Boon Niels
Unilever R&D Vlaardingen, Vlaardingen, The Netherlands.
Int J Vitam Nutr Res. 2008 Dec;78(6):275-81. doi: 10.1024/0300-9831.78.6.275.
Obesity is a major health problem in the developed and developing world. Many "functional" foods and ingredients are advocated for their effects on body composition but few have consistent scientific support for their efficacy. However, an increasing amount of mechanistic and clinical evidence is building for green tea. The tea plant is naturally rich in a group of antioxidants known as catechins. Unlike black tea, green tea production involves little processing and fermentation and therefore, green tea brews are rich in catechins. Green tea has been suggested to have a number of potential health benefits in areas such as cardiovascular disease, cancer prevention, glucose homeostasis and dental health. Although there is some promising evidence in all of these areas, more data from human intervention trials are needed. A lot of attention has lately been focused on the beneficial effects of green tea on body composition and particularly visceral fat, which has been shown to have a strong link with different components of the metabolic syndrome such as cardiovascular disease and type 2 diabetes. Most, but not all, of the positive results come from a number Asian studies, in which overweight subjects (men and women) consumed green tea for approximately 12 weeks. Finally, green tea may also have measurable acute effects on energy metabolism and fat oxidation and in particular during physical activity, as evidenced by other studies specifically looking at these endpoints. Small cumulative effects on energy metabolism could also be responsible for the longer-tem effects of green tea on body composition, and these long-term effects may also be most apparent in the context of moderate physical activity. However, more research is needed to further clarify the exact mechanisms of action and to extrapolate these findings to non-Asian populations.
肥胖是发达国家和发展中国家面临的一个主要健康问题。许多“功能性”食品和成分因其对身体成分的影响而受到推崇，但很少有能持续获得科学依据支持其功效的。然而，越来越多关于绿茶的机制性和临床证据正在积累。茶树天然富含一类被称为儿茶素的抗氧化剂。与红茶不同，绿茶的生产几乎不涉及加工和发酵，因此，绿茶冲泡液富含儿茶素。绿茶已被认为在心血管疾病、癌症预防、葡萄糖稳态和口腔健康等领域有许多潜在的健康益处。尽管在所有这些领域都有一些有前景的证据，但仍需要更多来自人体干预试验的数据。最近，很多注意力都集中在绿茶对身体成分，特别是内脏脂肪的有益影响上，内脏脂肪已被证明与代谢综合征的不同组成部分，如心血管疾病和2型糖尿病有很强的联系。大多数（但不是全部）积极结果来自一些亚洲研究，在这些研究中，超重受试者（男性和女性）饮用绿茶约12周。最后，其他专门针对这些终点的研究表明，绿茶可能对能量代谢和脂肪氧化也有可测量的急性影响，特别是在体育活动期间。对能量代谢的微小累积影响也可能是绿茶对身体成分产生长期影响的原因，而且这些长期影响在适度体育活动的背景下可能也最为明显。然而，需要更多的研究来进一步阐明确切的作用机制，并将这些发现推广到非亚洲人群。
