Tea is one of the most ancient beverages consumed around the world, with black tea accounting for about 75% of the world’s tea consumption. People in the US, UK and Europe tend to drink much more black tea, while the Japanese and Chinese cultures consume more green tea. Oolong and white tea account for only a fraction of the total amount of tea currently consumed throughout the world. Green teas contain polyphenol compounds which are antioxidants, making them relevant in the fight against cancer. A recent study done in California found that drinking a cup or more a day of green tea could possibly counteract the effect of smoking on lung cancer, and that the antioxidants in green tea could possibly inhibit tumor growth in those who had already been diagnosed with cancer.
Results of Green Tea/Smokers Study
The study evaluated 170 patients with lung cancer as well as 340 health patients, asking each participant to describe their cigarette smoking habits, green tea drinking habits and other lifestyle factors as well, for the past five years. Each participant underwent genotyping to determine whether any of the genotypes associated with cancer were in their body. Overall, the study showed that both the smokers and nonsmokers who did not drink green tea had a five times greater risk of lung cancer compared with those who had at least one cup per day. Among the smokers, those who did not drink green tea at all had a nearly 13 times increased risk of lung cancer as compared to the smokers who drank one cup or more of green tea per day. The bottom line results of this particular study showed that green tea can protect both smokers and non-smokers from lung cancer.
Other Studies Linking Green Tea to Cancer Prevention
Although not yet proven in human studies, many studies done on animals have shown green tea to substantially inhibit tumor growth at different organ sites including the skin, lung, oral cavity, esophagus, stomach, small intestine, colon, liver, pancreas and mammary glands. The human studies done have shown a link between green tea consumption and reduced risk of cancer in the colon, breast, ovary, prostate and lung, however the other factors such as physical activity, weight and lifestyle of patients make the results a bit inconclusive at present. Green tea’s cancer-fighting reputation comes from polyphenols, which are chemicals with high levels of antioxidant properties. Antioxidants protect the cells in your body from free radicals which can lead to the development of cancer. In a study done in 2008, EGCG was added to the drinking water of 10 female mice, with an equal number being given plain water. All twenty mice were injected with breast cancer cells. In the mice who had been given the EGCG, the tumors were a full 66% smaller than those in the untreated mice, and the tumors also appeared to have less blood supply, which suggests that the EGCG inhibits blood supply to cancer cells.
Safety Considerations Regarding Green Tea Consumption
While tea is generally recognized as safe by the FDA, studies have been done on the consumption of up to 1200 mg of EGCG in supplement form, and found adverse reactions such as nausea, heartburn, stomachache, abdominal pain, dizziness, headache and muscle ache were possible. Considering that a very strong-brewed cup of tea will contain a maximum of 180 mg of EGCG, unless you consume substantially more than 5 cups per day, you are probably safe from any negative side effects.
It’s important to recognize that the bottom line is that while there are no definitive answers as yet, there is no harm in adding a few cups of green tea to your daily routine, and it could, possibly protect you from getting cancer as well as lowering your cholesterol and improving the function of your immune system.