Can Green Tea Fight Cancer and Cardiovascular Disease?
   

Can Green Tea Fight Cancer and Cardiovascular Disease?

Although many tea-drinking Americans have grown up on black tea, green tea is gaining popularity due to its reputation for promoting health. The major difference between black tea and green tea comes from the way they are produced. In black tea, the leaves are dried slowly, and during this time the antioxidants in the leaves disintegrate. In green tea, the leaves are slightly steamed and then quickly dried, protecting the antioxidants from disintegration. This simple difference in procedure makes all the difference in health. Antioxidants can be powerful tools for health, and many people know that vitamins C and E are good sources of antioxidants. It may not be as well known that the antioxidants in green tea are of even greater benefit than those in vitamins C and E. Beyond promoting overall health, the green tea antioxidants have also shown promise for disease prevention and control.

Recently, two researchers published separate reviews of studies looking at the relationship between green tea consumption and cancer rates. They determined that the more green tea a person consumes, the less likely he or she is to get colon, stomach, bladder, breast, pancreatic, esophageal, prostate, or skin cancer. However, many of the studies involved single cases and some relied on information from interviews, which can be subjective. More clinical trials are needed to establish this relationship.

Other studies seem to indicate that the antioxidants in green tea can lower cholesterol levels. One study showed that 10 cups a day of green tea was able to lower cholesterol levels; however, another study of 6 cups a day did not show these results. Again, more clinical trials are needed.

Most studies on green tea conclude that you need to drink 6 to 10 cups a day to see health benefits. One cup of green tea contains significantly less caffeine than coffee. However, when you multiply that amount by 6 to 10 times it adds up to a lot of caffeine. Since too much caffeine may cause side effects (such as insomnia, restlessness, headaches, nervousness, and rapid heartbeat), decaffeinated green tea is recommended. Green tea extracts are also available. A recommended dose for general health is 300 to 400 mg/day. (Look for a product that states that it has been standardized to contain 80 percent total polyphenols and 55 percent epigallocatechin.)

In other places in the world, green tea has been consumed to promote health and longevity for approximately 5,000 years. Recently, it has gained popularity in America. The research to date supports consuming green tea for general health benefits. However, more studies are needed to confirm its specific role in disease prevention.


References

Brown MD. Green tea (Camellia sinensis) extract and its possible role in the prevention of cancer. Altern Med Rev. 1999;4(5):360-370.

Bushman JL. Green tea and cancer in humans: a review of the literature. Nutr Cancer. 1998;31(3):151-159.

Imai K, Nakachi K. Cross sectional study of effects of drinking green tea on cardiovascular and liver diseases. BMJ. 1995;310(6981):693-696.

Integrative Medicine Access: Professional Reference to Conditions, Herbs & Supplements. Newton, Mass: Integrative Medicine Communications; 2000.

Komori A, Yatsunami J, Okabe S, et al. Anticarcinogenic activity of green tea polyphenols. Jpn J Clin Oncol. 1993;23(3):186-190.

Weisburger JH. Tea and health: the underlying mechanisms. Proc Soc Exp Biol Med. 1999;220(4):271-275.


Review Date: March 2000
Reviewed By: Integrative Medicine editorial

Copyright © 2004 A.D.A.M., Inc

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