|Can Green Tea Fight Cancer and Cardiovascular
Although many tea-drinking Americans have grown up on black tea, green tea is
gaining popularity due to its reputation for promoting health. The major
difference between black tea and green tea comes from the way they are produced.
In black tea, the leaves are dried slowly, and during this time the antioxidants
in the leaves disintegrate. In green tea, the leaves are slightly steamed and
then quickly dried, protecting the antioxidants from disintegration. This simple
difference in procedure makes all the difference in health. Antioxidants can be
powerful tools for health, and many people know that vitamins C and E are good
sources of antioxidants. It may not be as well known that the antioxidants in
green tea are of even greater benefit than those in vitamins C and E. Beyond
promoting overall health, the green tea antioxidants have also shown promise for
disease prevention and control.
Recently, two researchers published separate reviews of studies looking at
the relationship between green tea consumption and cancer rates. They determined
that the more green tea a person consumes, the less likely he or she is to get
colon, stomach, bladder, breast, pancreatic, esophageal, prostate, or skin
cancer. However, many of the studies involved single cases and some relied on
information from interviews, which can be subjective. More clinical trials are
needed to establish this relationship.
Other studies seem to indicate that the antioxidants in green tea can lower
cholesterol levels. One study showed that 10 cups a day of green tea was able to
lower cholesterol levels; however, another study of 6 cups a day did not show
these results. Again, more clinical trials are needed.
Most studies on green tea conclude that you need to drink 6 to 10 cups a day
to see health benefits. One cup of green tea contains significantly less
caffeine than coffee. However, when you multiply that amount by 6 to 10 times it
adds up to a lot of caffeine. Since too much caffeine may cause side effects
(such as insomnia, restlessness, headaches, nervousness, and rapid heartbeat),
decaffeinated green tea is recommended. Green tea extracts are also available. A
recommended dose for general health is 300 to 400 mg/day. (Look for a product
that states that it has been standardized to contain 80 percent total
polyphenols and 55 percent epigallocatechin.)
In other places in the world, green tea has been consumed to promote health
and longevity for approximately 5,000 years. Recently, it has gained popularity
in America. The research to date supports consuming green tea for general
health benefits. However, more studies are needed to confirm its specific role
in disease prevention.
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Imai K, Nakachi K. Cross sectional study of effects of drinking green tea on
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polyphenols. Jpn J Clin Oncol. 1993;23(3):186-190.
Weisburger JH. Tea and health: the underlying mechanisms. Proc Soc Exp
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|Review Date: March 2000|
|Reviewed By: Integrative Medicine editorial|
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