rinking green tea could help in the fight against HIV, research suggests.

rinking green tea could help in the fight against HIV, research suggests.

Scientists found a component called epigallocatechin gallate (EGCG) prevents HIV from binding to immune system cells by getting there first.

Once EGCG has bound to immune system cells there is no room for HIV to take hold in its usual fashion.

However, experts said the joint UK and US work, which appears in the Journal of Allergy and Clinical Immunology, was at a very preliminary stage.

Researcher Professor Mike Williamson, of the University of Sheffield, said: "Our research shows that drinking green tea could reduce the risk of becoming infected by HIV, and could also slow down the spread of HIV.

"It is not a cure, and nor is it a safe way to avoid infection, however, we suggest that it should be used in combination with conventional medicines to improve quality of life for those infected.

"Future research is also currently under way in order to determine how much effect can be expected from different amounts of tea."

More work needed

Keith Alcorn, senior editor of the Aidsmap web service, said tests on animals would be needed before any conclusions could be safely drawn on the potential protective effect of drinking green tea.

"This study only looks at the ability of a chemical in green tea to block HIV binding to human CD4 immune cells in the test tube.

"Many substances shown to prevent HIV infection in the test tube turn out to have little or no effect in real life, so I think there's a long way to go before anyone should rely on green tea to protect against HIV infection."

Lisa Power, head of policy at the HIV charity, Terrence Higgins Trust said: "Condoms keep HIV at bay. Anything that boosts your immune system is beneficial for people with HIV, but green tea can't be a substitute for proper medication and prevention techniques."

Green tea has been linked to a positive effect on a wide range of conditions, including heart disease, cancer and Alzheimer's.

Green Tea May Delay Onset Of Type 1 Diabetes

Green Tea May Delay Onset Of Type 1 Diabetes

Researchers were testing EGCG, green tea's predominant antioxidant, in a laboratory mouse with type 1 diabetes and primary Sjogren's syndrome, which damages moisture-producing glands, causing dry mouth and eyes.

"Our study focused on Sjogren's syndrome, so learning that EGCG also can prevent and delay insulin-dependent type 1 diabetes was a big surprise," says Dr. Stephen Hsu, molecular/cell biologist in the School of Dentistry.

They found it also worked well in their original disease focus.

In the mouse, EGCG reduced the severity and delayed onset of salivary gland damage associated with Sjogren's syndrome, which has no known cure.

"EGCG modulates several important genes, so it suppresses the abnormality at the molecular level in the salivary gland. It also significantly lowered the serum autoantibodies, reducing the severity of Sjogren's syndrome-like symptoms," Dr. Hsu says. Autoantibodies are antibodies the body makes against itself.

Both type 1 diabetes and Sjogren's syndrome are autoimmune diseases, which cause the body to attack itself. Autoimmune disorders are the third most common group of diseases in the United States and affect about 8 percent of the population, says Dr. Hsu. Sjogren's syndrome can occur alone or secondary to another autoimmune disease, such as lupus, rheumatoid arthritis or type 1 diabetes.

The study, published in the Oct. 24 issue of Life Sciences, supports earlier research showing EGCG's impact on helping prevent autoimmune disease.

Researchers treated a control group of mice with water and a test group with a purified form of EGCG dissolved in the drinking water. At 16 weeks, the EGCG-fed mice were 6.1 times more likely to be diabetes-free than the water-fed group, and 4.2 times more likely at 22 weeks.

"Previous studies used another animal model that developed type 1 diabetes only after an injected chemical killed the insulin-producing cells. That may not accurately resemble disease development in humans, because type 1 diabetes is a genetic disease," says Dr. Hsu, the study's corresponding author.

"Our study is significant because we used a mouse model with the genetic defects that cause symptoms similar to human type 1 diabetes and Sjogren's syndrome, so the immune cells attack the pancreas and salivary glands until they are no longer functional."

Another related finding was that even when salivary cells were under attack, they seemed to be rapidly reproducing in the control group. The proliferation was suppressed in the EGCG-fed group.

"It's kind of counterintuitive – why would there be proliferation of the glandular cells occurring when the present cells are not secreting saliva?" says Dr. Kevin Gillespie, first author of the study he conducted for his master's research project at MCG.

The proliferation phenomenon also can be observed in psoriasis, an autoimmune disease affecting the skin and joints, says Dr. Hsu. "Normal skin cells turn over every 30 days or so, but skin cells with psoriasis turn over every two or three days." Dr. Hsu's group previously found that green tea polyphenols, including EGCG, inhibited rapid proliferation in an animal model for human psoriasis.

"We never thought proliferation was going on to this extent in the salivary gland, but we now believe it is tightly associated with Sjogren's syndrome," he says.

The next step is to observe Sjogren's syndrome in human salivary gland samples to determine whether the study findings hold up in humans.

"If the abnormal expression of these genes is the same in humans as in the animal model, then the second stage will be intervention and treatment with a pure form of EGCG," says Dr. Hsu.

"The benefit of using green tea in preventing or slowing these autoimmune diseases is that it's natural and not known to harm the body," says Dr. Gillespie, periodontics chief resident at Fort Gordon's Tingay Dental Clinic. "EGCG doesn't have the negative side-effects that can be associated with steroids or other medications that could otherwise be prescribed."

The Miracle of Green Tea

The Miracle of Green Tea

Is any other food or drink reported to have as many health benefits as green tea? The Chinese have known about the medicinal benefits of green tea since ancient times, using it to treat everything from headaches to depression. In her book Green Tea: The Natural Secret for a Healthier Life, Nadine Taylor states that green tea has been used as a medicine in China for at least 4,000 years.

Today, scientific research in both Asia and the west is providing hard evidence for the health benefits long associated with drinking green tea. For example, in 1994 the Journal of the National Cancer Institute published the results of an epidemiological study indicating that drinking green tea reduced the risk of esophageal cancer in Chinese men and women by nearly sixty percent. University of Purdue researchers recently concluded that a compound in green tea inhibits the growth of cancer cells. There is also research indicating that drinking green tea lowers total cholesterol levels, as well as improving the ratio of good (HDL) cholesterol to bad (LDL) cholesterol.

To sum up, here are just a few medical conditions in which drinking green tea is reputed to be helpful:

• cancer
• rheumatoid arthritis
• high cholesterol levels
• cariovascular disease
• infection

• impaired immune function

What makes green tea so special?

The secret of green tea lies in the fact it is rich in catechin polyphenols, particularly epigallocatechin gallate (EGCG). EGCG is a powerful anti-oxidant: besides inhibiting the growth of cancer cells, it kills cancer cells without harming healthy tissue. It has also been effective in lowering LDL cholesterol levels, and inhibiting the abnormal formation of blood clots. The latter takes on added importance when you consider that thrombosis (the formation of abnormal blood clots) is the leading cause of heart attacks and stroke.

Links are being made between the effects of drinking green tea and the "French Paradox." For years, researchers were puzzled by the fact that, despite consuming a diet rich in fat, the French have a lower incidence of heart disease than Americans. The answer was found to lie in red wine, which contains resveratrol, a polyphenol that limits the negative effects of smoking and a fatty diet. In a 1997 study, researchers from the University of Kansas determined that EGCG is twice as powerful as resveratrol, which may explain why the rate of heart disease among Japanese men is quite low, even though approximately seventy-five percent are smokers.

Why don't other Chinese teas have similar health-giving properties? Green, oolong, and black teas all come from the leaves of the Camellia sinensis plant. What sets green tea apart is the way it is processed. Green tea leaves are steamed, which prevents the EGCG compound from being oxidized. By contrast, black and oolong tea leaves are made from fermented leaves, which results in the EGCG being converted into other compounds that are not nearly as effective in preventing and fighting various diseases.

Other Benefits

New evidence is emerging that green tea can even help dieters. In November, 1999, the American Journal of Clinical Nutrition published the results of a study at the University of Geneva in Switzerland. 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.

Green tea can even help prevent tooth decay! Just as its bacteria-destroying abilities can help prevent food poisoning, it can also kill the bacteria that causes dental plaque. Meanwhile, skin preparations containing green tea - from deodorants to creams - are starting to appear on the market.

Harmful Effects?

To date, the only negative side effect reported from drinking green tea is insomnia due to the fact that it contains caffeine. However, green tea contains less caffeine than coffee: there are approximately thirty to sixty mg. of caffeine in six - eight ounces of tea, compared to over one-hundred mg. in eight ounces of coffee.

Drinking Very Hot Tea Can Increase The Risk Of Throat Cancer

Drinking Very Hot Tea Can Increase The Risk Of Throat Cancer

The study was carried out in northern Iran, where large amounts of hot tea are drunk every day.

But an accompanying editorial says these findings are not cause for alarm and the general advice is to allow foods and beverages to cool a little before swallowing.

Cancers of the oesophagus kill more than 500,000 people worldwide each year and oesophageal squamous cell carcinoma (OSCC) is the commonest type. In Europe and America, it is mainly caused by tobacco and alcohol use and is more common in men than in women, but drinking hot beverages is also thought to be a risk factor.

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, so researchers set out to investigate a possible link between tea drinking habits and risk of OSCC.

They studied tea drinking habits among 300 people diagnosed with OSCC and a matched group of 571 healthy controls from the same area. Nearly all participants drank black tea regularly, with an average volume consumed of over one litre a day.

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

Likewise, compared with drinking tea four or more minutes after being poured, drinking tea less than two minutes after pouring was associated with a five-fold higher risk.

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

To minimise errors between reported and actual tea temperatures, the researchers then measured the actual temperature that tea was consumed by nearly 50,000 residents of the same area. This ranged from less than 60°C to more than 70°C and there was a moderate agreement between reported tea drinking temperature and actual temperature measurements.

Our results show a strong increase in the risk of oesophageal squamous cell carcinoma associated with drinking hot or very hot tea, say the authors.

Previous studies from the United Kingdom have reported an average temperature preference of 56-60°C among healthy populations.

They suggest that informing the population about the hazards of drinking hot tea may be helpful in reducing the incidence of oesophageal cancer in Golestan and in other high risk populations where similar habits are prevalent.

These results provide persuasive evidence that drinking tea at temperatures greater than 70°C markedly increases the risk of oesophageal squamous cell carcinoma, says David Whiteman from the Queensland Institute of Medical Research in Australia in an accompanying editorial.

This report also lends support to the notion that thermal injury may be a cause of epithelial cancers, though he points out that the way in which heat promotes tumour development is not clear and warrants further investigation.

However, he stresses that these findings are not cause for alarm, and they should not reduce public enthusiasm for the time honoured ritual of drinking tea. Instead he suggests waiting at least four minutes before drinking a cup of freshly boiled tea, or more generally allowing foods and beverages to cool from "scalding" to "tolerable" before swallowing.

An accompanying video features interviews with some of the researchers as well as original footage from Iran in the early days of the study.

African Tea Offers Promising Treatment For Type-2 Diabetes

African Tea Offers Promising Treatment For Type-2 Diabetes

The researchers have harvested the ingredients for the tea in Africa, totalling approximately fifty kilos of leaves and three hundred kilos of fruit from the wild nature of Nigeria. Afterwards the tea has been produced exactly as local healers would do so. The recipe is quite simple: boil the leaves, young stalks and fruit and filter the liquid.

First mice, then humans

Associate professor Per Mølgaard and postdoc Joan Campbell-Tofte from the Department of Medicinal Chemistry have previously tested the tea on genetically diabetic mice. The results of the tests showed that after six weeks of daily treatment with the African tea, combined with a low-fat diet, resulted in changes in the combination and amount of fat in the animals' eyes and protection of the fragile pancreas of the mice.

The researchers have recently completed a four month long clinical test on 23 patients with type-2 diabetes and are more than satisfied with the result.

"The research subjects drank 750ml of tea each day. The [tea] appears to differentiate itself from other current type-2 diabetes treatments because the tea does not initially affect the sugar content of the blood. But after four months of treatment with tea we can, however, see a significant increase in glucose tolerance," said postdoc Joan Campbell-Tofte from the University of Copenhagen.

Changes in fatty acid composition

The clinical tests show another pattern in the changes in fatty acid composition with the patients treated in comparison with the placebo group.

"In the patient group who drank the tea, the number of polyunsaturated fatty acids increased. That is good for the body's cells because the polyunsaturated fat causes the cell membranes to be more permeable, which results in the cells absorbing glucose better from the blood," said Joan Campbell-Tofte.

The researchers hope that new clinical tests and scientific experiments in the future will result in a new treatment for type-2 diabetics.

Green, Black Tea Can Reduce Stroke Risk, Research Suggests

Green, Black Tea Can Reduce Stroke Risk, Research Suggests

The UCLA researchers conducted an evidence-based review of all human observational studies on stroke and tea consumption found in the PubMed and Web of Science archives. They found nine studies describing 4,378 strokes among nearly 195,000 individuals, according to lead author Lenore Arab, a professor of medicine in the division of general internal medicine and health services research at the David Geffen School of Medicine at UCLA.

"What we saw was that there was a consistency of effect of appreciable magnitude," said Arab, who is also a professor of biological chemistry. "By drinking three cups of tea a day, the risk of a stroke was reduced by 21 percent. It didn't matter if it was green or black tea."

And extrapolating from the data, the effect appears to be linear, Arab said. For instance, if one drinks three cups a day, the risk falls by 21 percent; follow that with another three cups and the risk drops another 21 percent.

This effect was found in tea made from the plant Camellia sinensis, not from herbal teas.

There are very few known ways to reduce the risk of stroke, Arab said. And developing medications for stroke victims is particularly challenging, given that the drug has to get to the stroke-damaged site quickly because damage occurs so fast. Arab said that by the time a stroke victim gets medical care, it's nearly too late to impede the damage.

"That's why these findings are so exciting," she said. "If we can find a way to prevent the stroke, or prevent the damage, that is simple and not toxic, that would be a great advance."

Though no one is certain which compounds in tea are responsible for this effect, researchers have speculated that the antioxidant epigallocatechin gallate (EGCG) or the amino acid theanine may be what helps. Antioxidants are believed to help prevent coronary artery disease.

"And we do know that theanine is nearly 100-percent absorbed," Arab said. "It gets across the blood-brain barrier and it looks a lot like a molecule that's very similar to glutamate, and glutamate release is associated with stroke.

"It could be that theanine and glutamate compete for the glutamate receptor in the brain," she added.

Although a randomized clinical trial is needed to confirm this effect, the findings suggest that drinking three cups of green or black tea a day could help prevent an ischemic stroke.

The study results, published in the online edition of Stroke: Journal of the American Heart Association, were presented Feb. 19 at the American Heart Association's annual International Stroke Conference in San Diego, Calif.

Study co-authors with Arab are Weiqing Liu, a senior statistician in the UCLA Department of Biomathematics, and David Elashoff, associate professor of medicine in the division of general internal medicine and health services search at the David Geffen School of Medicine at UCLA.

The Unilever Lipton Institute of Tea funded this study.

Green Tea Blocks Benefits Of Cancer Drug

Green Tea Blocks Benefits Of Cancer Drug

The study, which found that a component of green tea extract (GTE) called EGCG destroys any anticancer activity of the drug Velcade in tumor-bearing mice, will be published in the journal Blood.

"Our finding that GTE or EGCG blocked the therapeutic action of Velcade was completely unexpected," says lead author Axel H. Schönthal, PhD, associate professor in the Department of Microbiology and Immunology at the Keck School of Medicine of USC. "Our hypothesis was that GTE or EGCG would enhance the anti-tumor effects of Velcade, and that a combination of GTE with Velcade (or EGCG with Velcade) would turn out to be a superior cancer treatment as compared to treatment with Velcade alone."

Herbal remedies, including green tea, have become a popular remedy for cancer patients dealing with side effects of chemotherapy. However, these supplements are unregulated and, for most, their beneficial and/or detrimental effects have not been qualified through research.

Using preclinical models and tumor-bearing mice, the researchers found that the unusually effective blockage of Velcade's therapeutic activity was based on the chemical interaction between molecules. The EGCG molecule and the Velcade molecule were able to form chemical bonds, meaning that the Velcade molecule could no longer bind to its intended target inside the tumor cells.

Clincal trials to verify these results in humans would be highly unethical to conduct, because of the predictably unfavorable outcome. Nevertheless, the researchers expect the results of the study to be applicable to cancer patients.

"The most immediate conclusion from our study is the strong advice that patients undergoing cancer therapy with Velcade must avoid green tea, and in particular all of its concentrated products that are freely available from health food stores," says Schönthal. "It is important to spread this message to health care providers who administer Velcade to patients."

Schönthal points out that for patients on Velcade, supplementing with green tea products should reduce the burden of harsh side effects—which might be attractive to the patient, but comes at a high cost.

"Essentially, in addition to not being able to attack tumor cells, Velcade would be unable to cause side effects either," he says. "As a result, the patient would feel a lot better and conclude that the consumption of GTE helped cope with side effects—while in reality, Velcade simply wasn't active in the first place."

The research findings are part of a larger project run by the team called "Yin-Yang Properties of Green Tea Extract in Combination Cancer Chemotherapy: From Encouragingly Beneficial to Dangerously Detrimental."

"Obviously, the combination of GTE or EGCG with Velcade is an example of 'dangerously detrimental,' "Schönthal says. "But we are also studying another well-established chemotherapeutic drug, where the inclusion of EGCG appears to yield an 'encouragingly beneficial' outcome, which is more in line with our original expectation that GTE should be beneficial, not detrimental."

The study was funded by the Multiple Myeloma Research Foundation.

Drink Brewed Tea To Avoid Tooth Erosion, Study Suggests

Drink Brewed Tea To Avoid Tooth Erosion, Study Suggests

There is a beverage that does not produce such irreversible results. When deciding between the many options available, the best thing to drink to avoid tooth erosion is brewed tea, according to a study in the July/August issue of General Dentistry, the clinical, peer-reviewed journal of the Academy of General Dentistry (AGD).

Apart from tasting good, brewed tea has many health benefits. Tea is loaded with natural antioxidants, which are thought to decrease incidence of cancer, cardiovascular disease, and diabetes.

Mohamed A. Bassiouny, DMD, BDS, MSc, PhD, the lead author of the study, compared green and black tea to soda and orange juice in terms of their short- and long-term erosive effect on human teeth. The study found that the erosive effect of tea was similar to that of water, which has no erosive effect. And, when comparing green versus black, he discovered that there is a better option among those as well.

Dr. Bassiouny says that "when we look at tea and read about the benefits, it's amazing—not because green tea is 'the in thing'—but because there are advantages." He adds that much research done overseas, in countries such as Japan and Europe, found that green tea was identified to being superior over black due to its natural flavonoids (plant nutrients) and antioxidants.

But, if you do drink tea, experts suggest avoiding additives such as milk, lemon, or sugar because they combine with tea's natural flavonoids and decrease the benefits. In addition, stay away from prepackaged iced teas because they contain citric acid and high amounts of sugars. It does not matter whether the tea is warm or cold—as long as it is home brewed without additives.

Kenton Ross, DMD, FAGD, AGD spokesperson, sees patients' erosion problems on a daily basis in his practice. "Severe cases of erosion occur monthly and are frequently associated with high rates of soft drink consumption," he says. "This study clearly shows that brewed teas resulted in dramatically less enamel loss than soft drinks and acidic juices," says Dr. Ross. "I would highly recommend patients choose tea as an alternative to more erosive drinks like soda and fruit juice."

Tips to decrease erosion:

• Reduce or eliminate carbonated beverages. Instead, drink water, milk, or tea
• Skip the additives such as sugar, lemon, and milk
• Drink acidic drinks quickly and through a straw
• Chew sugar-free gum to increase saliva flow in your mouth
• Rinse with water to neutralize the acids, and wait an hour before brushing

Benefits Of Green Tea In Reducing An Important Risk Factor For Heart Disease

Benefits Of Green Tea In Reducing An Important Risk Factor For Heart Disease

The study, performed by Dr Nikolaos Alexopoulos and colleagues at the 1st Cardiology Department, Athens Medical School in Greece, was a randomised trial involving the diameter measurement (dilatation) of the brachial artery of healthy volunteers on three separate occasions - after taking green tea, caffeine, and hot water (for a placebo effect). The measurements were taken at 30, 90 and 120 minutes after consumption. Dilatation of the brachial artery as a result of increased blood flow (following a brief period of ischaemia of the upper limb) is related to endothelial function and is known to be an independent predictor of cardiovascular risk.¹

Results showed that endothelium-dependent brachial artery dilatation increased significantly after drinking green tea, with a peak increase of 3.9 per cent 30 minutes after consumption. The effect of caffeine consumption (or hot water) was not significant.

While black tea has been associated with improved short and long-term endothelial performance, this is the first time that green tea has been shown to have a short-term beneficial effect on the large arteries. Another study has already shown that green tea reverses endothelial dysfunction in smokers.

Green tea, which originates in China but is now consumed throughout the world, is made with pure leaves, and has undergone little oxidisation during processing. The cardiovascular benefits of all teas - as well as dark chocolate and red wine - are attributed to the flavonoids they contain and their antioxidant activity.² However, says investigator Dr Charalambos Vlachopoulos, flavonoids in green tea are probably more potent antioxidants than in black tea because there has been no oxidisation.

"These findings have important clinical implications," says Dr Vlachopoulos. "Tea consumption has been associated with reduced cardiovascular morbidity and mortality in several studies. Green tea is consumed less in the Western world than black tea, but it could be more beneficial because of the way it seems to improve endothelial function. In this same context, recent studies have also shown potent anticarcinogenic effects of green tea, attributed to its antioxidant properties."

Notes

1. The study measured flow-mediated dilatation of the brachial artery, which is predominantly dependent on the release of nitric oxide from the endothelium and represents a well accepted estimate of endothelial function. Measurement of the brachial arteries was performed by high-resolution ultrasound.
2. Flavonoids are naturally found in many plants and have been shown to have many different biological effects in humans. Their antioxidant effects have been found in red wine, red grapes and dark chocolate. Oxidative stress, which has been associated with many human diseases, can be reversed by antioxidant intake.

Drink Green Tea For Healthy Teeth And Gums

Drink Green Tea For Healthy Teeth And Gums

A study recently published in the Journal of Periodontology, uncovered yet another benefit of green tea consumption. Researchers found that routine intake of green tea may also help promote healthy teeth and gums. The study analyzed the periodontal health of 940 men, and found that those who regularly drank green tea had superior periodontal health than subjects that consumed less green tea.

"It has been long speculated that green tea possesses a host of health benefits," said study author Dr. Yoshihiro Shimazaki of Kyushu University in Fukuoka, Japan. "And since many of us enjoy green tea on a regular basis, my colleagues and I were eager to investigate the impact of green tea consumption on periodontal health, especially considering the escalating emphasis on the connection between periodontal health and overall health."

Male participants aged 49 through 59 were examined on three indicators of periodontal disease: periodontal pocket depth (PD), clinical attachment loss (CAL) of gum tissue, and bleeding on probing (BOP) of the gum tissue. Researchers observed that for every one cup of green tea consumed per day, there was a decrease in all three indicators, therefore signifying a lower instance of periodontal disease in those subjects who regularly drank green tea.

Green tea's ability to help reduce symptoms of periodontal disease may be due to the presence of the antioxidant catechin. Previous research has demonstrated antioxidants' ability to reduce inflammation in the body, and the indicators of periodontal disease measured in this study, PD, CAL and BOP, suggest the existence of an inflammatory response to periodontal bacteria in the mouth. By interfering with the body's inflammatory response to periodontal bacteria, green tea may actually help promote periodontal health, and ward off further disease. Periodontal disease is a chronic inflammatory disease that affects the gums and bone supporting the teeth, and has been associated with the progression of other diseases such as cardiovascular disease and diabetes.

"Periodontists believe that maintaining healthy gums is absolutely critical to maintaining a healthy body," says Dr. David Cochran, DDS, PhD, President of the AAP and Chair of the Department of Periodontics at the University of Texas Health Science Center at San Antonio. "That is why it is so important to find simple ways to boost periodontal health, such as regularly drinking green tea – something already known to possess certain health-related benefits."