Cheng Tsung O
Department of Medicine, The George Washington University Medical Center, 2150 Pennsylvania Avenue, N.W., Washington, DC 20037, USA.
Int J Cardiol. 2006 Apr 14;108(3):301-8. doi: 10.1016/j.ijcard.2005.05.038. Epub 2005 Jun 22.
Tea is one of the most widely consumed beverages in the world, next only to water. It can be categorized into three types, depending on the level of fermentation, i.e., green (unfermented), oolong (partially fermented) and black (fermented) tea. In general, green tea has been found to be superior to black tea in terms of antioxidant activity owing to the higher content of (-)-epigallocatechin gallate. The processes used in the manufacture of black tea are known to decrease levels of the monometric catechins to a much greater extent than the less severe conditions applied to other teas. The cardioprotective effect of flavonoids from green tea can be attributed to not only antioxidant, antithrombogenic and anti-inflammatory properties but also improvement of coronary flow velocity reserve. In this article, I will discuss the effects of green tea on atherosclerosis, coronary heart disease, hypertension, diabetes, metabolic syndrome and obesity, and, finally, its comparison with black tea.
茶是世界上消费最为广泛的饮品之一，仅次于水。根据发酵程度，茶可分为三类，即绿茶（未发酵）、乌龙茶（半发酵）和红茶（全发酵）。一般来说，由于（-）-表没食子儿茶素没食子酸酯含量较高，绿茶在抗氧化活性方面优于红茶。众所周知，红茶的制作工艺比其他茶类所采用的较温和工艺能更大程度地降低单体儿茶素的含量。绿茶中黄酮类化合物对心脏的保护作用不仅可归因于其抗氧化、抗血栓形成和抗炎特性，还可归因于其对冠状动脉血流速度储备的改善作用。在本文中，我将探讨绿茶对动脉粥样硬化、冠心病、高血压、糖尿病、代谢综合征和肥胖症的影响，最后还将探讨绿茶与红茶的比较。
