广场舞献给祖国的歌:绿茶减肥效果有多大？

根据美国的一项研究报告，我们需要清理下大众读物中有关绿茶（无论是绿茶胶囊的还是在冲泡在水杯里的）对胆固醇的作用的一些观点。

  这项研究分析了20个实验，分别检测了绿茶本身和绿茶胶囊中含有的一种叫儿茶素的物质，这种物质曾经被认为可以减少人体肠道中胆固醇的吸收。

  这项发现被刊登在 美国膳食协会的会刊 ，表明绿茶可以减少人体总胆固醇含量的5％到6％或者更高。相对于胶囊或者其它治疗方法，绿茶会导致”坏”的低密度脂蛋白胆固醇水平。

  相对于瓶装绿茶，在水杯中冲泡的绿茶拥有更持久的效果，尽管这些效果的整体水平相对较小，资深研究者Olivia Phung说，他是加利福尼亚州西部健康科学大学的助理教授。

"If someone is already taking medication for their cholesterol, they should stick with it and not try to trade it for green tea, either capsules or the beverage," says Phung.

“对于那些已经采取药物胶囊治疗胆固醇的人，他们应该坚持既有的疗法，不要试着去采用绿茶，无论是饮料还是绿茶胶囊，” Phung说。

But adding green tea to your diet could be one way to further improve cholesterol numbers, she says. 

但是如果在饮食中添加绿茶是一种有效减少胆固醇数量的方法。

The researchers, however, found no strong evidence that green tea boosted 'good' HDL cholesterol, or cut triglycerides, another type of blood fat.

但是研究者并未发现绿茶可以提高“好”的高密度脂蛋白胆固醇或者减少甘油三酸脂（另一种血液脂肪）的强有力的证明

The trials included in Phung's review involved a total of 1,415 adults.

这些实验包括Phung的评论，总共涉及了1415位成人。

Participants were randomly assigned to either use green tea every day, as a beverage or capsule, or be part of "control" groups that took placebo capsules, drank a low-catechin tea or downed water.

实验的参与者被随机分配到每天都服用绿茶饮料或胶囊制品的实验组和服用安慰剂胶囊和喝低儿茶素的茶或者更直接饮用水的控制组。

The trials lasted anywhere from three weeks to six months and the benefits seemed to be limited to people who already had high cholesterol when they entered the study.

实验随机在任意地方进行，持续了3周到6个月，发现似乎只有那些原本有高含量的胆固醇的人才有效果。

Overall, tea seemed more effective than capsules, though Phung said there isn't enough data to be sure that the beverage is better than the extract.

总体上说，茶的效果要好于胶囊制品，尽管Phung认为，目前没有足够的数据可以证明茶饮料比提取物的效果好。

Limitations

实验的局限

A number of clinical trials that examined whether green tea, or its extracts, can benefit people's cholesterol levels have reached mixed conclusions. Most of the trials have been small, making them less reliable.

一些少量的检验绿茶或者它的提取对人体胆固醇含量的影响的物临床试验指向了一个混乱的结果。大部分实验都非常的小规模，不具有可信度。

There are other questions too, including what dose of green tea catechins is ideal.

也有一些别的问题，包括多少剂量的绿茶儿茶素是理想的。

In the trials Phung's team studied, the researchers were unable to test for a 'dose-response' effect, which would have shown whether the cholesterol benefits increase as the catechin dose goes up.

在Phung的研究团队的实验中，研究者无法检测“剂量反应”效果，它可以表明胆固醇降低的效果是否会随着儿茶素剂量的增加而加强。

"We would really need to have some head-to-head studies comparing the different forms of green tea in order to show which ones work more effectively," says Phung.

“我们真地需要更进一步的研究，比较不同品种的绿茶，这样可以检测出哪种绿茶的更具效果，” Phung说。

As for side effects, green tea is considered safe in moderate amounts, though the drink and the extracts contain caffeine, which some people may need to avoid.

至于副作用，适量的绿茶是安全的。但是饮料和叫囊中还有咖啡因，对于有些人来说还是要避免接触的。

There have also been a few dozen cases of liver damage reported among people using green tea extracts, but it's not certain that the supplements are to blame.

在那些使用绿茶提取物的人群中，也报道了一些很少的对肝脏有损害的案例，但是这是不是这些补充剂的所为还尚待明确。