第13期冬天穿暖和能避免心脏病发作 - 英语阅读

Wrap up Warm to Avoid Heart Attacks
冬天穿暖和能避免心脏病发作
When it's cold we turn up the central heating.
当天气寒冷时，我们会打开中央供暖系统。
Our bodies do the same-burning brown fat to produce extra heat and
我们的身体也是一样，我们会燃烧褐色脂肪来产生额外的热量，
keep us warm.
以保持我们身体的温暖。
But this internal heating system may have a dangerous side effect.
但是这种内部加热系统可能会有危险的副作用。
"Brown fat has always been considered to be good fat." says Yihai Cao
卡罗林斯卡医学院的曹义海说:
at the Karolinska Institute.
“褐色脂肪一直被认为是不错的脂肪。”
Since it turns the energy obtained from food into heat, brown fat
由于事实证明热量是由食物中所获得的能量转化而来的，所以褐色脂肪
thought to be one of the keys to weight loss.
被认为是减肥的关键之一。
Cao and colleagues wanted to investigate its role in atherosclerosis-the
曹义海和他的同事们想探讨褐色脂肪在动脉硬化中所扮演的角色，
build-up of fatty deposits in blood vessels.
动脉硬化指的是脂肪在血管中的沉积。
First, the team created genetically modified mice that were especially
首先，研究团队创造出了一种转基因老鼠，
prone to atherosclerosis. 。
这些老鼠特别容易发生动脉硬化。
At eight weeks old, they split the mice into two groups.
在老鼠8周大的时候，研究人员把老鼠分成了两组。
Some mice were kept for a further eight weeks at 30°C-a temperature
一组老鼠在30°C的温度下继续待8周，
that mice find comfortable-while the rest were kept at 4℃.
这个温度会让老鼠感觉很舒适，而另一组老鼠将待在4°C的温度下。
Mice exposed to the cold converted more white fat to brown and the
暴露于寒冷环境下的老鼠能将更多的白色脂肪转化成褐色脂肪，
production of low-density lipoprotein (LDL) was accelerated, leading
加快生产低密度的脂蛋白，
to a greater build-up of fatty deposits.
从而导致更多脂肪的沉积。
The mice kept in the cold also had deposits in their blood vessels
同时，在寒冷环境下饲养的老鼠的血管中也会有沉积，
that were more likely to break off and cause blockages-a major
这更容易造成血管的中断，导致堵塞，
cause of heart attack and stroke.
这是心脏病发作和中风的一个重要原因。
To test whether the effect was specifically linked to heat generation,
为了测试这种结果是否与产生的热量有关，
the team next created atherosclerosis-prone mice that were unable to
研究人员接下来创造出易发生动脉硬化的老鼠，它们无法
use their brown fat to produce heat.
使用褐色脂肪产生热量。
These mice were completely protected from the increased production
这些老鼠完全在生产量提高的低密度脂蛋白的保护下，
of LDL and consequent arterial problems.
结果产生了动脉问题。
But Andrew Whittle at the University of Cambridge notes that mice
但是剑桥大学的安德鲁·惠特尔指出，老鼠
kept in the cold will eat more food, which might also contribute to
在寒冷的环境中会吃更多的食物，这可能也有助于
the extra fatty deposits.
多余脂肪的沉积。
Until recently we did not know adult humans had brown fat at all,
曹义海说，直到最近，我们根本不知道成年人体内是否有褐色脂肪，
he says, and we are still learning what it does.
我们仍然在研究其作用。