Green tea is well known as a very healthy alternative to black tea and coffee. It is also a very tasty drink and very popular all over the world. But, what are its real nutritional qualities and what health benefits can you expect from drinking green tea?
What is Green Tea?
Green tea is made from the leaf of the tea bush, which is processed with as little oxidation (also known as fermenting) as possible by steaming the leaves after picking. Black tea is made from the same plant, but is oxidized after picking. Green tea comes in different varieties, usually distinguished by different methods of processing, different countries of origin and sometimes by added ingredients, such as jasmine flowers or lemon. Green tea is steeped (also known as brewing) at water temperatures below boiling (usually 150-185F, or 65-85C) for 2-3 minutes or less.
The Health Benefits of Green Tea
Green tea is an excellent source of polyphenols, as well as other types of antioxidants. Green tea also contains some vitamins and minerals such as vitamin C, chromium and selenium. Some studies have shown that drinking green tea can help to prevent heart disease, however exactly how it does this is still an area of debate. Another study suggested that drinking green tea may increase the rate of fat burning during exercise, as well as improve insulin sensitivity. This is a valuable trait for diabetics, individuals with insulin resistance and those wishing to decrease their weight.
Green tea may also reduce the likelihood of developing Alzheimer's disease by helping to protect brain function in aging individuals. Drinking green tea has been linked to lower incidence of breast cancer, possible prevention of eye disease, lower levels of DNA damage from smoking, prevention of stomach ulcers and lower incidences of other cancers like stomach and colon cancer. Green tea is also an anti-bacterial and may even help to prevent cavities in teeth, as well as gingivitis.
Cautions About Green Tea
Green tea is a relatively safe beverage to consume with very few calories. It does contain caffeine which is a mildly addictive stimulant, so drinking too much green tea per day (some experts recommend 3 or more cups per day for the full benefits) can lead to insomnia, nervousness and other excess caffeine symptoms, particularly in people who are not used to it. However, green tea contains much less caffeine than coffee and a little less than black tea.
Drinking very hot drinks has been linked to a higher incidence of mouth and throat cancer, as the lining of the mouth is damaged by repeated mild scalding. This can be avoided by waiting until the tea is cooler before drinking it. Green tea can also prevent the absorption of iron, and interfere with certain prescription drugs. Drinking excessive amounts of green tea is not recommended during the first trimester of pregnancy.