Tea Mail - April 2004 - Seven Cups Fine Chinese Tea

Green Tea Component Helps Kill Leukemia Cells
AScribe, 31 March 2004
Mayo Clinic researchers have discovered that a component in green tea helps kill cells of the most common leukemia in the United States. The research using laboratory cell cultures shows that a component of green tea known as epigallocatechin-3-gallate (EGCG) helps kill leukemia cells by interrupting the communication signals they need to survive. The findings are reported in an article in the journal Blood.

The leukemia cells studied were from patients with B-cell chronic lymphocytic leukemia (CLL) — most often diagnosed in patients in their mid-to-late 60s. Currently, there is no cure for CLL, though chemotherapy is administered in the most severe cases. The Mayo Clinic study, led by Neil E. Kay, M.D., shows that green tea’s EGCG interrupted survival signals, prompting leukemia cells to die in eight of 10 patient samples tested in the laboratory.

About the Leukemia called CLL
CLL affects individuals differently in the pace at which it progresses. Some patients may live with it for decades and not require treatment, while others need immediate treatment, and some die within months despite therapy.

Significance of the Mayo Clinic Finding
The CLL characteristics make this finding even more important, as it suggests a new, nontoxic treatment. Mayo Clinic CLL researcher Tait D. Shanafelt, M.D. said “Our research goal is to identify new treatments for CLL that have a favorable side effect profile and can be used in patients with early stage disease to prevent progression. I think we’re getting there.”

Why Green Tea?
Mayo Clinic researchers focused on green tea for at least three reasons. One, since the 1970s, epidemiological studies of cancer have shown that in parts of the world where green tea is consumed, the incidence of solid tumor cancers such as breast, lung and gastrointestinal cancers is lower. Secondly, mouse-model testing of green tea’s cancer-prevention properties has shown they protect against solid tumors. And three, in the laboratory, the EGCG component of green tea has been proven to induce death in cancer cells from solid tumors.

The Mayo Clinic research suggests EGCG works by inhibiting a pathway in the leukemia cells related to angiogenesis — the complex process that maintains nourishing blood flow to a biological structure, in this case a cancer cell.

More Reasons Brewing for Drinking Green Tea
EmediaWire, 28 Mar 2004
Recent studies show a daily dose of green tea can be helpful for everything from weight loss and sleeplessness to cancer. The news supporting the health benefits of drinking green tea continues to amaze consumers. Proof that green tea is good for body, mind and soul is growing.

Research at Rutgers University has confirmed that green tea has six times the antioxidant capability of fully fermented black teas, which seems to support what Eastern healers have known for centuries; green tea has extraordinary healing properties. Scientists around the world agree that drinking several cups of green tea each day can have a profound effect on your health.

Weight Loss
Based on continuing research, many scientists believe that caffeine in conjunction with EGCG (epigallocatechin gallate)—a highly active antioxidant in tea—may work together to increase fat oxidation.

“Our data suggests that a component of tea other than caffeine might have promoted preferential use of fat as an energy source,” says Beverly Clevidence, a coauthor of the study and head of the Diet and Human Performance Laboratory, Beltsville Human Nutrition Research Center, Maryland. “The interesting part of our study, which agreed with findings from a similar study in England, was that when you drink tea you turn on the fat-burning spigot a little bit more than when you drink caffeinated water,” says Physiologist William Rumpler, also of the DHPL.

Sleep
Researchers in Japan have found an amino acid in green tea that could improve slumber in young men, according to a study by Dr Shuichiro Shirakawa, a professor at The National Center of Neurology and Psychiatry in Tokyo. It is the first human study to show that L-theanine (an amino acid found in green tea), can enhance the quality of sleep experienced by young subjects. The research built on previous human studies that suggested L-theanine supplementation could foster ‘a relaxed state.’ The test results indicated that all subjects reported a significant absence of exhaustion and a reduced need for sleep when given the L-theanine, compared to the placebo.

Green Tea’s Cancer-Fighting Target Found
WebMD, March 15, 2004

Antioxidant Slows Tumor Growth
A powerful antioxidant found in green tea may be responsible for the beverage’s heralded anticancer benefits. New research shows that the antioxidant, known as EGCG, binds to a protein found on tumor cells and dramatically slows their growth. Researchers say previous studies have shown that green tea helps protect against a variety of cancers, such as lung, prostate, and breast, but the mechanisms for these effects are not known.

In the study, published in the April issue of Nature Structural & Molecular Biology, researchers identified a potential target for the antitumor action of EGCG on human lung cancer cells that inhibited the cancer cells’ growth. By learning more about this target, researchers may be able to develop new treatments that maximize green tea’s cancer-fighting potential.

Explaining Green Tea’s Anticancer Benefits
In order to better understand how the antioxidants found in green tea may protect against cancer, researchers looked at how they affected a protein found on the surface of cancer cells called laminin receptor. The study showed that when cancer cells with this protein were treated with polyphenol EGCG, the growth of the tumor cells was significantly reduced.

Researchers say the concentration of the antioxidant required to produce these anticancer effects was equivalent to those found in the body after drinking only two to three cups of green tea. Researchers say the results further the understanding of how antioxidants interact with cancer cells and may one day lead to more effective cancer therapies that use green tea as a dietary cancer treatment.

Black tea may lower heart disease risks
PakTribune, 23 Feb 2004
ISLAMABAD: That tea bag soaking in your cup could be brewing up a longer, healthier life, researchers report. A study of over 3,400 adults in Saudi Arabia–a country of tea-lovers–found that those who drank more than 6 cups per day of the brown beverage had a more than 50% lower risk of coronary heart disease compared to tea abstainers, even after adjusting for other factors such as smoking, diet and obesity.

Antioxidants called flavonoids, found in both green and black teas, are thought to be potent weapons in the fight against heart disease. “Tea, the most widely consumed beverage in the world, is a rich source of (these) antioxidants,” explain researchers led by Dr. Iman A. Hakim of the University of Arizona in Tucson. They published their findings in the January issue of the journal Preventive Medicine.

Numerous studies have trumpeted the cardiovascular benefits of green tea, which is the beverage of choice in much of the Far East. But elsewhere in the world black tea reigns supreme, and fewer studies have examined its heart-healthy properties.

The researchers interviewed 3,430 Saudis ranging in age from 30 to 70. Study participants were quizzed on their dietary habits, history of smoking, coffee drinking, exercise and other factors. Just over 6% were diagnosed with coronary heart disease. Tea-drinking is a very social event in Saudi Arabia, and about 90% of those interviewed drank the beverage daily. Comparing heavy drinkers to non-drinkers, the researchers found that those who consumed more than 6 cups of tea per day (about 20% of those interviewed) had a 50% lower risk of heart disease than those who did not drink tea. In general, individuals with heart disease tended to drink less tea than healthier individuals–3.5 cups/day versus 4.5 cups/days, respectively.

How might tea drinking boost heart health? Studies have suggested that flavonoids in tea may lower blood pressure and reduce stroke risk by about 12% for those drinking 3 cups of tea per day. Flavonoids may also lower clotting risks and “hardening of the arteries,” and reduce levels of LDL or “bad” cholesterol, the researchers suggest.

Whatever the reason, tea for two–or more–may be just the ticket for healthy tickers, the researchers conclude. “These findings support a potential protective effect of tea consumption in relation to coronary heart disease,” they say.

Tea’s Health Benefits
The WBAL Channel.com, 23 Feb 2004
Tea has been linked with many health benefits in the last several years because of the antioxidants it contains. All varieties of tea come from the leaves of a single plant, Camellia sinensis. This evergreen contains some of the most powerful antioxidants known.

What can tea do for you?

Heart Disease – Several studies have found tea to be heart healthy. Tea is a rich source of dietary flavonoids, which have been shown to have a protective effect against heart disease. A Dutch study published in an April 2002 issue of the American Journal of Clinical Nutrition found that tea drinkers had a substantially lower risk of heart attacks than nondrinkers.

Heavy tea drinking could also reduce the risk of dying after a heart attack, according to a study published in a May 2002 issue of the journal Circulation. “The greatest benefits of tea consumption have been found among patients who already have cardiovascular disease,” said Dr. Kenneth Mukamal, the study’s lead author.

Another study found that the average cup of tea brewed for two minutes contains about 172 milligrams of flavonoids. Drinking one cup could be expected to cause an immediate positive effect and about 3.5 cups could possibly produce a continuing effect.

Cancer – Could tea really act as a cancer-prevention measure? Tea drinkers in a study conducted in Shanghai, China, were about half as likely to develop cancer of the stomach or esophagus as non-tea drinkers. The results of the study were presented to an April 2002 meeting of the American Association for Cancer Research. The researchers found that people in which certain chemicals, called polyphenols, were present had a lower risk of gastric and esophageal cancer.

Green tea contains the most helpful polyphenols, followed by oolong and black teas. Read more about the study. An Oregon scientist found that white tea, too, may help prevent cancer. “He found that the white tea he gave to mice, it prevented formation of cancerous polyps. The other interesting thing about white tea is that it has the highest amount of antioxidants of any tea beverage in the world,” said tea expert Kyle Stewart.

Dental Health – Surveys have found that people who drink tea may have fewer cavities than those who don’t. This is attributed to the high levels of fluoride in tea plants. Also, components of tea such as catechins, caffeine and tocopherol have been shown to be effective in increasing the acid resistance of tooth enamel. And flavonoids — mainly catechins — have been shown to inhibit bacterial growth on teeth.

Stroke – The flavonoids in tea may also protect against stroke. A 1996 study published in the Archives of Internal Medicine found that men aged 50-69 who drank 4-5 cups of tea a day had a 69 percent reduced risk of stroke.

Rheumatoid Arthritis – According to a study published in the January 2002 issue of the journal Arthritis & Rheumatism, women who drank three or more cups of tea each day were less likely to develop arthritis than those who didn’t drink tea. The study didn’t indicate what kind of tea.

Weight Loss – Green tea may be able to help dieters. In November 1999, the American Journal of Clinical Nutrition published the results of a study at the University of Geneva in Switzerland, in which researchers found that men who were given a combination of caffeine and green tea extract burned more calories than those given only caffeine or a placebo.

For a Health Boost from Tea, Experts And Studies Say Drink Up
iVillage Good Housekeeping, 16 Feb 2004
How much tea drinking does it take to make the most of this beverage’s possible health benefits? John Weisburger drinks about eight cups of tea a day and recommends that everybody do the same. As one of the country’s leading researchers on tea and health – working at the Institute for Cancer Prevention in Valhalla, N.Y. – Weisburger is convinced tea can help ward off some cancers and certain other chronic ills, so he makes sure he drinks plenty of it.

“People should drink tea all day long. It’s now 2:10 p.m. and I’m on my fourth mug,” Weisburger said. Black tea is Weisburger’s usual choice, but he said both green and black tea have been shown to discourage the formation of cell mutations that can lead to certain cancers.

There is no single, widespread recommendation on amounts of tea to drink for possible health advantage. In assorted studies, various amounts have appeared to have an effect. For example, in one study, cholesterol levels improved in people who drank five cups of black tea a day for three weeks. In another study, heart disease was significantly lower in people who drank three cups a day than in those who drank none.

Studies continue and there is not yet a final word on tea regarding its potential health benefits or how much of it to drink. But research, joined by tea’s status as the most widely consumed beverage in the world after water, indicates it is safe to drink in substantial quantities.