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Black
Tea and Cancer
There’s a good amount of evidence linking green tea
to a lower risk of certain types of cancer. But does the same hold true
for black tea? The results of clinical trials and population studies
suggest that the answer is yes. For example:
Rectal cancer
A study of nearly 1,000 Russian women found that those who drank at
least 2.5 cups of black tea per day were 60 percent less likely to develop
rectal cancer than those who drank 1.2 cups per day.1
Colon cancer
Based on a follow-up of a nationwide study, researchers concluded that tea
drinkers had a 42 percent reduction in colon cancer risk compared to non-tea
drinkers. That figure increased to a 70 percent reduction in risk in men who
drank more than 1.5 cups of tea per day.2
Cancers of upper digestive tract, colon, rectum,
urinary tract
A survey of 35, 369 postmenopausal women found that among those who
drank two or more cups of non-herbal (i.e. black or green) tea per day, cancers
of the upper digestive tract colon and rectum decreased by 32 percent and cancer
of the urinary tract decreased by 60 percent. And those who drank four or more
cups showed a 60 percent reduction in all of these cancers.3
Skin cancer
Consuming tea regularly at some point in life has been associated with a
significantly lower risk of developing a specific form of skin cancer called
squamous cell carcinoma. This is especially true among long-term tea drinkers
(at least 47 years of consumption) and those consuming 2 or more cups per day.4
Breast cancer
In a study of tea and breast cancer, mice with induced breast cancer that
received black tea theaflavins or green tea catechins in their drinking water
over the course of their lifetimes survived longer and had smaller tumors than
those receiving plain water. 5 Tumor levels were reduced 63 percent
by the theaflavins and 78 percent by the catechins.
Why should black tea help fight cancer? Studies show that
its theaflavins can help ward off free radical damage, slow the uncontrolled
growth of cells, and promote cancer cell “suicide.” Plus, a study of tea and
immunity showed that people who drank five cups of black tea each day for two to
four weeks secreted as much as four times more interferon, a crucial part
of the body’s immune response.6
So as long as the beverage comes from the Camellia
sinensis bush, it looks like it can do plenty of good things for your
health!
1
Dora I, Arab L, Martinchi A, et al. Black tea consumption and risk of rectal
cancer in Moscow population. Ann Epidemiol 2003;13(6):405-11.
2Su
LJ, Arab L. Tea consumption and the reduced risk of colon cancer – results from
a national prospective cohort study. Public Health Nutr 2002;5(3):419-25.
3Zheng
W, Doyle TJ, Kushi LH, et al. Tea consumption and cancer incidence in a
prospective cohort study of postmenopausal women. Am J Epidemiol
1996;144(2): 175-82.
4Rees
JR, Stukel TA, Perry AE, et al. Tea consumption and basal cell and squamous cell
skin cancer: results of a case-control study. J Am Acad Dermatol
2007;56(5):781-85.
5Kaur
S, Greaves P, Cook DN, et al. Breast cancer prevention by green tea catechins
and black tea theaflavins in the C3(1) SV40 T, t antigen transgenic mouse model
is accompanied by increased apoptosis and a decrease in oxidative DNA adducts.
J Agric Food Chem 2007;55(9):3378-85.
6Kamath
AB, Wan L, Das H, et al. Antigens in tea-beverage prime human Vgamma 2Vdelta 2 T
cells in vitro and in vivo for memory and nonmemory antibacterial cytokine
responses. Proc Natl Acad Sci USA 2003;100(10):6009-14.
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Nadine Taylor, M.S., R.D. presents
GreenTeaLibrary.com, the most
comprehensive collection of scientific information describing the
health benefits of green tea.
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