different news on which is better- green tea, red tea, white tea, black tea, etc. Does anyone have any conclusive evidence on this?!

[Heather]

I know it may sound exciting that green tea decreased oral cancer in women, but I think instead of going out to buy a bulk of green tea, there are other ways to prevent oral cancer. First, quit smoking or using tobacco. This is the main cause of oral cancer. I know the study adjusted for smoking, but if the smokers quit, they would be less likely to get oral cancer. Alcohol is another risk factor, so decreasing your alcohol intake can be preventative as well. I’m sure green tea has many health benefits, but I think eliminating major risk factors may be a better option than drinking five cups of green tea a day.