Cup of green tea per day halves the mortality risk of women with ovarian cancer
Women with ovarian cancer who drink a cup of green tea every day are half less likely to die than women who do not drink tea. A team of Chinese and Australian epidemiologists comes to this conclusion in a small study, which appeared in 2004 in the International Journal of Cancer.
The researchers studied a group of 254 Chinese women from the Hangzhou region, which were recently diagnosed with epithelial ovarian cancer. The researchers followed the women for at least three years. They knew the lifestyle of the women, and kept track of which women died and which women survived.
Of the tea drinkers 78 percent of the women was still alive when the study ended. Of the women who did not drink tea 48 percent survived. The women who did not drink tea were almost twice as likely to die during the study than the women who drank green tea.
The women who drank a cup of green tea every day or more often were better protected than women who did not drink green tea every day
Tea drinking habits
Most Chinese drink their tea differently than westerners. This may explain why in Chinese epidemiological studies green tea - black tea is not popular in China - tea has all kinds of positive health effects, whereas western studies are less conclusive.
Chinese people usually do not use tea bags and teapots. They put a few dried leaves in a large cup and pour hot water on them. They don't use milk and sugar. Often they make multiple cups of tea from each serving of leaves, just by pouring fresh hot water on the used tea leaves. This habit may increase the amounts of polyphenols that are released from the tea leaves.
"The anticarcinogenic properties of the polyphenolic compounds present in green tea, including inhibition of proliferation and transformation, have been observed in cell and animal model studies", write the researchers. "The tea component theanine can enhance the antitumor activity of adriamycin and doxorubicin against ovarian sarcoma."
"Progress has been made recently in understanding the molecular mechanisms of cancer chemo-prevention by tea and tea polyphenols. The green tea constituent, epigallocatechin-3-gallate, can induce apoptosis and cell cycle arrest in human carcinoma cells."
"In our study, increasing the consumption of green tea post-diagnosis was associated with an improved survival of ovarian cancer. We conclude that regular consumption of this tasty and inexpensive beverage may provide primary and tertiary prevention of epithelial ovarian cancer. Nevertheless, further studies are needed to confirm our findings."
Int J Cancer. 2004 Nov 10;112(3):465-9.
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Cancer Prevention & Survival