Another Good News on Drinking Green Tea

We've heard of the benefits of green tea but what about the evidence. The scientific community has shown strong interest in uncovering just what the benefits might be. Some have been cautious and say that there is limited long term evidence that green tea can combat certain diseases

(1). However, a recent study (reported on the ScienceDaily site) has found green tea improves the risk factors involved in heart disease

(2). Drinking green tea improves the way cells in the lining of the circulatory system work. These cells are called endothelial and if they are not working well, then atherosclerosis may take hold. So the function of the endothelial cells are an indicator of cardiovascular risk.

A team of researchers at the Athens Medical School (Greece) led by Dr. Nikolaos Alexopoulos conducted a trail where volunteers had their brachial artery measured after consuming green tea, caffeine and hot water. The brachial artery was measured for the amount it had dilated. Dilation occurs when there is an increase in blood flow, and increased blood flow is good news.

Dilation was significant after drinking green tea, while it wasn't after drinking hot water or caffeine. It is known that black tea also impacts positively on endothelial function, but green tea is likely to have stronger antioxidants as it undergoes less oxidisation during processing.

What is positive for us is that antioxidants reverse the effect of oxidisation in the human body. This has to be good for many diseases. In fact another study mentioned in the ScienceDaily report (ibid) showed that damage to the endothelial cells caused by smoking can be reversed by green tea. Overall tea drinking is linked to reduced cardiovascular problems and mortality rates.

Another study, whose researchers were motivated by the value of green tea in oral hygiene, has looked at antibacterial activity in inhibiting bacteria

(3). A bacteria called DNA gyrase locates a site or binds itself to a location. Drugs cannot be used to remove the bacteria because of serious side effects.

A team of researchers at the National Institute of Chemistry in Ljubljana (Slovenia) found that green tea catechins, in particular one known as EGCG (short for epigallocatechin), are able to target the DNA gyrase. The benefit of green tea, according to the lead researcher Roman Jerala, is its safety record as opposed to toxicity associated with drugs

(4). Further related research has found that green tea helps overcome the resistance of certain bacteria to antibiotics. Dr. Mervat Kassem from the Faculty of Pharmacy at Alexandria University in Egypt found that drinking green tea at the same time as taking the antibiotics improved the efficiency of the drugs to kill the bacteria including the strain of superbugs

(5). The antioxidant levels of green tea is reported to be a hundred times that of vitamin C and 25 times that of vitamin E. It is the catechins that are the most effective antioxidants in the tea. If these have the potency to reverse damage to cells, what other effects does green tea have? The cautions showed by some are valid; but they are a little behind given the conclusions of the recent research which has positive news about the benefits of green tea.
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Green Tea Reduce Risk of Ovarian and Colorectal Cancer

Green tea has rapidly entered the American market as a claimed cure and preventative for almost everything that ails mankind. It seems too good to be true, but now we are finding out that it is true. Recent studies reveal green tea's benefits as an antioxidant, promoter of glucose tolerance, protector of the liver and detoxification system, and benefactor of the cardiovascular system. Two recent studies show that green tea is also a powerful agent in the prevention and cure of cancers.

Studies and Results

The March, 2008 issue of Cancer Epidemiology Biomarkers and Prevention, contains a study from the Fred Hutchinson Cancer Research Center in Seattle. In a population based study in Washington state, 781 women with epithelial ovarian cancer diagnosed between 2002 and 2005, and 1,263 controls completed self-administered questionnaires detailing consumption of caffeinated and non-caffeinated coffee, teas, and colas. They also completed in-person interviews regarding reproductive and hormonal exposures.

Researchers assessed risk associated with coffee, tea, and cola drinking and with total caffeine consumption using logistic regression to calculate odds ratios and confidence intervals. Results indicate that neither caffeinated nor decaffeinated coffees were associated with ovarian cancer risk. They also observed no association of total caffeine with risk using a combined index that summed intake from coffee, tea and carbonated soft drinks.

Among teas, neither herbal/decaffeinated nor black teas were associated with risk. However, women who reported drinking green teas had a 54% reduction in risk of ovarian cancer. Associations of green tea with risk were similar when invasive and borderline cases were considered separately and when Asian women were excluded from analysis.

In the second study from Cancer Biology and Therapy, researchers from the Fourth Military Medical University in Xi'an China, reported progress in identifying the underlying mechanism by which green tea possesses therapeutic cancer effects through induction of apoptosis (programmed cell death) in colorectal cancer. Two different lines of colorectal cancer cells were treated with different concentrations of green tea, which led to repression of cell proliferation and induction of apoptosis in both cell lines.

The researchers concluded that the p-53 up-regulated modulator gene plays a critical role in green tea induced apoptosis pathways in colorectal cancer cells. Their demonstration of this effect may be useful in the therapeutic target selection for p53 deficient colorectal cancer.

Additional Implications

The results of these studies suggest that green tea may also be a factor for inducing apoptosis in breast cells and endometrial cells, thereby acting as both a preventative and a factor in the cure for these cancers.

A further implication for the first study may be drawn from its conclusion that the administration of caffeine containing coffee, tea, and colas yielded no association with risk for ovarian cancers.

About Green Tea

According to Phyllis and James Balch in their book Prescription for Nutritional Healing, green tea contains polyphenols, including phytochemicals with antioxidant, antibacterial, antiviral, and other health enhancing properties. Epigalloacatechin gallate (EGCG) is a particular type of polyphenol in green tea that has shown in tests to be able to penetrate the body's cells and shield DNA from the potent free radical, hydrogen peroxide.

In addition to protecting against cancers, green tea lowers cholesterol levels, and reduces the clotting tendency of blood. It shows promise as a weight-loss aid that can promote the burning of fat and the regulation of insulin levels and blood sugar.

Green tea is simply the unprocessed leaves of the tea plant, unlike black tea which is fermented. During processing, much of the polyphenols of black tea are lost.

In addition to brewing and drinking green tea, there are green tea supplements available. Some of these contain the whole plant, while others contain extracts. Whole plant supplements are usually preferable because they are backed by the integrity of the whole plant. Many green tea supplements are standardized to provide a quantifiable amount of EGCG, viewed as its most beneficial component.

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