In two different studies, one by scientists at the Academy of Preventive Medicine in Beijing, China and the other by James Klaunig at the Indiana University School of Medicine in Indianapolis, the effects of green tea  on oxidative stress, brought on by the toxins of cigarette smoke, were  investigated. Oxidative stress, an imbalance in the  pro-oxidant/antioxidant status of a cell, appears to cause or participate in the development of certain diseases-notably cancer.

Researches found that when cigarette users drank an equivalent of six cups of green tea a day, their bodies suffered 40% to 50% less oxidative  damage. This potentially lowers their risk of cancer, emphysema, heart  disease and other illnesses. Oxidative damage was reduced to that of levels found in nonsmokers prior to drinking green tea. However, it is important to note that those who drink green tea and continue to smoke are still raising their risk of experiencing oxidative damage.  Nonsmokers who were studied exhibited significant decreases in oxidative damage as well.

GREEN TEA MAY PREVENT ORAL CANCER 

At a symposium in Washington DC, 1998, a team of Chinese scientists, Ning Li from the Institute of Nutrition and Food Hygiene, Zheng Sun from the Chinese Academy of Preventive Medicine and Junshi Chen from the Beijing Dental Hospital, revealed that drinking green tea improves pre-cancerous conditions of oral leukoplakia in patients and suggests it may have certain preventive effects in oral cancer.

The study involved 32 patients, 20 males and 12 females, 23-28 years of age with oral mucosa leukoplakia, a pre-cancerous lesion of oral cancer. During a six month period, patients drank three cups of green tea a day and applied a mixture of green tea and glycerin directly to the lesion. As a result, 38% of the patients experienced a reduction in the size of a single lesion or in the total size of multiple lesion by 30% or more. 59% saw no changes at all. At the same time, the frequency and rate of formation of cancerous cells decreased significantly.

Although the sample size and the time of treatment of this study are limited, the results provide encouraging and direct evidence on the preventive effects of green tea on human cancer.

GREEN TEA MAY PREVENT RHEUMATOID ARTHRITIS 

Medical researchers at Case Western Reserve University in Cleveland, published a study in April, 1999 reporting that drinking four or more cups of green tea a day may prevent rheumatoid arthritis and reduce the severity of it in those who are currently battling the disease.

The study was conducted on mice with collagen induced arthritis, which is similar to that of rheumatoid arthritis in humans. The mice that received green tea were less likely to develop arthritis than the mice who received plain drinking water. However, the mice that received green tea and yet still developed arthritis had less severe forms of arthritis.

It was concluded that the antioxidants present in green tea possess not only cancer-preventeing properties but also anti-inflammatory properties. Rheumatoid arthritis is an inflammatory disease that causes pain, swelling, stiffness, and loss of function in the joints. The  antioxidants in green tea may prevent or reduce the severity of these  symptoms.

Although further research is needed in this area, the study closely mimics the human disease of Rheumatoid arthritis and provides encouraging evidence on the preventive effects of green tea on
Rheumatoid arthritis.

GREEN TEA AS CANCER PREVENTIVE 

Continuing research on the beneficial properties of green tea to human health has produced several new findings. Most notable is a study by Japanese scientists of the Saitama Cancer Research Institute relating the delay of cancer onset with the consumption of green tea. The study  shows that early stage breast cancer spreads less rapidly in women with  a history of drinking five or more cups of green tea a day. As a result,  there is a lower recurrence rate and a longer disease-free period.

With the evidence that green tea and EGCG, a catechin found only in green tea, are a natural and readily available inhibitor of TNF-, a gene expression which promotes the growth in cancer cells and in their surrounding tissue, it is possible for researchers to extend this idea to other various human diseases. Since EGCG has also been proven to kill cultured cancer cells without causing harm to surrounding healthy cells, green tea could be beneficial not only for cancer prevention but also in
the therapy and prevention of other diseases.