Green Tea: As Good as They Say it is! Lucy Honold Beloit College, Beloit, WI

1. Green Tea in Comparison to Other Beverages: As this graph shows, green tea has much higher levels of antioxidants than many other beverages and foods. Even orange juice, which is often advertized in terms of amounts of vitamin C, another substance that works against free radicals, has far less antioxidant activity than green tea. There are, of course, other beverages, such as red wine, with high levels of antioxidants, but this graph is helpful in comparing green tea to other items that are often advertised as being high in antioxidants. Abstract Research has shown that green tea has the ability to prevent serious diseases such as cancer and diabetes, as well as things like the symptoms of the common cold. Many sources say that the recommended daily value of green tea should be set at 3-4 cups, but this value is as yet being debated. This poster examines both the ideal dosage of green tea that will allow for the greatest amount of health benefits, as well as which of the benefits attributed to green tea are backed up by science, and which are simply promoted by companies that make green tea. Proven benefits include reduced risk of cognitive decline, heart disease, obesity and death. Introduction This poster presents results from in depth review of the claims made about the health benefits of green tea in an attempt to discern which have truth behind them. Most of these benefits are attributed to EGCG - Epigallocatechin gallate (Figure 1), a chemical found in green tea that is a powerful antioxidant. Some of the claims made about green tea are that it can help prevent everything from serious diseases such as cancer and diabetes to the symptoms of the common cold. Green tea is often hailed as a cure-all and most sources say that 2-3 cups a day can significantly improve one’s overall health. Given the large number of benefits attributed to green tea and the fact that the mechanism of benefits is still uncertain, it is important to separate well-supported benefits from speculation that is most likely propagated by the companies that sell green tea. I am hypothesizing that green tea does in fact have antioxidative properties, but that any measureable positive effects on one’s health are marginal, and probably better attributed to the overall lifestyle of people who regularly drink green tea. Method I examined many studies about the recommended daily value of green tea, as well as about the truth behind attributed health benefits. I used studies comparing the effects of different amounts of tea, as well as scientific papers regarding the specific chemicals found in green tea that are said to be responsible for the health benefits. The vast majority of my sources are peer reviewed, and come from places like The American Journal of Clinical Nutrition, The International Journal of Cancer, and the University of Maryland Medical Center. Summary of Research Figure 2: ½ cup of green tea per day: 47% reduced risk of breast cancer (ref) Green Tea: As Good as They Say it is!Lucy HonoldBeloit College, Beloit, WI 1 cup of green tea per day: Lower plasma glucose levels and 750 kJ of extra energy expenditure(ref) Discussion: The research that I have done has left me with the conclusion that benefits of green tea vary greatly when one drinks green tea in different amounts. While one cup a day may be enough to keep the symptoms of the cold at bay, or aid in weight loss, in order to reap the benefits of preventing cancer and diabetes, one should drink about four cups a day. There was also no evidence found that led me to believe that there is practically such a thing as too much green tea. While drinking say, eight cups of green tea a day would not insure any more benefits, it would not cause harm. 3 cups of green tea per day: 54% reduced cognitive decline after 70(ref) 3 ½ cups of green tea per day: Reduction in body fat(ref) • References • “Antioxidant levels of common teas vary widely.” Reuters. 27 February 2002. 9 February 2006. • <<http://www.heartcenteronline.com/myheartdr/News_about_the_heart/Antioxidant_levels_of_ • common_teas_vary_widely.html>> • 2. Berube-Parent, S., et al. “Effects of encapsulated green tea and Guarana extracts containing a mixture of • epigallocatechin-3-gallate and caffeine on 24 h energy expenditure and fat oxidation in men.” The • British Journal of Nutrition 94 (2005): 432-6. • 3. Nagao, T., et al. “Ingestion of a tea rich in catechins leads to a reduction in body fat and malondialdehyde- • modified LDL in men.” American Journal of Clinical Nutrition 81 (2005): 122-9. • 4. Ordman, Roc. “NOTES ABOUT TEA-GREEN TEA IS NEARLY MAGICAL!” Beloit College. 1 June 2005. 9 • February 2006. << http://www.beloit.edu/~nutritio/tea.htm >> • 5. Shinichi, Kuriyama, et al. “Green tea consumption and cognitive function: a cross-sectional study from the • Tsurugaya Project.” American Journal of Clinical Nutrition 83 (2006): 355-61. • 6. Shirai, N., and Suzuki, H. “Effects of Western, Vegetarian, and Japanese dietary fat model diets with or • without green tea extract on the plasma lipids and glucose, and liver lipids in mice. A long-term • feeding experiment.” Annals of nutrition & metabolism 48 (2004): 95-102. • 7. “Survey: In U.S., Green Tea Ranks Last.” American Institute for Cancer Research. 14 July, 2005. • << http://www.aicr.org/site/News2?abbr=pr_&page=NewsArticle&id=8207>> • 8. Wu, AH, et al. “Green tea and risk of breast cancer in Asian Americans.” International Journal of Cancer • 106 (2003): 574-9. • 9. Sueoka, N., Suganuma, M., Sueoka, E., Okabe, S., Matsuyama, S., Imai, K., Nakachi, K. and Fujiki, H. • (2001), A New Function of Green Tea: Prevention of Lifestyle-related Diseases. Annals of the New York Academy of Sciences, 928: 274–280. doi: 10.1111/j.1749-6632.2001.tb05656.x • 10. Green tea. (2010). Retrieved from http://www.umm.edu/altmed/articles/green-tea-000255.htm • 11. J Agric Food Chem. 2010 Feb 10;58(3):1523-34. Green tea catechins and their oxidative protection in the rat eye.Chu KO, Chan KP, Wang CC, Chu CY, Li WY, Choy KW, Rogers MS, Pang CP. Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong. • Images: • http://www.redrosetea.ca/health_and_wellness/goodness_of_antioxidants.aspx • http://www.herbs-tech.com/product/egcg.asp Figure 1: Structure of EGCG 4 cups of green tea per day: 45% lower risk of second heart attack and 10% increase in longevity(ref) EGCG The health benefits of green tea are attributed to the fact that the tea contains many polyphenols, which are powerful antioxidants, in the form of catechins. The most potent of these, the one that is most often cited as the reason that green tea is so good for you, is EGCG. It is one of the most prevalent catechins, comprising up to 50% of the catechin activity in green tea, and has been found to be 25 times more effective than vitamin E, and 100 times more effective than vitamin C, at scavenging free radicals (ref).