By Michelle Quigley
The Health Benefits of
- China and India share the credit for the
discovery of tea almost 5 thousand years ago.
- It was introduced to the West by Turkish
traders in the 6th century.
- The tea shrub is a perennial evergreen that
grows in many areas of the world in a variety of climates. Growth
depends on acidic soil (pH 4-5.6).
- There are 4 major types of tea. The most
widely consumed and best known are green (nonfermented) and
black(fermented) tea. Red, also known as oolong, and yellow tea,
both partially fermented, are less popular.
- There are two main active ingredients in tea:
- Upon ingestion,
can be easily detected throughout the human
or animal body. It is believed that they exert their actions
directly at the tissue and cellular level rather than indirectly
through intestinal effects. The benefits associated with
polyphenols are generally attributed to their antioxidant activity
and their ability to scavenge free radical oxygen.
- The most abundant
in tea is caffeine.
Caffeine exerts its behavioral and other
effects through competitive antagonism at adenosine binding sites.
Caffeine levels, produced in humans by ingestion of a few cups of
tea are sufficient to antagonize adenosine's nervous stimulation
of the vascular system, heart, kidney, and adipose tissue. Serum
levels of non-esterified
free fatty acids are increased by caffeine,
thus suggesting a mechanism by which caffeine can cause heart
Green tea polyphenols have been shown to
protect against chemically induced tumor initiation and promotion
and to protect against the progression of benign tumors to
malignancy in mice. They have also been shown to be
radioprotective against UV-induced carcinogenesis in
Green polyphenols are Antimutagenic and
reduce the occurrence of chromosome aberrations during mutagen
- Atherosclerosis and
Hypertension- It is believed that the
oxidation of low density lipoprotein(LDL) is critical to the
development of atherosclerosis in humans. Tea polyphenols are
known to block test tube oxidation of LDL by copper ions.
Increased green tea consumption, especially more than 10 cups per
day is associated with decreased total serum cholesterol,
decreased LDL and increased HDL(high density lipoprotein). In
addition, the polyphenols in green tea appear to reduce
hypertension in mice, possibly through the sedative action of a
- Infectious Diseases-
The antibacterial activity of tea catechins
is particularly useful for the treatment of diarrheal diseases
like cholera and typhus. Many viruses are adversely affected by
the presence of tea catechins including influenza and even
- Immune Response
Stimulator- A few studies show how green
tea polyphenols affect the immune system. One polyphenol appears
to stimulate B-cell proliferation in mice.
The polyphenolic compounds may protect
teeth from decay by killing bacteria. They may also inhibit the
collagenase activity of bacteria that lodge in fluid below the gum
line and increase the acid resistance of human tooth
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