Can drinking several cups of green tea a day keep the doctor away? This certainly seems so, given the popularity of this practice in East Asian culture and the increased interest in green tea in the Western world. Green tea is a popular beverage that is consumed worldwide and therefore the health benefits of green tea has become an important topic to study. Most green tea research papers focus on different health benefits of green tea? Below we have summarized the latest finding related to green tea benefits.
Drinking green tea is beneficial to the heart
The Ohsaki National Health Insurance Cohort Study is an earlier study on the health benefits of green tea in 2006 conducted by major Japanese health scientists. This massive study involving more than 40.000 participants aged 40-79 years without history of stroke, coronary heart disease, or cancer at baseline and took 11 years to complete. This study provides strong support green tea consumption on average results in lower chance of mortality, especially mortality caused by heart disease. While studying the relationship between mortality due to cancer and green tea drinking was also in scope of this research, a significant relation was not found. Even though a relationship between green tea and mortality was established, this study however does not explain the reason/process behind it.
A more recent study conducted in Japan by Kishimoto (2013) focus more on the why drinking green tea is good for health. This study provide evidence that Japanese people intake polyphenol mainly from drinking green tea beverages and this polyphenol act as an antioxidant against low protein lipoprotein, which is known to cause atherosclerosis and leads to heart disease (or also called cardiovascular diseases). The purpose of study is to review recent findings related to daily intake of polyphenol and their possible relationship to cardiovascular diseases. The result of study summarized that dietary polyphenol could protect against heart diseases through their ability to improve metabolic disorder and avoid blood vessels inflammation. Metabolic disorder and blood vessels inflammation are major causes of heart disease. Thus there are positive effects of drinking green tea for the heart.
Reference: Shinichi Kuriyama, MD, PhD; Taichi Shimazu, MD; Kaori Ohmori, MD, PhD; Nobutaka Kikuchi, MD; Naoki Nakaya, PhD; Yoshikazu Nishino, MD, PhD; Yoshitaka Tsubono, MD, PhD; Ichiro Tsuji, MD, PhD (2006). Green Tea Consumption and Mortality Due to Cardiovascular Disease, Cancer, and All Causes in Japan. JAMA. 2006;296(10):1255-1265. doi:10.1001/jama.296.10.1255.
Reference: Kishimoto Y, T. M. (2013). Pleiotropic preventive effects of dietary polyphenols in cardiovascular diseases. Eur J Clin Nutr, 67(5):532-5.
Cholesterol lowering effect of green tea
In a cooperation between Chinese and Western scientist in 2003 scientific proof was found that drinking green can lower cholesterol level of people with high levels of cholesterol in blood. In total, 240 men and women of 18 years or older on a low-fat diet with hypercholesterolemia were randomly assigned to receive a daily capsule containing theaflavin-enriched green tea extract (375 mg) or placebo for 12 weeks. Participants who were taking the green tea capsule had lowered their cholesteral levels significantly compared to the control group that were given the placebo capsule that contained no green tea extract. Thus, one major health benefit of green tea is that it can people lower cholesterol levels and thereby prevent heart diseases.
David J. Maron, MD; Guo Ping Lu, MD; Nai Sheng Cai, MD; Zong Gui Wu, MD; Yue Hua Li, MD; Hui Chen, MD; Jian Qiu Zhu, MD; Xue Juan Jin, MS; Bert C. Wouters, MA; Jian Zhao, PhD (2003). Cholesterol-Lowering Effect of a Theaflavin-Enriched Green Tea Extract. Arch Intern Med. 2003;163(12):1448-1453. doi:10.1001/archinte.163.12.1448.
Green tea protects the skin
In 2000 a review study has been performed on several major researches on how green tea is related to skin health. Analysis of published studies demonstrates that green tea polyphenols have anti-inflammatory and anticarcinogenic properties. These effects appear to correlate with antioxidant properties of green tea polyphenols. The studies under review included animal as well as human studies. Results also suggest that supplementation of skin care products with green tea may have a profound impact on various skin disorders in the years to come. Skin health benefits of green tea seems to be huge.
Säntosh K. Katiyar, PhD; Nihal Ahmad, PhD; Hasan Mukhtar, PhD (2000). Green tea and skin. Arch Dermatol. 2000;136(8):989-994. doi:10.1001/archderm.136.8.989.
Antibacterial and antiviral effects of green tea ECGC
A recent study summarizes the antibacterial, antiviral and antifungal effect of green tea ECGC (epigallocatechin-3-gallate).The study performed by Steinman in 2013 shows that green tea have many physiological and pharmacological health benefits and during this study the anti infective properties of ECGC (epigallocatechin-3-gallate) was studied. The study shows that this green tea constituent is effective against large number of human pathogen viruses including influenza A virus, Hepatitis virus and HIV virus. In addition to this the antibacterial effect of green tea ECGC alone or in combination with different antibiotics was analyzed against number of bacterias.The study also shows the antifungal effect of drinking green tea against Yeast and finally the researcher concluded that green tea drinking is linked with many antiviral, bacterial and antifungal health effects.
Reference: Steinmann J, B. J. (2013). Anti-infective properties of epigallocatechin-3-gallate (EGCG), a component of green tea. Br J Pharmacol, ;168(5):1059-73.
Smoking, lung cancer and green tea
The author of study conducted a systematic review of green tea for prevention and treatment of lung cancer. Green tea is a very popular beverage widely used by lung cancer patients because of its anti cancer properties. During study 6 electronic database were searched until November 2011 for human preclinical evidence related to effects of green tea consumption and lung cancer. The studies shows that their was no no tumor response at maximum tolerated dose range from 3 to 4.2g/m green tea extract per day. Researcheres however did find that four cup of daily intake of green tea decreased DNA damage of smokers. Finally the researchers concluded that although some evidence suggested their are chemopreventive health benefits of drinking green tea. However, there is still insufficient evidence to support green tea as a treatment or preventive agent for lung cancer.
Reference: Fritz H, S. D. (2013). Green tea and lung cancer: a systematic review. Integr Cancer Ther, ;12(1):7-24.
Effect of green tea extract on fat metabolism
Green tea is rich in polyphenol catechin and caffeine and there is interesting evidence about the potential role of green tea extract in fat metabolism and its influence on human health. A study conducted by Adrian B. Hodgson in 2013 observed positive effects of green tea extract on fat metabolism while resting and during exercise. The study, however, does not show the exact mechanism through which green tea extract plays role in improving fat metabolism.
Reference: Adrian B. Hodgson. (2013). The Effect of Green Tea Extract on Fat Oxidation at Rest and during Exercise: Evidence of Efficacy and Proposed Mechanisms1. Adv Nutr, 4: 129-140.
Antioxidant benefits of green tea against kidney diseases
Green tea contains polyphenols and it plays an important role in maintaining human health because of its anti oxidant activity. Anti oxidants protects the human body against diseases caused by oxidative toxics in the body. A study conducted by Takako Yokozawa in 2012 investigated the effect of green tea polyphenol on kidney disease. The result of study clearly indicated that green tea polyphenols have beneficial effect on pathological diseases related to oxidative stress of kidney. During this study the researcher investigated the effect of EGCG (epigallocatechin 3-O-gallate), one major tea polyphenol, on kidney health.
Reference: Takako Yokozawa, 1. J. (2012). Green Tea Polyphenols for the Protection against Renal Damage Caused by Oxidative Stress. Evidence-Based Complementary and Alternative Medicine, Volume 2012 (2012), Article ID 845917, 12 pages.
Drinking green tea and Parkinson disease
A study conducted by Feng-Jiao Li in 2012 evaluates an association between drinking green tea and Parkinson disease. The basic purpose of study is to summarize the risk of Parkinson disease with drinking green tea. The researcher searched all publications that are published till 2010 including 1418 cases and 4250 control related to effect of drinking green tea on Parkinson disease. The study of eight articles by researcher provides evidence about the protective effect of drinking green tea against Parkinson disease. The study suggested that tea drinking can lower the risk of Parkinson disease but still efforts are needed to understand the exact mechanism through which green tea lower risk of Parkinson disease.
Reference: Feng-Jiao Li, H.-F. J. (2012). A Meta-Analysis of Tea Drinking and Risk of Parkinson's Disease. The Scientific World Journal, Volume 2012 (2012), Article ID 923464, 6 pages.
Green tea, oral health and quit smoking
Green tea is the major source of polyphenol antioxidant. A study conducted by provide evidence that green tea protects against bacteria that induce dental problems. The study suggested that polyphenol have anti viral properties that help to protect against influenza virus and the polyphenols are also responsible for modification of orderent sulphur component. The study also suggested the beneficial effects of green tea in case of cigarette smoking and study suggested that the chemical like nicotine and arecoline in chronic smokers may be reduced in those people who use green tea.
Reference: Baruch Narotzkia, A. Z. (2012). Green tea: A promising natural product in oral health. Archives of Oral Biology, Volume 57, Issue 5, May 2012, Pages 429–435.
Anticancer activity and green tea
Green Tea polyphenol have been shown to inhibit tumor progression. A study by Pierpaola Davalli in 2012 support the existence of an association between green tea polyphenol consumption and a reduced cancer risk. The study was specifically focused on prostate cancer because prostate cancer grows slowly, and thus long time period is available to provide therapeutic treatment. The researcher conclude that polyphenol inhibited tumor onset and progression and now there is an increasing trend of employing the green tea as a part of a treatment in those patients who were diagnosed with less advanced prostate cancer. Thus green tea intake helps to delay progression of cancer disease and improve quality of life of patients.
Reference: Pierpaola Davalli, 1. F. (2012). Anticancer Activity of Green Tea Polyphenols in Prostate Gland. Oxidative Medicine and Cellular Longevity, Volume 2012 (2012), Article ID 984219, 18 pages.
Functional disability in eldery and green tea
A lot of studies indicated that green tea consumption is associated with lower risk of diseases that cause functional disability including stroke, cognitive impairment and osteoporosis. A study conducted by Yasutake Tomato in 2012 was investigated the association between green tea consumption and incident functional disability in elderly individual. For this study purpose 13,988 Japanese individuals aged greater than 65 was included in the study and information about daily green tea intake and other life style factors was collected through questionnaires.The result of the study clearly indicated that green tea consumption is significantly associated with a lower risk of functional disability.
Reference: Yasutake Tomata, M. K. (2012). Green tea consumption and the risk of incident functional disability in elderly Japanese: the Ohsaki Cohort 2006 Study1,2,3. Am J Clin Nutr, vol. 95 no. 3 732-739.
DNA protective effect of green tea
To see if drinking green tea daily would reduce DNA damage a study was on a group of healthy men and women, aged 35–50 years. The research participants were asked to drink either green tea (150 ml, twice daily) or water for 4 weeks. At the end of the study DNA damaged was assessed using a test called the comet assay, which measures changes in oxidation-induced DNA damage and resistance of DNA to oxidant challenge. After four weeks the green tea drinkers had actually lowered their initial level of DNA damage by 30%. The research paper concluded that these DNA protective effects (also called: genoprotective effect) of green tea lend support to its use as a functional food and provide scientific evidence for a more confident recommendation of regular intake of green tea for health promotion.
Reference: Han KC, W. W. (2011). Genoprotective effects of green tea (Camellia sinensis) in human subjects: results of a controlled supplementation trial. Br J Nutr, 105(2):171-9.
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