Over the last few decades green tea has been subjected to numerous scientific and medical studies to determine the extent of its long-purported health benefits, with some evidence suggesting that regular green tea drinkers may have a lower risk of developing heart disease and certain types of cancer. Although green tea does not raise the metabolic rate enough to produce immediate weight loss, a green tea extract containing polyphenols and caffeine has been shown to induce thermogenesis and stimulate fat oxidation, boosting the metabolic rate 4% without increasing the heart rate.
The mean content of flavonoids in a cup of green tea is higher than that in the same volume of other food and drink items that are traditionally considered to be of health contributing nature, including fresh fruits, vegetable juices or wine. Flavonoids are a group of phytochemicals present in most plant products that are responsible for health benefits such as anti-oxidative and anticarcinogenic functions. However, the content of flavonoids may vary dramatically amongst different tea products.