Drink to your health

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Drink to your health

JoAnn Guest

Nov 05, 2006 18:55 PST

 

 

DR. T.S. SARAVANAN

http://www.hindu.com/mag/2006/11/05/stories/2006110500160600.htm

 

Catechins in green tea are novel biocompounds with multifarious

health benefits.

 

Protective effects: Preparing green tea in Japan.

 

GREEN tea is a perennial shrub belonging to the family Camellia,

native to the mountainous southwest of China. Teas are usually

categorized into two types: Chinese (Variety Sinensis) and Assam

(Variety Assamica).

All teas come from leaves that are picked and processed from the

same type of tree. The specific method of processing differentiates

the various types of teas into green, black, and oolong tea.

 

In preparing green tea, the leaves are dried but not fermented.

Commercially prepared green tea extracts contain 60 per cent

polyphenols.

 

Good for health

 

There are four primary polyphenols in green tea and they are often

collectively referred to as catechins. As powerful antioxidants,

catechins have been shown in recent studies to fight viruses, slow

aging, antiproliferative effect on cancer cells and also have other

beneficial effect on health.

 

Clinical tests have shown that catechins destroy free radicals and

have far-reaching positive effects on the entire body. The free

radicals are highly reactive molecules that can damage the body at

the cellular level leaving the body susceptible to cancer, heart

disease and many other degenerative diseases.

 

Recent research findings suggest that green tea confers protective

effects against many cancers.

 

The incidence of prostate cancer, for example, is the lowest in

China and Japan, countries with high green tea consumption. Risk of

oesophageal cancer was reduced by 60 per cent in those who consume

two to three cups of green tea daily in China. A prospective cohort

study of 8,552 Japanese found a significant inverse relationship

between green tea consumption and cancer incidence.

 

Females consuming more than 10 cups of green tea daily had the most

notable protection, compared with those consuming less than three

cups per day.

 

Better outcomes

 

Green tea consumption has also been associated with a better outcome

in some with breast cancer. Higher intake of green tea (mean: eight

cups a day) is associated with a significantly reduced recurrence

rate and a longer disease-free period, particularly among pre-

menopausal women with

histologically classified stage I and II breast Cancer. Among the

specific green tea related benefits noted in patients were decreased

numbers of axillary lymph node metastases.

 

Further, Epigallocaechin-3-gallate (EGCG) especially has shown

marked anti-cancer effects against breast, colon, prostate,

pancreatic, skin, bladder, lung, stomach, ovarian, leukaemia and

liver cancer.

 

ECGC has also been shown to induce apoptosis in several of these

cancer types while leaving normal cells unaffected and also shown to

inhibit

urokinase, a proteolytic enzyme often required for cancer growth,

angiogenesis and androgen activity in prostate cell line. Very

recently ECGC has been shown to be more effectively suppress the

growth of

prostate cancer and epithelial ovarian cancer cell lines derived

from tumours of patients with different stage of disease.

 

Heart and cholestrol

 

The incidence of cardiovascular disease in China is about 80 per

cent lower than in developed countries. This has been associated

with the

high consumption of green tea.

 

Numerous epidemiological studies have also associated high intake of

green tea with decreased risk of atherogenesis in Japan.

 

In nitro and animal studies have shown that green tea and its

catechins,

especially EGCG, can help prevent oxidation of LDL-cholesterol.

Recently, a human study demonstrated that EGCG inhibits

phospholipids hydroperoxidation in plasma.

 

Mixed results have been reported on the ability of green tea to

significantly reduce LDL-cholesterol oxidation in humans in that

daily

consumption of seven to eight cups of green tea might reduce

LDL-cholesterol oxidation to an extent reduce the risk of

cardiovascular disease.

 

In Japan, researchers have found that green tea may protect the

ageing brain, as regular consumption means lesser risk of mental

decline due to age.

 

Further, a study of 1003 70-year-old adults revealed that those who

drank two or more cups a day were about half as likely to show

cognitive

impairment as those who drank three cups or less each week. Men and

women who averaged one cup per day fell somewhere in between.

 

Anti-inflammatory

 

In addition, catechins have exhibited a variety of anti-inflammatory

effects, raising hopes that they might be helpful in treating some

forms

of arthritis, dermatosis, gout and other inflammatory conditions.

 

Green tea also has thermogenic properties and promotes fat

oxidation.

There is in vitro evidence that green tea and its catechins have

antiviral and antimicrobial activities.

 

Recently various green tea catechins were shown to inhibit

extracellular release of vero toxin from enterohemorrhagic E. coli.

 

The writer has carried out research on green tea catechins at John

Wayne Cancer Institute at Santa Monica, Los Angeles, California.

 

 

JoAnn Guest

mrsjo-

www.geocities.com/mrsjoguest/Diets