The Chinese have known about the medicinal benefits of green tea since ancient times, using it to treat everything from headaches to depression; it has been used as a medicine in China for at least 4,000 years. Chinese legend says that green tea was first drunk when the Chinese emperor was sitting under a tea bush and a few leaves fell into his cup of hot water; he sipped the brew and felt good. Green tea has always been, and remains today, the most popular type of tea from China where most historians and botanists believe the tea plant originated.

The more processing tea leaves undergo, the darker they will turn. Green tea (which is harvested from a tree called Camellia sinensis) is the least processed tea. The leaves are simply steamed quickly; the resulting greenish-yellow tea has a flavor close to the taste of the fresh leaf. Black and red teas are partially dried, crushed and fermented. Because Green tea is the least processed it provides the most antioxidant polyphenols. All teas contain polyphenols. These are strong antioxidants that can protect against cell damage and, in one Japanese study, the tea has been shown to help to prevent heart disease. Green tea also contains fluoride, which protects your teeth from decay.

Today, scientific research in both Asia and the West is providing evidence for the health benefits long associated with drinking green tea. For example, in 1994 the Journal of the National Cancer Institute published the results of a study indicating that drinking green tea reduced the risk of esophageal cancer in Chinese men and women by nearly 60 percent. University of Purdue researchers recently concluded that a compound in green tea inhibits the growth of cancer cells. It has also shown to be helpful in protecting DNA from damage. Numerous studies have demonstrated the anti-cancer properties of polyphenols. Some studies indeed suggested that tea's polyphenols may reduce risk of gastric, esophageal and skin cancers if one consumes four to six cups daily. There is also research indicating that drinking green tea lowers total cholesterol levels and contains lots of vitamin K. New evidence is emerging that green tea may even help dieters. Green tea may even help prevent tooth decay! It can also kill the bacteria that cause dental plaque.

To sum up, here are just a few medical conditions in which drinking green tea may be helpful: cancer, rheumatoid arthritis, high cholesterol levels, cardiovascular disease, infection, impaired immune function and weight loss.

To date, the only negative side effect that has been reported from drinking green tea is insomnia due to the fact that it contains caffeine. However, green tea contains less caffeine than coffee: enjoying a daily cup of green tea may help your overall health and well-being and it makes a healthy change from coffee. Try a pot of green tea with a Chinese supper. It really brings out the flavors.

While it is good to try green tea to as a change from tea and coffee water should always be your main drink of the day.

Could you explain two things for me? What is the difference between cod liver oil and fish oil?

— Mohammed

Both cod liver oil and fish oil contain omega-3 fatty acids, including EPA (eicosapentaenoic acid) and DHA (docosapentaenoic acid). The difference is that cod liver oil also contains vitamins A and D; fish oil does not contain these vitamins. Cod liver oil is made from the liver of the cod fish; and fish oil can be made from the bodies of several different kinds of cold water fish.

— Alva