Camellia
sinensis, the plant commonly referred to as green tea, has
been the discussed for decades as having health promoting
effects. Green tea contains many different flavinoid compounds.
Flavinoids act as strong antioxidants in your body to neutralize
free radicals. Aside from water, tea is the most widely consumed
beverage in the world. Green tea makes up 20% of the total
tea production.
Green
tea contains about 10mg of caffeine per cup. Decaffeinated
green tea is not recommended because of the process used to
extract the caffeine from the tea leaves. Most common is solvent
extraction where chemicals known as solvents are used to extract
the caffeine causing the tea to become contaminated with the
solvents.
Commonly used for weight loss, green tea helps regulate blood
sugar, and thereby reduces appetite and food cravings. Theanine
an amino acid and a powerful compound extracted from green
tea is now being used for mood disorders and has been shown
to enhance the anti-tumor activity of doxorubicin a common
chemotherapeutic agent. In a recent study published in September
10, 2003 International Journal of Cancer, green tea has been
shown to significantly reduce breast cancer risk in Asian-American
women. There was no risk reduction in women who drank black
tea only.
Most recently
there has been some talk about the effects of green tea on
cancer cells with studies showing a decrease in carcinogenic
activity, decreased risk of prostate cancer, and increased
apoptosis in cancer cells. Another study showed an increase
in sex hormone binding globulin which lowered estradiol levels
and ultimately breast cancer risk. One double-blind placebo
controlled trial conducted on 51 women showed a 69% response
rate in cervical dysplasia when supplemented with green tea
extract orally and applied topically to the cervix as opposed
to 10% response rate in the placebo group.
Green tea has been shown to decrease the growth of streptococcus
in the mouth decreasing plaque formation.
Green tea does contain tannins, which can bind to minerals
and decrease our absorption so it is important to not take
your vitamin and mineral supplements with either coffee or
tea.
The benefits of green tea are seen at higher doses averaging
around four cups a day. For people who just don't like the
taste of green tea I suggest supplementation. Good quality
green tea supplements are highly concentrated and one serving
is the equivalent of 10 cups of tea. I like to suggest to
people who enjoy iced tea to just brew up some iced green
tea at home and take it with them.
Some of
the local tea and coffee shops will make unsweetened green
tea for you. One of the things I have heard people complain
about with tea is the acidity. Drinking green or any tea high
in tannins on an empty stomach can cause nausea. It is important
to eat before enjoying a good cup of tea either hot or iced.
Int
J Cancer 2003;106:574-579.
Modern Phytotherapist 2002 vol 7#1
Prev Med. 1992 May;21(3):334-50.
Eur J Cancer Prev. 2003 Oct;12(5):383-90.
Protective effects of green tea extracts (polyphenon E and
EGCG) on human cervical lesions.WS, Yoo J, Huh SW, Kim CK,
Lee JM, Namkoong SE, Bae SM, Lee IP.
Kuhn, Merrily, Winston, David, Herbal Therapy and Supplements;a
Scientific and Traditional Approach, Lippincott, NY.