Healthy Benefits of Green Tea

Having a cup, or two or three, of soothing hot green tea is one of the best things you can do for yourself. There are so many benefits to this tea it's hard to discuss them all without writing a full book, but I'll try to cover the main ones for you.

First of all, what is green tea and why is it different, better, than other teas? It does come from the same plant, the Camelia sinensis, as black, oolong and white tea but it's processed differently than the rest. Black tea is fully fermented and oolong teas are partially fermented. Green and white teas aren't put through that process at all, which leaves more of the beneficial compounds, and less of the more harmful ones like caffeine and tannins, in the final product.

The most helpful constituents in green tea are a class of polyphenols called catechins. There are six primary ones including the one you're probably most familiar with - EGCG. These catechins have strong antioxidant activities and are said to be more powerful than even vitamin C (University of Maryland Medical Center); but only about 15% of these are left in black and oolong tea after fermentation (American Botanical Council). What they are exactly and what their specific activities are is beyond the scope of this paper, but they all contribute to the benefits we experience from this delicious tea.

One of the main contributions that green tea makes is to the cardiovascular system. It reduces the risk of atherosclerosis, heart attack and other cardiovascular diseases by allowing higher antioxidant activity and decreasing fat and cholesterol levels in the blood (ABC). Results released in 2006 from a study done in Japan (the Ohsaki study) found that women who drink 5 cups or more of green tea daily have a 31% less chance of dying from cardiovascular disease than those who drink 1 cup or less daily (Shinichi Kuriyama).

Green tea is definitely heart healthy; several studies noted in an article by Drs. Basu and Lucas show a correlation between drinking 2 cups or more a day and a reduced risk of heart attack and hypertension, and coronary artery disease. They also note that drinking a cup or two or taking green tea extracts with or before meals could help lower triglyceride levels even more than it would taking it any other time. Making this beverage a regular habit also helps lower your cholesterol levels and your blood pressure.

Green tea also protects against several types of cancer including breast and ovarian cancer, colon cancer, squamous cell lung cancer, pancreatic cancer and esophageal cancer. According to an article on green tea by researchers at the University of Maryland Medical Center the polyphenols in green tea (and black tea) inhibit the growth of cancer cells in population-based studies, animals and test tubes but that more research needs to be done to prove that's true in people. However, in a study done on green tea and the prevention of breast cancer, "the risk of breast cancer declined with increasing quantity, duration and frequency of green tea consumed." (Min Zhang, C. D’Arcy J. Holman, Jiang-ping Huang, and Xing Xie). A study done by Scott A. Laurie, Vincent A. Miller, Stefan C. Grant, Mark G. Kris, and Kenneth K. Ng also shows a promising correlation between green tea extract and the reduced risk of lung cancer.

Part of a study on the mechanisms and effects of green tea on cardiovascular health revealed that consumption of 6 g (about 1 tbsp) of green tea infused in a little over 10 oz of hot water caused a significant decrease in free radical damage among heavy smokers (Arpita Basu, PhD, and Edralin A. Lucas, PhD); this has to be a plus as far as lung cancer prevention is concerned.

Green tea catechins help with another major concern for a lot of people, and that is weight loss and abdominal fat. The findings of a study published in 2008 show that a dose of 625 mg per day of green tea extract in conjunction with a minimum of 3 hours per week of moderate exercise, was associated with greater weight loss, significant reductions in total and subcutaneous abdominal fat, and serum triglycerides ( Kevin C. Maki, Matthew S. Reeves, Mildred Farmer, Koichi Yasunaga, Noboru Matsuo, Yoshihisa Katsuragi, Masanori Komikado, Ichiro Tokimitsu, Donna Wilder, Franz Jones, Jeffrey B. Blumberg, and Yolanda Cartwright).

Several studies say that more research is needed to show that green tea can reduce the risk of Type II diabetes but in a study done by H. Iso, C. Date, K. Wakai, M. Fukui, and A. Tamakoshi results show that drinking 6 cups or more of green tea per day can reduce that risk by 33%.

Other benefits you can experience from drinking green tea are an overall feeling of well-being, extra energy without feeling like you're hyper, improved bone density, help in treating/relieving symptoms from Crohn's disease, improved cognitive performance, relief in cases of osteoporosis, arthritis, and other joint pain; it also assists with the elimination of alcohol and toxins from the body, improves your digestive health and gives relief from anxiety.

If you'd like to see how green tea will work for you, you can buy the tea bags in any grocery store or you can make your own infusion with dried green tea leaves. To make an infusion just add 1 teaspoon in a cup of boiled water and let steep for about 10 minutes (you can heat it up again after that if you don't like your tea room temperature). A typical cup of green tea contains between 300-400mg polyphenols, of which 10-30mg of that is EGCG. You can drink up to 10 cups a day; long term use at this amount is okay with no adverse side effects (Dennis J. McKenna, Kerry Hughes, and Kenneth Jones). If you prefer iced tea, rather than hot tea, just make sure you don't use ice cubes; chill it without the ice. The beneficial catechins tend to bind to the ice diminishing their effectiveness.

You can also buy green tea capsules. If this is your choice, make sure you look for a product that's standardized to contain between 80-90% polyphenols and/or 35-55% EGCG and follow the dosage on the bottle. Anywhere from 500mg to 1500mg of the green tea capsules a day is a fairly good guideline, with the higher end of that dosage used to help prevent cancer.

If you're using it for the thermogenic effects to help you lose weight and reduce your waistline, 2000 mg a day divided into 3 doses should give you about a six pound and one inch loss after two weeks. There were no side effects, including sleep loss, reported while following this regimen (McKenna et.al.) Green tea is safe to use even for long periods of time, and no toxic effects have been reported from normal use at the recommended doses. It's also safe to use during pregnancy and breastfeeding. However, as a measure of safety you shouldn't give green tea to infants, and you should avoid using it if you have end-stage renal disease. Some people have experienced diarrhea with doses over 600mg a day, but that doesn't seem to be a common problem.

References:
American Botanical Council. Tea, Black/Green Clinical Overview. Excerpt from The ABC Clinical Guide to Herbs. Retrieved May 19, 2009 from http://abc.herbalgram.org/site/PageServer?pagename=The_Guide#Samples

Arpita Basu, Edralin A Lucas. (2007). Mechanisms and Effects of Green Tea on Cardiovascular Health. Nutrition Reviews,1 65(8), 361-75. Retrieved June 9, 2009, from Research Library Core database. (Document ID: 1342247891).

Dennis J. McKenna, Kerry Hughes, and Kenneth Jones (2000). Green Tea Monograph found on ProQuest

Iso H, Date C, Wakai K, Fukui M, Tamakoshi A; the JACC Study Group. The relationship between green tea and total caffeine intake and risk for self-reported type 2 diabetes among Japanese adults. Ann Intern Med. 2006; 144:554-562.Health-Cares . net (retrieved 6/9/2009).

Kevin C Maki, Matthew S Reeves, Mildred Farmer, Koichi Yasunaga, Noboru Matsuo, Yoshihisa Katsuragi, Masanori Komikado, Ichiro Tokimitsu, Donna Wilder, Franz Jones, Jeffrey B Brumberg, Yolanda Cartwright. (2009). Green Tea Catechin Consumption Enhances Exercise-Induced Abdominal Fat Loss in Overweight and Obese Adults1,2. The Journal of Nutrition, 139(2), 264-70. Retrieved June 9, 2009, from Research Library Core database. (Document ID: 1663895911) Min Zhang, C. D'Arcy J. Holman, Jiang-ping Huang, Xing Xie. (2007). Green tea and the prevention of breast cancer: a case-control study in Southeast China. Carcinogenesis, 28(5), 1074-8. Retrieved June 9, 2009, from ProQuest Health and Medical Complete database. (Document ID: 1265152701).

Natural Standard Monograph, (2009). Green Tea . Retrieved May 19, 2009 from www.naturalstandard.com/monographs/herbssupplements/green_tea

Scott A. Laurie, Vincent A. Miller, Stefan C. Grant, Mark G. Kris, Kenneth K. Ng. (2005). Phase I study of green tea extract in patients with advanced lung cancer. Cancer Chemotherapy and Pharmacology, 55(1), 33-8. Retrieved June 9, 2009, from ProQuest Health and Medical Complete database. (Document ID: 749788531).

Shinichi Kuriyama. (2008). The Relation between Green Tea Consumption and Cardiovascular Disease as Evidenced by Epidemiological Studies1,2. The Journal of Nutrition, 138(8), 1548S-1553S. Retrieved June 9, 2009, from Research Library Core database. (Document ID: 1552221861).

University of Maryland Medical Center. Green tea. www.umm.edu/altmed/articles/green-tea-000255.htm Retrieved June 9, 2009