Green Tea vs Black
This is from Dina Dyer's newsletter
Janet/FL
http://www.dianadyermsrd.com/newsletters/winter2005.htm
IV. Research Updates - Recent articles about the role of green tea and cancer
A. Tea and circulating estrogen levels in postmenopausal Chinese women in Singapore. Wu AH, et al, Carcinogenesis. 2005 Jan 20.
Increased intake of green tea was correlated with reduced levels of plasma estrogen levels in healthy post-menopausal women in Singapore. Of special interest, increased intake of black tea showed statistically increased levels of this same hormone, increasing risk of breast cancer.
B. Molecular and cellular effects of green tea on oral cells of smokers: a pilot study, Schwartz JL, et al, Mol Nutr Food Res. 2005 Jan;49(1):43-51.
A small pilot study that showed drinking 5 cups of green tea daily for 4 weeks reduced the numbers of damaged cells in the mouth that are commonly seen in smokers as high risk indicators of oral cancer.
C. Green tea consumption enhances survival of epithelial ovarian cancer, Zhang M, et al, Int J Cancer. 2004 Nov 10;112(3):465-9.
A prospective study in China showed increased consumption of green tea was associated with increased survival from epithelial ovarian cancer. At the 3-year mark, 77% of the tea drinkers were still alive compared to 48% of the non-tea drinkers. Survival odds were also enhanced related to amount of green tea consumed (i.e., daily versus weekly consumption).
D. Analysis of catechin content of commercial green tea products, Manning J, Roberts J, J Herb Pharmacother. 2003;3(3):19-32.
Analysis of content of various green tea products (capsules and tea bags) for their catechin content (the active ingredient for anti-cancer effects) showed wide variability compared to label claims. All products had significantly lower levels than claimed (9-48%).
(Note: I use loose-leaf green tea when possible, which I purchase at Asian grocery stores or a local specialty shop. Taste is far superior to most bagged green tea. Remember to steep in water that is just below the boiling point for the best flavor. I do drink about 1 quart of green tea daily, either warm or cool.)