Studies of Green tea's value in maintaining good
health have been conducted and reported in medical
journals around the world.
Green Tea and Cancer
Of particular interest are the studies that indicate
that Green tea helps reduce the risk of cancer.
Experts believe that its powerful antioxidants help to
disarm free radicals (highly relative oxygen compounds
that damage healthy cells), which are believed to
contribute to many degenerative diseases, including
heart disease and cancer. The American Journal of
Epidemiology has reported that a study of 35,369 women
and their incidence of cancer during an eight-year
period linked regular Green tea drinking with a lower
risk of cancers of the upper digestive tract, colon
and rectum. In Britain, positive results have been
attributed to using Green tea to combat tumours of the
colon, pancreas and breast. It is interesting to note
that the amounts of Green tea used were not megadoses;
only about four (4) cups per day!
Published studies in Australia by the CSIRO (here and
here) have confirmed what Chinese and Japanese
scientists, doctors and consumers of Green tea have
known for years - Green tea is good for you! While all
tea is healthy to drink, Green tea (derived from
camellia sinensis) contains the highest level of
polyphenols (flavonoids), which are known for their
antioxidant activity.
Antioxidants
Polyphenols or flavonoids are antioxidants and these
compounds are most prevalent in Green teas
particularly EGCG (epigallocatechin gallate - the most
powerful. EGCG has the ability to block the enzyme
urokinase, which helps tumours grow by attacking
neighbouring cells. EGCG effectively destroys
urokinase s ability to destroy good cells.
Polyphenols' antioxidant ability helps cell DNA to
reproduce itself accurately rather than in a mutated
form, and Chinese medicines from green polyphenols
have long been used to treat nephritis (kidney
disease), hepatitis( liver disease) and even
leukaemia.
Polyphenols scavenge cell damaging free radicals,
which are linked with cancer-causing genes and cause
LDL cholesterol to form artery-clogging plaque. The
polyphenols in tea possess 20 to 30 times the
antioxidant potency of vitamins C and E. Antioxidants
impair the ability of free radical cells to harm the
molecules that make up our bodies.
Antioxidants are known to be beneficial in fighting
certain cancers and reducing the effects of ageing. It
has been proposed that the high consumption of Green
tea in Japan may be one of the positive contributing
factors for low levels of cancer of the prostate in
men and lower levels of breast cancer in women (along
with higher consumption of isoflavones eg tofu, miso &
soy bean products).
These new studies point to evidence that these healing
properties have a scientific basis. Consumption of tea
is being studied for its reported benefits on:
Enhancing immune function
Lowering LDL cholesterol levels (CSIRO research)
Increasing HDL cholesterol levels
Reducing blood pressure
Thinning the blood
Reducing the risk of a heart attack
Lowering the risk of stroke
Reducing the risk of cancer
Boosting longevity
Weight loss - research paper
Aiding digestion
Preventing dental cavities and gingivitis
According to the Chinese herbal classic, the Pentsao,
common black or Green tea has several health benefits.
Properties and Uses: Brightens the eyes, clears the
voice, invigorates the constitution, removes
flatulence, opens the acupuncture meridians, illumines
the spirit, improves the digestion, relieves thirst
and is cooling, diuretic and astringent.
As a digestive aid, tea also has a special solvent
property that cuts the fats and oils from a rich meal.
Green Tea and Heart Disease
British researchers have discovered that four to five
cups of Green tea a day might help reduce both high
cholesterol and high blood pressure. Green tea seems
to work not only in reducing LDL-cholesterol oxidation
but also in lowering overall blood cholesterol levels.
Nutrients
Tea is a dietary source of important vitamins and
minerals. Tea contains Carotene, a precursor to
vitamin A; Thiamine (vitamin B1); Riboflavin (vitamin
B2); Nicotinic acid, Pantothenic acid, Ascorbic acid
(vitamin C) vitamin B6; Folic acid; Manganese,
Potassium, and Fluoride.
ABOUT GREEN TEA
Green Tea and Bad Breath
The Japanese drink Green tea is known to suppress foul
breath caused by certain foods. The deodorising effect
of Green tea leaves has been known for centuries, and
tea leaves traditionally have been used as deodorants.
A study demonstrated the deodorising action of Green
tea polyphenols in a test against methyl mercaptan,
the compound most closely associated with halitosis.
Green tea also has been shown to suppress bad smells
produced by trimethylamine and ammonia.
Sencha (literally, roasted tea) indicates the past
processing methods used to make this most popular of
all Japanese Green tea. Today, sencha is initially
steam treated before further processing with hot air
drying and finally pan-frying. Over three quarters of
all tea now produced in the Japanese tea gardens are
in fact graded as sencha, a tea selected for its
pleasant sharpness and fresh qualities complementing a
leaf of high uniformity and rich emerald colour.
However, the flavour, colour and general quality of
sencha is highly variable, and depends not only on
origin but also season and the leaf processing
practises locally employed. It is well known that
later harvests of sencha have more bitter qualities, a
more robust flavour and generally less aroma.
Furthermore, the leaf of late season teas is generally
less uniform. Most regions make a number of kinds of
sencha, which are named according to the kind of
processing used. Sencha is the tea most likely to be
offered in a Japanese household or restaurant.
Japanese production techniques have centred
exclusively on perfecting and diversifying forms of
Green tea, traditionally showing no interest in the
fermented (black) tea much favoured by the Western tea
drinker. Even so, a remarkable selection of teas is
produced in Japan and much is made of regional and
seasonal variations among the many kinds of Green tea
available, particularly the higher grades of tea.
Early season sencha, the new season tea or shin cha,
are generally regarded as the best of each year's
crop, and different regions compete on quality and
seasonal availability.
GREEN, BLACK and OOLONG
All teas, Black, Green or Oolong, come from the leaves
of the same plant known as the Camellia Sinensis. The
basic difference is that Black Tea originated from
fermenting the leaves while Green Tea is from
unfermented leaves; Oolong is semi-fermented. The
freshly picked Green Tea leaves are steamed to
de-activate enzymes which cause fermentation or
oxidation resulting in the maintenance of its green
color. The process for the Green Tea production,
picking time during the season and the difference in
soil and climate conditions create the different types
of Green Teas. Green Tea powder may also be used as a
cooking additive and for Japanese Tea ceremonies.
HOW TO PREPARE GREEN TEA
Tea vs Toxins
Tea bags can cure "sick building syndrome" say
Japanese researchers. People who move into a new house
can suffer nausea and sore throats due to the
chemicals from fresh paint and glue, with one of the
chief culprits being formaldehyde. Now the Tokyo
Metropolitan Consumer Center has found that unused tea
bags scattered around the house soak up the
formaldehyde, aided by tannin in the tea. They found
that the concentration of formaldehyde in the air fell
by between 60 and 90 percent. Black or Green tea bags
are said to work best.
New Scientist
There are many types of Green tea, yet they all share
one thing in common: NONE are prepared with boiling
water! Any Green tea worthy of the name will turn
bitter if it is brewed at too high a temperature. All
Green teas should be brewed at between 80c and 90c.
Convenient methods for achieving this are: (a) let the
kettle sit for five or so minutes after boiling,
before you pour the water; or (b) first add a dash of
cold water over the dry leaf before adding the freshly
boiled water; (c) take kettle off the boil when you
see whisps of steam coming from the kettle.
There is one other very important point to remember:
NEVER OVER-BREW! Green tea only needs one to two
minutes brewing at most (depending on the type of
Green tea and the personal preference of the tea
drinker).If you leave the Green tea brewing for too
long, it will become bitter. The exception is when
making iced tea - use double the amount of leaf, and
add to cold water two or three hours in advance. Just
before drinking add some ice and a little natural
stevia to taste if sweetness is desired!
Please remember that Green tea leaves can be re-used.
In fact, the Chinese believe that the second infusion
makes a better cup of tea than the first! A good Green
tea will provide at least three infusions. Just bear
in mind when making subsequent infusions leave the
water in contact with the leaf 20 seconds or so longer
each time.
Adapted from www.searchforgoodhealth.com.au