Green Tea

Green tea has been used for medicinal purposes in India and China for nearly 5,000 years. Green tea extract is derived from leaves of camellia sinensis, the same plant of origin of black and oolong teas. There are many health benefits associated with Green tea extract, which include potential cancer-fighting properties and strong antioxidant effects that protect the body from toxic free radicals.

Green Tea Extract is an excellent source of potent, bioflavonoid rich compounds that are high in polyphenols, which are a special class of bioflavonoids. Catechins, and in particular Epigallocatechin Gallate (EGCG), is the most important polyphenol and has the strongest antioxidant action. Research has shown that EGCG is more powerful than vitamin E in neutralizing free radicals.

 

Benefits of Green Tea

Recent studies are beginning to establish the potential health benefits of green tea, especially in weight loss, heart health and cancer prevention. High amounts of green tea are consumed daily in China and Japan, and their cancer rates are statistically lower. Increasing research from reputable sources demonstrate the active ingredients in green tea extract may lower rates of various kinds of cancer.

A recent study in the Journal of Periodontology, has demonstrated another benefit of green tea consumption [1]. Researchers discovered that routine intake of green tea may also promote healthy teeth and gums. The study evaluated the periodontal health of 940 men, and discovered men who regularly drank green tea had better periodontal health than those who didn’t. This ability is most likely the result of the presence of the antioxidant catechin.

If Green tea can reduce the body’s inflammatory response to periodontal bacteria, it may help promote periodontal health and prevent other inflammatory associated diseases. For example, periodontal disease is a chronic inflammatory disease affecting the oral cavity but has also been shown to be an independent risk factor of other disease like diabetes, cardiovascular disease, and stroke.

Green tea has also been demonstrated to improve the function of endothelial cells lining the circulatory system and thus reduces the progression of atherosclerosis [2]. “These findings have important clinical implications,” says investigator Dr. Charalambos Vlachopoulos. “Tea consumption has been associated with reduced cardiovascular morbidity and mortality in several studies. Green tea is consumed less in the Western world than black tea, but it could be more beneficial because of the way it seems to improve endothelial function. In this same context, recent studies have also shown potent anticarcinogenic effects of green tea, attributed to its antioxidant properties.”

Green Tea and Cardiovascular diseases

A recent study from Japan was published in the Journal of the American Medical Association showing a significant reduction in deaths from cardiovascular disease among drinkers of green tea [3]. Investigators enrolled over 40,000 people and followed them prospectively for over eleven years. Subjects who drank more than five cups of green tea per day had a 16% lower risk of overall mortality, and of mortality related to cardiovascular disease, than for who drank less than one cup of green tea daily. These protective effects were stronger in women than in men. In addition, green tea consumption was particularly associated with a reduction in stroke mortality [3]. Benefits from green tea were seen in those who drank at least one cup per day. Several postulated mechanisms for these beneficial effects mediated by green tea include its antioxidant properties, and its effects on hypertension and LDL cholesterol.

Study examines the effect of Green Tea on Serum Lipid Profiles

A smaller study published in Nutrition Research (26(11):604-607) examined the effects of green tea supplementation on serum lipid profiles. Significant blood lipid changes occurred, including reduction of low-density lipoprotein cholesterol in 90% of subjects and an increase of high-density lipoprotein cholesterol in 69% of subjects. Since that time, studies have demonstrated catechins contained in green tea, especially epigallocatechin-3-gallate, inhibits the adherence of monocytes to vascular endothelial cells (an important early event in atherogenesis) [4]. Other studies in humans demonstrated green tea extract supplementation was effective in decreasing blood pressure, LDL cholesterol, oxidative stress, and chronic inflammation, which are independent cardiovascular risk factors [5].

Green Tea and Alzheimer’s disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder pathologically characterized by deposition of beta-amyloid peptides as plaques in the brain. Interestingly, oral administration of epigallocatechin-3-gallate (a catechin and the main polyphenolic constituent of green tea) reduce beta amyloid plaque burden in an Alzheimer’s mouse model [6]. Specifically, plaque burdens were decreased in the cingulate cortex, hippocampus, and entorhinal cortex by 53%, 53%, and 58%, respectively [6]. The authors conclude that their data raise the possibility that EGCG dietary supplementation may provide effective prophylaxis for Alzheimer’s disease. Another study demonstrated Epigallocatechin-3-gallate (EGCG) may be neuroprotective by inhibiting mitochondrial oxidative stress in neurons [7]. Human studies have demonstrated a higher consumption of green tea is associated with a lower prevalence of cognitive impairment [8].

 

  1. Kushiyama et al. Relationship Between Intake of Green Tea and Periodontal Disease. Journal of Periodontology, 2009; 80 (3): 372
  2. Alexopoulos et al. The acute effect of green tea consumption on endothelial function in healthy individuals. European Journal of Cardiovascular Prevention & Rehabilitation, 2008; 15 (3): 300
  3. Kuriyama S, Shimazu T, Ohmori K, et al. Green tea consumption and mortality due to cardiovascular disease, cancer and all causes in Japan. The Ohsaki study. JAMA2006;296:1255-65.
  4. Naito Y, Yoshikawa T. Green Tea and Heart Health. J Cardiovasc Pharmacol. 2009 Aug 7.
  5. Nantz MP, Rowe CA, Bukowski JF, Percival SS. Standardized capsule of Camellia sinensis lowers cardiovascular risk factors in a randomized, double-blind, placebo-controlled study.Nutrition. 2009 Feb; 25(2):147-54. 9.
  6. Rezai-Zadeh K, Arendash GW, Hou H, Fernandez F, Jensen M, Runfeldt M, Shytle RD, Tan J. Green tea epigallocatechin-3-gallate (EGCG) reduces beta-amyloid mediated cognitive impairment and modulates tau pathology in Alzheimer transgenic mice. Brain Res. 2008 Jun 12;1214:177-87.
  7. Schroeder EK, Kelsey NA, Doyle J, Breed E, Bouchard RJ, Loucks A, Harbison A, Linseman DA. Green tea epigallocatechin 3-gallate accumulates in mitochondria and displays a selective anti-apoptotic effect against inducers of mitochondrial oxidative stress in neurons. Antioxid Redox Signal. 2008 Aug 28.
  8. Kuriyama S, Hozawa A, Ohmori K, Shimazu T, Matsui T, Ebihara S, Awata S, Nagatomi R, Arai H, Tsuji I. Green tea consumption and cognitive function: a cross-sectional study from the Tsurugaya Project 1. Am J Clin Nutr. 2006 Feb;83(2):355-61.