Groene thee tegen kanker*
Twee recente studies laten zien dat groene thee een krachtig middel is tegen en bij de behandeling van verschillende kankersoorten.
Zo blijkt uit een studie dat het dagelijks drinken van groene thee de kans op eierstokkanker bij vrouwen met 54% kan verminderen. In de andere studie blijkt dat weliswaar in het laboratorium groene thee darmkankercellen aanzet tot celdood.
Studies and Results
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.
(Juni
2008)
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