Richard Weller: Could the sun be good for your heart?

Translator: Morton Bast Reviewer: Thu-Huong Ha

翻译人员: Emma Zhao 校对人员: Karen SONG

So, before I became a dermatologist,

在成为皮肤科医生之前

I started in general medicine,

我最初在一般内科（实习）

as most dermatologists do in Britain.

正如英国的大多数皮肤科医生所经历的那样

At the end of that time, I went off to Australia,

在实习结束前我去了澳大利亚

about 20 years ago.

那是大约20年前了。

What you learn when you go to Australia

去了澳大利亚

is the Australians are very competitive.

你就知道那里的人非常争强好胜

And they are not magnanimous in victory.

他们对于获胜可谓是斤斤计较

And that happened a lot:

这类事情经常发生：

"You pommies, you can't play cricket, rugby."

“你们英国佬不会打板球和橄榄球。”

I could accept that.

这个我能接受

But moving into work --

但换到工作中——

and we have each week what's called a journal club,

我们每周有一次期刊俱乐部的活动，

when you'd sit down with the other doctors

我跟别的医生们一起坐下来

and you'd study a scientific paper

研究一篇科学论文

in relation to medicine.

只要与医学相关

And after week one, it was about cardiovascular mortality,

第一个星期后，课题是关于心血管疾病的死亡率，

a dry subject -- how many people die of heart disease,

这很枯燥—— 多少人死于心脏病，

what the rates are.

死亡率是多少。

And they were competitive about this:

他们就抬杠说

"You pommies, your rates of heart disease are shocking."

“你们英国佬的心脏病率令人震惊。”

And of course, they were right.

当然，他们没错

Australians have about a third less heart disease than we do --

澳大利亚人的心脏病发病率比我们少三分之一

less deaths from heart attacks, heart failure, less strokes --

心脏病、心率衰竭、以及中风等病致死的概率也低

they're generally a healthier bunch.

他们（跟英国人比）是个更健康的人群

And of course they said this was because of

当然他们说这是因为

their fine moral standing, their exercise,

澳大利人道德高尚，喜爱运动

because they're Australians and we're weedy pommies, and so on.

因为他们是澳大利亚人，而我们是瘦弱的英国佬，等等。

But it's not just Australia that has better health than Britain.

但是不只是澳大利亚人比英国人健康。

Within Britain, there is a gradient of health --

在英国内部，健康也是有梯度的

and this is what's called standardized mortality,

这就是所谓的标准化死亡率

basically your chances of dying.

大致来说就是你死亡的概率

This is looking at data from the paper about 20 years ago,

论文引用的是20年前的数据

but it's true today.

在今天也适用

Comparing your rates of dying 50 degrees north --

对比北纬50度以北地区的死亡率

that's the South, that's London and places --

这是南方的伦敦和周边地区

by latitude, and 55 degrees --

北纬55度

the bad news is that's here, Glasgow.

这里情况不太好，是格拉斯哥

I'm from Edinburgh. Worse news, that's even Edinburgh.

我来自爱丁堡 。更糟的是，这里也有爱丁堡 。

(Laughter)

（笑声）

So what accounts for this horrible space here

是什么导致了这些地方的数据如此恐怖

between us up here in southern Scotland

在苏格兰南部

and the South?

和英格兰南部之间？

Now, we know about smoking,

现在，我们知道愿意包括吸烟、

deep-fried Mars bars, chips -- the Glasgow diet.

油炸的巧克力棒、薯片——这些都是格拉斯哥的饮食。

All of these things.

所有这些都是。

But this graph is after taking into account

但这张图是综合考虑了

all of these known risk factors.

所有这些已知风险因素的

This is after accounting for smoking, social class, diet,

排除了吸烟，社会地位，饮食，

all those other known risk factors.

以及其他所有已知的危险因素的影响

We are left with this missing space

这里有个空白区域

of increased deaths the further north you go.

越往北，死亡率越高

Now, sunlight, of course, comes into this.

现在，日照这个因素参与了进来

And vitamin D has had a great deal of press,

媒体有过大量关于维生素D的报道

and a lot of people get concerned about it.

许多人也开始关注

And we need vitamin D. It's now a requirement that children have a certain amount.

我们需要维生素D。现在对儿童每天的摄入量有所规定。

My grandmother grew up in Glasgow,

我祖母在格拉斯哥长大

back in the 1920s and '30s when rickets was a real problem

在20世纪二三十年代，佝偻病是个大问题

and cod liver oil was brought in.

鱼肝油被采用，

And that really prevented the rickets that used to be common in this city.

真正起到了预防佝偻病这种常见病的作用

And I as a child was fed cod liver oil by my grandmother.

小时候，祖母就给我吃过。

I distinctly -- nobody forgets cod liver oil.

无疑，没人会忘记鱼肝油。

But an association: The higher people's blood levels of vitamin D are,

可是有一个关联：血液里维生素D越高的人

the less heart disease they have, the less cancer.

患心脏病和癌症的几率越低

There seems to be a lot of data suggesting that vitamin D is very good for you.

有很多数据标明维生素D对人体有益。

And it is, to prevent rickets and so on.

它会预防佝偻病，等等。

But if you give people vitamin D supplements,

但如果你给人们维生素D补充剂，

you don't change that high rate of heart disease.

并不会改变心脏病的高发率。

And the evidence for it preventing cancers is not yet great.

它预防癌症的证据还不太具说服力

So what I'm going to suggest is that vitamin D is not the only story in town.

我的想法是，维生素D不是唯一的影响因素

It's not the only reason preventing heart disease.

它不是预防心脏病的唯一原因。

High vitamin D levels, I think, are a marker for sunlight exposure,

维生素D高，是常晒太阳的结果

and sunlight exposure, in methods I'm going to show,

我将要说明，多晒太阳

is good for heart disease.

能减少患心脏病的风险

Anyway, I came back from Australia,

不管怎样，我从澳大利亚回来了，

and despite the obvious risks to my health, I moved to Aberdeen.

我冒着生命危险搬到了阿伯丁

(Laughter)

（笑声）

Now, in Aberdeen, I started my dermatology training.

现在，在阿伯丁，我开始进行皮肤科的培训

But I also became interested in research,

可我也对研究感兴趣，

and in particular I became interested in this substance, nitric oxide.

特别是对一氧化氮这种物质感兴趣。

Now these three guys up here,

这三个人

Furchgott, Ignarro and Murad,

弗奇戈特、伊格纳罗和穆拉德

won the Nobel Prize for medicine back in 1998.

是1998年诺贝尔医学奖的得主

And they were the first people to describe

他们是最早来描述

this new chemical transmitter, nitric oxide.

这种新的化学传递物——一氧化氮——的人

What nitric oxide does is it dilates blood vessels,

一氧化氮会扩张血管，

so it lowers your blood pressure.

降低血压。

It also dilates the coronary arteries, so it stops angina.

它也能扩张冠状动脉，从而缓解心绞痛。

And what was remarkable about it

它与众不同的是

was in the past when we think of chemical messengers within the body,

过去当我们想到体内的化学信使时，

we thought of complicated things like estrogen and insulin,

我们会想到一些复杂的诸东西，如雌激素、胰岛素、

or nerve transmission.

或神经传导。

Very complex processes with very complex chemicals

非常复杂的流程伴有非常复杂的化学物质

that fit into very complex receptors.

存在于非常复杂的受体中。

And here's this incredibly simple molecule,

这是个非常简单的分子，

a nitrogen and an oxygen that are stuck together,

一个氮和一个氧粘在一起，

and yet these are hugely important for [unclear] our low blood pressure,

但这些对我们的维持较低的血压至关重要，

for neurotransmission, for many, many things,

它作用于神经传递和许多许多东西，

but particularly cardiovascular health.

尤其是心血管健康。

And I started doing research, and we found, very excitingly,

我们开始研究，并且非常激动地发现，

that the skin produces nitric oxide.

皮肤会生成一氧化氮。

So it's not just in the cardiovascular system it arises.

所以它不只是在心血管系统中才出现

It arises in the skin.

它在皮肤上也出现。

Well, having found that and published that,

将这个发现发表之后

I thought, well, what's it doing?

我就想，它在干啥呢？

How do you have low blood pressure in your skin?

你皮肤上怎么能有低血压呢？

It's not the heart. What do you do?

不是心脏。你是干啥呢？

So I went off to the States, as many people do if they're going to do research,

于是我去了美国，很多人都去美国做研究

and I spent a few years in Pittsburgh. This is Pittsburgh.

我在匹斯堡呆了几年，这就是匹斯堡。

And I was interested in these really complex systems.

我对这些超级复杂的系统感兴趣。

We thought that maybe nitric oxide affected cell death,

我们认为也许一氧化氮影响细胞死亡，

and how cells survive, and their resistance to other things.

影响细胞存活，也影响细胞的免疫

And I first off started work in cell culture, growing cells,

我先开始研究细胞文化，细胞生长

and then I was using knockout mouse models --

接着用被击昏了的老鼠作为模特

mice that couldn't make the gene.

那些老鼠不能生产基因。

We worked out a mechanism, which -- NO was helping cells survive.

我们研究出一个机理：一氧化氮帮助细胞存活

And I then moved back to Edinburgh.

后来我搬回爱丁堡。

And in Edinburgh, the experimental animal we use is the medical student.

在爱丁堡，我的实验动物是医学院学生。

It's a species close to human,

是接近人类的一个物种，

with several advantages over mice:

跟老鼠相比有以下几个好处：

They're free, you don't shave them, they feed themselves,

不用付费，不用给他们剃毛，不用喂养他们

and nobody pickets your office saying,

没人查你的办公室，还要说：

"Save the lab medical student."

“管好你实验室的医科学生。”

So they're really an ideal model.

所以说，他们真是理想的模特。

But what we found

但我们发现

was that we couldn't reproduce in man the data we had shown in mice.

我们不能在人身上复制出在老鼠身上得到的数据。

It seemed we couldn't turn off the production

看来我们不能停止

of nitric oxide in the skin of humans.

人体皮肤产生一氧化氮

We put on creams that blocked the enzyme that made it,

我们涂上乳液就能阻挡制造它的酶，

we injected things. We couldn't turn off the nitric oxide.

我们能注射药品。但我们无法停住一氧化氮。

And the reason for this, it turned out, after two or three years' work,

经过两三年的工作，我们终于找出了原因，

was that in the skin we have huge stores

我们皮肤里大量储存的并非一氧化氮

not of nitric oxide, because nitric oxide is a gas,

因为一氧化氮是气体

and it's released -- (Poof!) -- and in a few seconds it's away,

它要挥发的——（噗！) ——几秒钟就没影了，

but it can be turned into these forms of nitric oxide --

但一氧化氮能转化成

nitrate, NO3; nitrite, NO2; nitrosothiols.

硝酸盐、硝酸盐、亚硝酸盐、二氧化氮、亚硝基硫醇。

And these are more stable,

这些形式更稳定

and your skin has got really large stores of NO.

你的皮肤就得到了大量的一氧化氮

And we then thought to ourselves, with those big stores,

我们就寻思

I wonder if sunlight might activate those stores

阳光是否会活化这大量的一氧化氮

and release them from the skin,

将它们从皮肤中释放出来

where the stores are about 10 times as big as what's in the circulation.

这些一氧化氮的存量10倍于参与新陈代谢的一氧化氮量

Could the sun activate those stores into the circulation,

太阳能不能激活这些存量让它们参与新陈代谢，

and there in the circulation do its good things for your cardiovascular system?

从而作用于心血管系统呢？

Well, I'm an experimental dermatologist,

我呢，是个实验皮肤科医生，

so what we did was we thought

所以我们想到

we'd have to expose our experimental animals to sunlight.

应该让实验动物多晒太阳

And so what we did was we took a bunch of volunteers

于是，我们找来了一群志愿者

and we exposed them to ultraviolet light.

让他们接受紫外线照射

So these are kind of sunlamps.

这些是太阳灯。

Now, what we were careful to do was,

这里我们要小心

vitamin D is made by ultraviolet B rays

维生素D是通过中波紫外线（UVB）射线生成的

and we wanted to separate our story from the vitamin D story.

而我们想排除维生素D的干扰

So we used ultraviolet A, which doesn't make vitamin D.

所以，我们使用了不生成维生素D的长波紫外线（UVA）

When we put people under a lamp

我们对受试者进行照射

for the equivalent of about 30 minutes of sunshine in summer in Edinburgh,

强度相当于暴露在爱丁堡夏日阳光中30分钟

what we produced was, we produced a rise

结果是我们得到了

in circulating nitric oxide.

新陈代谢中一氧化氮的提升

So we put patients with these subjects under the UV,

我们让心血管病的患者接受紫外线照射

and their NO levels do go up,

他们的一氧化氮水平上升了

and their blood pressure goes down.

而他们的血压下降了

Not by much, as an individual level,

就个人而言不算多

but enough at a population level

但对于整个人群而言有显著意义

to shift the rates of heart disease in a whole population.

足以改变整个人群的心脏病患病率

And when we shone UV at them,

给他们照射紫外线

or when we warmed them up to the same level as the lamps,

或者使他们的皮肤太阳灯的温度那样温暖

but didn't actually let the rays hit the skin, this didn't happen.

但不让光线接触皮肤，同样的结果就不会发生

So this seems to be a feature of ultraviolet rays hitting the skin.

这似乎说明了其中关键在于紫外线要接触到皮肤

Now, we're still collecting data.

我们至今仍在收集数据

A few good things here:

有几样好的发现：

This appeared to be more marked in older people.

这在年长者身上效果更明显

I'm not sure exactly how much.

我不确定具体的数量

One of the subjects here was my mother-in-law,

其中一个被试是我的岳母大人

and clearly I do not know her age.

很显然我不太清楚她的年龄

But certainly in people older than my wife,

但肯定比我太太年纪要大

this appears to be a more marked effect.

在她身上效果更明显

And the other thing I should mention

我要提到的另一点是

was there was no change in vitamin D.

在整个过程中维生素D并没有发生变化

This is separate from vitamin D.

维生素D的影响是被分离的

So vitamin D is good for you -- it stops rickets,

维生素D对人有益——它预防佝偻病

it prevents calcium metabolism, important stuff.

还能预防钙流失，是很重要的微量元素

But this is a separate mechanism from vitamin D.

但（我们研究的）这是一个与维生素D相分离的机制

Now, one of the problems with looking at blood pressure

现今在血压的问题上有一点要注意

is your body does everything it can

就是你的身体会竭尽所能

to keep your blood pressure at the same place.

去把血压维持在同一个水平

If your leg is chopped off and you lose blood,

如果你的腿被剁断，你会失血，

your body will clamp down, increase the heart rate,

你的身体会施加压力，增加心跳，

do everything it can to keep your blood pressure up.

来尽可能地维持你的正常血压。

That is an absolutely fundamental physiological principle.

这是一个绝对的基本生理原则。

So what we've next done

所以我们接下来做的

is we've moved on to looking at blood vessel dilatation.

就是转而研究血管扩张

So we've measured -- this is again,

我们测试了同一批（实验动物）

notice no tail and hairless, this is a medical student.

注意他们没有尾巴也没有皮毛，这是个医科学生。

In the arm, you can measure blood flow in the arm

你测量手臂上的血流

by how much it swells up as some blood flows into it.

测量血流通过时血管扩张了多少

And what we've shown is that doing a sham irradiation --

这里显示的是在做假射机

this is the thick line here --

这里有条粗线

this is shining UV on the arm so it warms up

紫外线照射到手臂上，皮肤升温

but keeping it covered so the rays don't hit the skin.

但我们盖住皮肤，所以紫外线就接触不到了

There is no change in blood flow, in dilatation of the blood vessels.

血流量没有变化，血管也没有扩张

But the active irradiation,

但如果让紫外线接触皮肤

during the UV and for an hour after it,

在紫外线照射期间及照射后一小时

there is dilation of the blood vessels.

血管都有所扩张

This is the mechanism by which you lower blood pressure,

这就是降低血压的机制

by which you dilate the coronary arteries also,

你的冠状动脉也扩张了

to let the blood be supplied with the heart.

给心脏提供更多的血液

So here, further data that ultraviolet -- that's sunlight --

这里有更多有关紫外线——也就是太阳光的作用

has benefits on the blood flow and the cardiovascular system.

数据显示紫外线有益于血流和心血管系统。

So we thought we'd just kind of model --

我们认为我们只是一种模型--

Different amounts of UV hit different parts of the Earth at different times of year,

不同时节照射到不同地域的紫外线是不等的

so you can actually work out those stores of nitric oxide --

所以，你其实可以

the nitrates, nitrites, nitrosothiols in the skin --

将皮肤里的硝酸盐、亚硝酸盐、还有亚硝基硫醇

cleave to release NO.

分解得到一氧化氮

Different wavelengths of light have different activities of doing that.

不同波长的光产生不同的反应

So you can look at the wavelengths of light that do that.

所以你可以去检视光波

And you can look -- So, if you live on the equator, the sun comes straight overhead,

如果你住在赤道地区，太阳光垂直射入

it comes through a very thin bit of atmosphere.

薄薄的大气

In winter or summer, it's the same amount of light.

无论冬夏，光照的量是相同的

If you live up here, in summer

如果你住在（高纬度地区）

the sun is coming fairly directly down,

太阳光在夏季几乎是直射的

but in winter it's coming through a huge amount of atmosphere,

而在冬季就会斜穿厚厚的大气

and much of the ultraviolet is weeded out,

很多紫外线无法到达地面

and the range of wavelengths that hit the Earth

而到达地面的波长范围

are different from summer to winter.

夏天和冬天是不同的

So what you can do is you can multiply those data

你可以把这些数据

by the NO that's released

乘上一氧化氮的释放量

and you can calculate how much nitric oxide

你就可以算出有多少一氧化氮

would be released from the skin into the circulation.

从皮肤里释放，参与到新陈代谢中去

Now, if you're on the equator here --

如果你在赤道地区

that's these two lines here, the red line and the purple line --

也就是这两条红色和紫色的线

the amount of nitric oxide that's released is the area under the curve,

线下方的区域代表一氧化氮的释放量

it's the area in this space here.

也就是这片区域

So if you're on the equator, December or June,

所以如果你在赤道地区，不管是12月份还是6月份

you've got masses of NO being released from the skin.

你的皮肤里都能释放大量的一氧化氮

So Ventura is in southern California.

南加州有个地方叫文图拉

In summer, you might as well be at the equator.

你在夏天能得到相当于赤道地区的日照

It's great. Lots of NO is released.

这太棒了，释放了很多的一氧化氮

Ventura mid-winter, well, there's still a decent amount.

文图拉的隆冬，结果也不错

Edinburgh in summer, the area beneath the curve is pretty good,

爱丁堡的夏季，曲线以下的区域也还行

but Edinburgh in winter, the amount of NO that can be released

可以一到冬季，一氧化氮

is next to nothing, tiny amounts.

几乎就不释放了

So what do we think?

我们如何看待这个结果？

We're still working at this story,

我们仍然在研究

we're still developing it, we're still expanding it.

我们仍然在发掘和扩展

We think it's very important.

我们认为这项研究非常重要

We think it probably accounts for a lot of the north-south health divide within Britain,

我们认为这项研究能解释英国南北部很多的健康问题的差异

It's of relevance to us.

这是与我们切实相关的

We think that the skin --

我们认为人的皮肤

well, we know that the skin has got very large stores

我们知道人的皮肤上有很多

of nitric oxide as these various other forms.

以不同形式存在的一氧化氮

We suspect a lot of these come from diet,

我们猜想其中有很多来自于饮食

green leafy vegetables, beetroot, lettuce

绿叶蔬菜，甜菜根、还有生菜

has a lot of these nitric oxides that we think go to the skin.

含有很多的一氧化氮，我们认为它最终来到皮肤

We think they're then stored in the skin,

并且贮存在皮肤里

and we think the sunlight releases this

我们认为太阳光能释放这些一氧化氮

where it has generally beneficial effects.

起到很多有益的作用

And this is ongoing work, but dermatologists --

这个研究还在进行之中，可皮肤科医生们——

I mean, I'm a dermatologist.

我就是一名皮肤科医生

My day job is saying to people, "You've got skin cancer,

白天的工作中我要对病人说，“你得了皮肤癌，

it's caused by sunlight, don't go in the sun."

是阳光引起的， 别去晒太阳。”

I actually think a far more important message

其实我认为还有更重要的一则讯息

is that there are benefits as well as risks to sunlight.

就是晒太阳既有益处，也有风险

Yes, sunlight is the major alterable risk factor for skin cancer,

没错，阳光是引发皮肤癌的一个主要风险变量

but deaths from heart disease are a hundred times higher

但是死于心脏病的人数

than deaths from skin cancer.

是死于皮肤癌的一百倍

And I think that we need to be more aware of,

我们需要加深对此的了解

and we need to find the risk-benefit ratio.

我们还需要找到其中的风险效益比

How much sunlight is safe,

晒多少太阳是安全的？

and how can we finesse this best for our general health?

如何掌握其中分寸来增进大家普遍的健康？

So, thank you very much indeed.

非常感谢大家。

(Applause)

（掌声）