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| home : how we can help : prevention, screening, & diagnostics : answers to cancer : diet & nutrition
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Question: I have heard that tea is a healthy beverage. Is this true and what is the difference between green and black tea?
Answer: Yes, tea seems to have some health promoting qualities. Both black and green tea have been shown for sometime to have antioxidant properties, most likely due to their high flavonoid content. These substances are capable of deactivating potentially harmful free radicals which are formed by cellular oxidation. More recently tea has been studied in animal experiments and has been found to have several properties which could fight cancer at all four stages of development from initiation, promotion and progression to metastasis. More studies need to be done in humans to determine if this same anti-cancer activity seen in the lab and in animals will benefit humans. If it does prove to be effective, many questions need to be answered such as how much does one need for protection and how should it be prepared. Should boiling water be used, how long should it be steeped and does adding any other ingredients to the tea destroy or enhance its cancer-fighting properties?
In the meantime many people are willing to follow JapanŐs example, a country with generally lower cancer rates whose population consume an average of 3-4 cups of green tea each day. Other research indicates that perhaps only 1 cup of black or green tea may offer protection. In any case, tea can be one more component of a healthy diet that includes plenty of fruit, vegetables and whole grains.
Green tea and black tea come from the same plant Camellia sinensis, an evergreen. Green tea leaves are steamed just long enough to destroy the fermenting enzymes, rolled and dried without fermentation. Black tea leaves are rolled to release their juices and are fermented and dried. It appears that tea which is made from brewed tea has higher antioxidant activity than those prepared from powdered or instant tea. Herbal teas are made from the leaves, flowers, roots or stems of other plants and also have many phytochemicals which may be protective.
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