Today we’re talking about coffee.

今天我们来聊聊咖啡。

We hear a lot of conflicting findings about whether our favorite beverage is good or bad for our health.

关于我们最喜欢的饮料对我们的健康是好还是坏，我们听到了很多相互矛盾的发现。

But recently, an especially rigorous study came out that may finally answer some of our percolating questions.

但最近，一项特别严谨的研究问世，可能会回答一些流传已久的问题。

There’s a good chance that, right now, you’re sipping the very thing we’re talking about--coffee. It is one of the most widely consumed beverages in the world.

这是个好机会，现在，你慢酌浅饮的正在我们谈论的东西--咖啡。咖啡是世界饮用最广泛的饮料之一。

It’s true. Here in the U.S., the average person drank almost 89 gallons of coffee in 2016—more than soda, tea and juice combined.

这是事实。在美国，2016年平均每人喝下近89加仑的咖啡——超过了苏打水、茶和果汁的总和。

That’s a lot of java. Or joe, brew, or jitter juice, whatever you like to call it.

咖啡有很多别称，如java、joe、brew和jitter juice，随你怎么叫都可以。

Indeed. Do you drink coffee, Josh?

确实。你喝咖啡吗，乔希?

Actually I guess I’m one of the few people who doesn’t. I used to guzzle it, though—about 4 or 5 cups a day. But I gave it up a few years ago.

事实上，我想我是少数不喝咖啡的人之一。不过，我过去常常狂饮咖啡——一天大约4到5杯。但几年前我戒了。

Why? What happened?

为什么? 发生了什么事?

Honestly, my stomach started getting upset. I figured I could do without so much acid, you know?

老实说，我的胃开始不舒服。我觉得我得减少酸的摄入。

That totally makes sense. But personally, I’m not really functional until I’ve had my morning cup of coffee, and I don’t know if I could give that up.

这完全在理。但就我个人而言，我早上不喝咖啡，我是无法真正工作的，我不知道我是否能戒掉咖啡。

There are times when I catch the aroma from a coffee shop, and it just smells so good!

有时闻到咖啡店的香味，感觉太好闻了!

But listen, I’m still not sure coffee was causing my problems.

但注意，我还是无法确定是否是咖啡引起了我的问题。

It feels like every day there’s a new study telling us coffee is good for us or bad for us, for a whole bunch of different reasons.

感觉每天都有一项新的研究告诉我们，咖啡对我们要么有益要么有害，原因各不相同。

With all these conflicting messages, it can feel like whiplash.

所有这些相互矛盾的信息，感觉像是在互相鞭打。

Well, it turns out it’s actually really hard to study how coffee or any other food or drink affects our health.

嗯，事实证明，研究咖啡或任何其他食物或饮料如何影响我们的健康真的很难。

Most nutrition studies are observational studies, which compare health outcomes in people who happen to drink coffee to those who don’t.

大多数营养学研究都是观察性研究，将碰巧喝咖啡的人与不喝咖啡的人的健康状况进行比较。

But it’s impossible to rule out other variables that could affect what you’re trying to measure.

但是，这不可能排除其他可能影响你试图测量的变量。

Plus, you have to rely on people reporting what they consumed weeks or months after they drank it.

另外，你必须看看人们在喝下咖啡的几周或几个月后他们还喝了什么。

And most of us can’t even remember what we had for breakfast.

我们大多数人甚至不记得早餐吃了什么。

So, what’s the solution? Is there another way to study this?

那么，有什么解决方案呢? 有其他的研究方法吗?

Well, there is a way to be more objective. I talked to…

嗯，有一种更客观的方法。我采访了……

Gregory Marcus, Professor of Medicine and cardiologist at University of California, San Francisco.

格雷戈里·马库斯是加州大学旧金山分校的医学教授与心脏病专家。

Marcus and his colleagues took a different approach than most other coffee studies.

马库斯与同事采用了与大多数其他咖啡研究不同的方法。

Instead of just studying people who drank coffee or didn’t, he set up a randomized trial to study coffee’s impact on your heartbeat.

他没有仅仅研究喝咖啡或不喝咖啡的人，而是进行了一项随机试验研究咖啡对心跳的影响。

They were looking for abnormal heart rhythms called arrhythmias.

他们在寻找异常的心律，也就是心率不齐。

The topic comes up very frequently in my clinic, where patients with various arrhythmias will ask if they can consume coffee.

这个话题在我的诊所里经常出现，各类心律失常的病人会询问他们是否可以饮用咖啡。

There's this conventional wisdom that coffee increases the risk for heart rhythm disturbances or electrical problems with the heart, which is my clinical subspecialty.

传统观点认为，咖啡会增加心律紊乱或心脏电活动紊乱的风险。心律紊乱是我的临床亚专业。

And yet, we and others in conducting recent observational studies generally have failed to find a clear association between coffee and arrhythmias.

然而，我们和其他人在最近进行的观察性研究中，普遍未能找到咖啡与心律失常之间的明确联系。

In their new study, Marcus and his colleagues randomly assigned 100 people to either drink or not drink coffee each day for a period of two weeks.

在新研究中，马库斯与同事随机对100人进行分配，让一部分人在两周的时间里每天喝咖啡，另一部分人每天不喝咖啡。

And they receive these instructions via text message, and they were randomly assigned to either go ahead and drink all the coffee you want, versus on other random days, avoid all caffeine today.

他们通过短信收到这些指示，他们被随机分配，要么继续喝想喝的所有咖啡，要么在任意时间里避免摄入任何咖啡因。

They had participants wear a heart monitor, a FitBit and a continuous glucose monitor.

他们让参与者佩戴FitBit心脏监测器与动态血糖监测器。

They also had them download an app on their phone that collected GPS location data so the researchers could see when people were actually visiting coffee shops.

他们还让参与者在手机上下载了一个收集GPS定位数据的应用程序，这样研究人员就可以看到他们什么时候去了咖啡店。

With the heart monitors, what were they looking at?

他们用心脏监测器观察什么?

They were measuring two things: the number of what are called premature atrial contractions and premature ventricular contractions.

他们测量了两个数据：房性期前收缩（房性早搏）次数与室性期前收缩(室性早搏)次数。

It's very common for everyone to have an early beat arising from the upper chambers of the heart called premature atrial contractions, or PACs, once in a while.

心脏上腔(左右心房)的早搏于每个人而言很常见，这种现象被称为房性期前收缩(简称PAC)。

But research has shown that having too many of these beats puts you at risk of atrial fibrillation, which is a dangerously irregular, rapid heart beat.

但研究表明，这种心跳次数过多会有患房颤的风险，这是一种危险的不规则、快速的心跳。

This is associated with a very high risk for stroke, dementia, and death.

这与中风、痴呆、死亡的高风险相关。

Then there’s the other kind of irregular heartbeat:

还有另一种不规则的心跳:

Premature ventricular contractions are early beats that arise from the lower chambers of the heart.

室性期前收缩是由心脏下腔(左右心室)引起的早期心跳。

Again, we all have those sometimes, but those with more are at higher risk of developing heart failure or a weakening of the heart.

同样，我们有时都会有这样的情况，但那些经历更多室性期前收缩的人患心力衰竭或心脏衰竭的风险更高。

They found that drinking coffee did not result in more premature atrial contractions—the early heart beats associated with atrial fibrillation.

他们发现，喝咖啡并不会导致更多的房性期前收缩——早搏与房颤有关。

That’s good news for people who were worried about that.

这对担心这个问题的人来说是个好消息。

That is reassuring. But what about the other bad beats, the premature contractions in the heart’s lower chambers?

这就让人放心了。那其他有害心跳，发生在心脏下腔的期前收缩(室性期前收缩)呢?

Those were slightly more common on days when people were told to drink coffee, or on days when they drank more coffee—but not enough to be really worrisome.

在参与者被告知要喝咖啡或喝更多咖啡的日子里，这种早搏情况稍微常见一些，但并不足以让人真正担心。

And that’s not all they found.

这还不是他们发现的全部。

Coffee consumption was also associated with a higher number of daily steps.

喝咖啡也与每天走更多的步数有关。

On days when people drank coffee—and the more coffee they drank—the more steps they took.

在人们喝咖啡的日子里，他们喝的咖啡越多，他们走的步数就越多。

来源：Scientific American