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

Translator: Morton Bast Reviewer: Thu-Huong Ha

Translator: Serv. de Norm. Lingüística U. de Santiago de Compostela Reviewer: Xusto Rodriguez

So, before I became a dermatologist,

Antes de facerme dermatólogo,

I started in general medicine,

comecei na medicina xeral,

as most dermatologists do in Britain.

como fan moitos dermatólogos en Gran Bretaña.

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

Ao rematar, fun a Australia,

about 20 years ago.

hai case vinte anos.

What you learn when you go to Australia

Cando marchas a Australia

is the Australians are very competitive.

aprendes que os australianos son moi competitivos.

And they are not magnanimous in victory.

E non son magnánimos nas vitorias.

And that happened a lot:

E iso pasaba moito:

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

"Ingleses, non sabedes xogar ao cricket, rugby...".

I could accept that.

Podía aceptar iso.

But moving into work --

No relacionado ao traballo,

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

temos semanalmente un club de lectura,

when you'd sit down with the other doctors

onde sentas cos outros médicos

and you'd study a scientific paper

e estudas unha publicación científica

in relation to medicine.

que teña relación coa medicina.

And after week one, it was about cardiovascular mortality,

O segundo encontro foi sobre a mortalidade cardiovascular,

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

un tema complicado.

As mortes por enfermidades cardíacas,

what the rates are.

cales son as taxas.

And they were competitive about this:

E eran competitivos sobre isto:

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

"Ingleses, as vosas taxas de cardiopatías son tremendas."

And of course, they were right.

E certamente tiñan razón.

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

Os australianos teñen un terzo menos de cardiopatías ca nós

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

--menos mortes por ataques ao corazón, por insuficiencias cardíacas ou infartos.

they're generally a healthier bunch.

Adoitan ser máis sans.

And of course they said this was because of

E claro, dicían que isto era pola súa superior integridade moral

their fine moral standing, their exercise,

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

porque eles son australianos e nós frouxos inglesiños.

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

Pero non é só que teñan mellor saúde ca Gran Bretaña.

Within Britain, there is a gradient of health --

En Gran Bretaña hai un gradiente de saúde,

and this is what's called standardized mortality,

isto chámase mortalidade estandarizada,

basically your chances of dying.

é dicir, as probabilidades de morrer.

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

Estes son datos dos xornais de hai vinte anos,

but it's true today.

mais segue sendo certo hoxe.

Comparing your rates of dying 50 degrees north --

Se comparamosas taxas de mortalidade a 50 graos norte

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

--esa frecha sinala o sur, Londres e contorna--

by latitude, and 55 degrees --

e a 55º norte,

the bad news is that's here, Glasgow.

a mala noticia é que Glasgow é isto de aquí.

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

Eu son de Edimburgo. Peores novas aínda en Edimburgo.

(Laughter)

(Risos)

So what accounts for this horrible space here

Entón, que é o que pasa neste terrible espazo,

between us up here in southern Scotland

aquí entre nós, no sur de Escocia,

and the South?

e o sur?

Now, we know about smoking,

Xa sabemos o dos fumadores,

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

as barriñas Mars fritidas, as patacas... a dieta de Glasgow.

All of these things.

Todo iso.

But this graph is after taking into account

Mais esta gráfica xa ten en conta,

all of these known risk factors.

todos estes factores de risco coñecidos.

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

Isto xa ten en conta fumadores, clase social, dieta,

all those other known risk factors.

todos eses factores de risco coñecidos.

We are left with this missing space

Quédanos este espazo perdido,

of increased deaths the further north you go.

de mortes crecentes canto máis vaias ao norte.

Now, sunlight, of course, comes into this.

A luz do sol, por suposto, inflúe.

And vitamin D has had a great deal of press,

A vitamina D tivo moi mala prensa,

and a lot of people get concerned about it.

e moita xente preocúpase por ela.

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

E precisamos a vitamina D.

Agora é unha obriga que os nenos teñan unha cantidade concreta.

My grandmother grew up in Glasgow,

Miña avoa medrou en Glasgow, alá polo 1920 e os anos 30,

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

cando o raquitismo era un gran problema

and cod liver oil was brought in.

e chegou o aceite de fígado de bacallau.

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

Iso solucionou o raquitismo que era tan común nesta cidade.

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

A min, de pequeno, miña avoa fíxome tomar este aceite.

I distinctly -- nobody forgets cod liver oil.

Obviamente... ninguén esquece nunca o aceite de fígado de bacallau.

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

Unha cuestión: canto máis altos son os niveis de vitamina D na xente,

the less heart disease they have, the less cancer.

menos cardiopatías e menos cancros teñen.

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

Hai moitas estatísticas que indican que a vitamina D é boa para nós.

And it is, to prevent rickets and so on.

E así é, para previr raquitismo e iso.

But if you give people vitamin D supplements,

Pero se lle dás á xente suplementos de vitamina D,

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

non cambias esa alta taxa de cardiopatías.

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

E as probas de que preveña o cancro aínda non son definitivas.

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

Entón o que vou suxerir é que a vitamina D non é o único importante aquí.

It's not the only reason preventing heart disease.

Non é a única razón que prevén unha cardiopatía.

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

Niveis altos de vitamina D, penso eu, son indicadores da exposición á luz solar,

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

e a exposición á luz solar,

nos mecanismos que vou ensinar, é boa para as enfermidades do corazón.

is good for heart disease.

Anyway, I came back from Australia,

En calquera caso, volvín de Australia

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

e, a pesar dos obvios riscos para a miña saúde, mudeime a Aberdeen,

(Laughter)

(Risos)

Now, in Aberdeen, I started my dermatology training.

Agora, en Aberdeen, comecei a miña formación como dermatólogo.

But I also became interested in research,

Pero tamén me interesei na investigación,

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

e sobre todo nesta substancia, o óxido nítrico (NO).

Now these three guys up here,

Estes tres tipos de aquí, Furchfott, Ignarro e Murad,

Furchgott, Ignarro and Murad,

won the Nobel Prize for medicine back in 1998.

gañaron o Premio Nobel de Medicina en 1998.

And they were the first people to describe

Foron as primeiras persoas en describir

this new chemical transmitter, nitric oxide.

este novo transmisor químico, o óxido nítrico.

What nitric oxide does is it dilates blood vessels,

O óxido nítrico (NO) dilata os vasos sanguíneos,

so it lowers your blood pressure.

así baixa a túa presión sanguínea.

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

Tamén dilata as arterias coronarias, co que detén as anxinas.

E o que é máis impresionante del

And what was remarkable about it

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

é que no pasado, cando pensabamos en mensaxeiros químicos dentro do corpo,

we thought of complicated things like estrogen and insulin,

pensabamos en cousas complicadas como estróxeno e insulina,

or nerve transmission.

ou a transmisión nerviosa.

Very complex processes with very complex chemicals

Procesos moi complexos con substancias químicas moi complexas

that fit into very complex receptors.

que encaixan en receptores moi complexos.

And here's this incredibly simple molecule,

E velaquí esta molécula incriblemente simple,

a nitrogen and an oxygen that are stuck together,

un nitróxeno e un osíxeno pegados,

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

que son tamén moi importantes para manter baixa a presión arterial,

for neurotransmission, for many, many things,

para a neurotransmisión e para outras moitas cousas,

but particularly cardiovascular health.

especialmente para a saúde cardiovascular.

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

Comecei a investigar e descubrimos, de xeito moi emocionante,

that the skin produces nitric oxide.

que a pel produce óxido nítrico.

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

Así que non xorde só no sistema cardiovascular.

It arises in the skin.

Xorde na pel.

Well, having found that and published that,

Despois de descubrilo e publicalo

I thought, well, what's it doing?

pensei, que é o que fai?

How do you have low blood pressure in your skin?

Como tes baixa presión arterial na pel?

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

Non é o corazón. Que facemos logo?

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

Marchei aos Estados Unidos, como fai moita xente que quere investigar,

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

e pasei uns poucos anos en Pittsburgh. Velaí Pittsburgh.

And I was interested in these really complex systems.

Interesábanme estes sistemas tan complexos.

We thought that maybe nitric oxide affected cell death,

Pensabamos que o óxido nítrico podía afectar á morte das células,

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

a como sobreviven e á súa resistencia a máis cousas.

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

Entón comecei a traballar no cultivo de células,

and then I was using knockout mouse models --

e usei modelos de rato "knockout"

mice that couldn't make the gene.

--ratos con xenes desactivados--

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

Traballamos nun mecanismo en que o NO lles axudaba ás células a sobrevivir.

And I then moved back to Edinburgh.

Daquela mudeime outra vez a Edimburgo.

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

Alí o animal de laboratorio que usamos foi o estudante de medicina

It's a species close to human,

É unha especie próxima ao ser humano,

with several advantages over mice:

con moitas vantaxes sobre os ratos:

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

son libres, non os tes que afeitar nin alimentar,

and nobody pickets your office saying,

e ninguén se manifesta diante do despacho dicindo

"Save the lab medical student."

"Salva ao estudante de medicina de laboratorio".

So they're really an ideal model.

Polo que son un coello de indias ideal.

But what we found

Atopamos que non podiamos reproducir en persoas os datos recollidos dos ratos.

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

It seemed we couldn't turn off the production

Parecía que non podiamos frear a xeración do óxido nítrico na pel humana.

of nitric oxide in the skin of humans.

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

Puxémoslles cremas para bloquear o encima que o xeraba, inxectámoslles cousas.

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

Non podiamos parar o óxido nítrico.

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

A razón era --descubrímolo despois de dous ou tres anos de traballo--

was that in the skin we have huge stores

que na pel temos uns enormes almacéns,

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

non de óxido nítrico, que é un gas,

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

e logo de liberado... puf! Nuns segundos desaparece,

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

mais pode encontrarse noutras formas:

nitrate, NO3; nitrite, NO2; nitrosothiols.

nitrato (NO3), nitrito (NO2), tionitritos.

And these are more stable,

Estes son máis estables,

and your skin has got really large stores of NO.

e a túa pel ten enormes almacéns de NO.

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

Despois pensamos, se estes almacéns,

I wonder if sunlight might activate those stores

poderían ser activados pola luz solar para liberar o óxido desde a pel,

and release them from the skin,

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

onde os almacéns son dez veces máis grandes do que son na circulación.

Could the sun activate those stores into the circulation,

Podería o sol activar estes almacéns cara á circulación,

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

e aí, na circulación, facer cousas boas para o sistema cardiovascular?

Well, I'm an experimental dermatologist,

Ben, eu son dermatólogo experimental,

so what we did was we thought

e o que fixemos foi pensar que debiamos expoñer os coellos de indias á luz solar.

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

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

Así que collemos unha serie de voluntarios

and we exposed them to ultraviolet light.

e expuxémolos á luz ultravioleta.

So these are kind of sunlamps.

Son unha especie de lámpadas solares.

Now, what we were careful to do was,

Agora ben, fomos coidadosos co seguinte,

vitamin D is made by ultraviolet B rays

a vitamina D está feita de raios ultravioleta B

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

e queriamos separar o noso estudo do estudo da vitamina D

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

Así que usamos ultravioleta A, que non xera vitamina D.

When we put people under a lamp

Cando puxemos xente baixo a lámpada

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

durante o equivalente a 30 minutos de sol no verán en Edimburgo,

what we produced was, we produced a rise

o que producimos foi un crecemento na circulación de óxido nítrico.

in circulating nitric oxide.

So we put patients with these subjects under the UV,

Entón, ao poñer estes suxeitos baixo a luz ultravioleta,

and their NO levels do go up,

os seus niveis de NO medraron,

and their blood pressure goes down.

e a súa presión arterial diminuíu.

Not by much, as an individual level,

Non moito, a nivel individual,

but enough at a population level

pero abondo a nivel poboacional,

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

como para cambiar as taxas de enfermidades cardíacas en toda a poboación.

And when we shone UV at them,

Cando lles diriximos raios ultravioleta,

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

ou cando os quentabamos ao mesmo nivel que as propias lámpadas,

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

impedindo que os raios acadaran a pel, iso non sucedía.

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

Parece ser unha característica dos raios ultravioleta cando acadan a pel.

Now, we're still collecting data.

Agora aínda estamos recollendo datos.

A few good things here:

Algunhas cousas boas:

This appeared to be more marked in older people.

O efecto é máis pronunciado nas persoas maiores.

I'm not sure exactly how much.

Non sei canto exactamente.

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

Aquí, un dos suxeitos foi miña sogra,

and clearly I do not know her age.

de quen, obviamente, non sei a idade.

But certainly in people older than my wife,

Mais certamente en xente maior que a miña muller,

this appears to be a more marked effect.

este parece ser un efecto máis pronunciado.

And the other thing I should mention

Outra cousa que debo mencionar

was there was no change in vitamin D.

é que non houbo cambios na vitamina D.

This is separate from vitamin D.

Isto é independente da vitamina D. Así que a vitamina D é boa para ti:

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

it prevents calcium metabolism, important stuff.

frea o raquitismo, prevén o metabolismo do calcio, etc.

But this is a separate mechanism from vitamin D.

Mais isto é un mecanismo independente da vitamina D.

Now, one of the problems with looking at blood pressure

Un problema coa presión arterial é que o corpo fai todo o que precisa,

is your body does everything it can

para manter estable a presión arterial.

to keep your blood pressure at the same place.

If your leg is chopped off and you lose blood,

Se che cortan a perna e perdes sangue,

your body will clamp down, increase the heart rate,

o corpo toma medida:, incrementa o ritmo do corazón,

do everything it can to keep your blood pressure up.

fai todo o posible para manter a presión arterial.

That is an absolutely fundamental physiological principle.

É un principio fisiolóxico fundamental.

So what we've next done

O que fixemos despois

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

foi comezar a observar a dilatación dos vasos sanguíneos.

So we've measured -- this is again,

Medimos

--fíxense que sen cola e sen pelo, este é un estudante de medicina.

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

(Risos)

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

No brazo, pódese medir o fluxo sanguíneo,

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

calculando o que este incha cando o sangue o atravesa.

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

Demostramos que facendo unha irradiación simulada,

nesta liña máis grosa,

this is the thick line here --

this is shining UV on the arm so it warms up

radiando raios ultravioleta no brazo para quentalo,

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

manténdoo cuberto para que os raios non acaden a pel,

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

non hai cambio no fluxo sanguíneo, na dilatación dos vasos sanguíneos.

But the active irradiation,

Pola contra, a irradiación activa,

during the UV and for an hour after it,

durante a radiación ultravioleta e ata unha hora despois ,

there is dilation of the blood vessels.

provoca dilatación dos vasos sanguíneos.

This is the mechanism by which you lower blood pressure,

Este é o mecanismo polo que a presión arterial baixa,

by which you dilate the coronary arteries also,

polo que se dilatan as arterias coronarias,

to let the blood be supplied with the heart.

para que o corazón subministre sangue.

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

Aquí hai máis datos sobre os raios ultravioleta (UV), a luz solar,

has benefits on the blood flow and the cardiovascular system.

que ten beneficios no fluxo sanguíneo e no sistema cardiovascular.

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

Pensamos que conseguiramos un modelo,

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

diferentes cantidades de UV acadan a Terra en diferentes momentos do ano,

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

así pódense activar os almacéns de óxido nítrico,

the nitrates, nitrites, nitrosothiols in the skin --

os nitratos, nitritos, tionitritos na pel...

cleave to release NO.

descompostos para liberar NO.

Different wavelengths of light have different activities of doing that.

Diferentes lonxitudes de onda da luz teñen diferentes mecanismos para facelo.

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

Pódese ver a lonxitude de onda da luz que o fai.

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

Pódese observar que se vives no ecuador, o sol chega xusto sobre a cabeza,

it comes through a very thin bit of atmosphere.

atravesa unha capa fina de atmosfera.

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

A cantidade de luz é a mesma no inverno e no verán.

If you live up here, in summer

Se vives aquí no norte,

no verán o sol chega directamente,

the sun is coming fairly directly down,

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

pero no inverno atravesa unha gran cantidade de atmosfera,

and much of the ultraviolet is weeded out,

e moitos dos raios ultravioleta desfanse,

and the range of wavelengths that hit the Earth

e o rango das lonxitudes de onda que golpean a Terra

are different from summer to winter.

é diferente no verán e no inverno.

So what you can do is you can multiply those data

Entón podes multiplicar estes datos

by the NO that's released

polo NO que se libera

and you can calculate how much nitric oxide

e podes calcular canto

would be released from the skin into the circulation.

sería liberado pola pel na circulación.

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

Agora ben, se vives no ecuador,

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

nestas dúas liñas de aquí, as liñas vermella e violeta,

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

a cantidade de óxido nítrico que se libera é a área baixo a curva,

it's the area in this space here.

a área neste espazo de aquí.

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

Entón se estás no ecuador, en decembro ou en xuño,

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

libéranse grandes cantidades de NO da pel.

So Ventura is in southern California.

Na cidade de Ventura,

no sur de California, o verán pode ser tal e como é no ecuador.

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

It's great. Lots of NO is released.

É xenial. Libérase un montón de NO.

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

Ventura, na metade do inverno, hai aínda unha boa cantidade.

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

En Edimburgo, no verán, a área baixo a curva é bastante boa,

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

mais Edimburgo no inverno, a cantidade de NO que pode ser liberada

is next to nothing, tiny amounts.

é case nula, pequenas cantidades.

So what do we think?

Entón que pensamos?

We're still working at this story,

Seguimos traballando no estudo,

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

estamos desenvolvéndoo e expandíndoo.

We think it's very important.

Pensamos que é moi importante.

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

É probable que explique o gradiente de saúde entre o norte-sur do Reino Unido,

It's of relevance to us.

É relevante para nós.

We think that the skin --

Pensamos que a pel,

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

sabemos que a pel ten grandes almacéns de óxido nítrico baixo formas diversas.

of nitric oxide as these various other forms.

We suspect a lot of these come from diet,

Sospeitamos que isto procede da dieta,

green leafy vegetables, beetroot, lettuce

vexetais de folla verde, remolacha e leituga,

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

teñen moitos destes óxidos de nitróxeno que pensamos que van á pel.

We think they're then stored in the skin,

Pensamos que están almacenados na pel,

and we think the sunlight releases this

e pensamos que a luz solar os libera,

where it has generally beneficial effects.

onde teñen, polo xeral, efectos beneficiosos.

And this is ongoing work, but dermatologists --

Isto é un traballo en curso, pero os dermatólogos,

I mean, I'm a dermatologist.

é dicir, eu son un dermatólogo.

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

O meu traballo diario é dicirlle á xente:

"Tes cancro de pel por culpa da luz solar, non te poñas ao sol".

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

I actually think a far more important message

Penso que unha mensaxe realmente máis importante

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

é que a luz solar produce beneficios e riscos.

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

Si, a luz solar é o principal factor de risco modificable de cancro de pel,

but deaths from heart disease are a hundred times higher

pero hai centos de veces máis mortes por enfermidades do corazón

than deaths from skin cancer.

ca por cancro de pel.

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

Creo que necesitamos ser máis conscientes disto,

and we need to find the risk-benefit ratio.

e atopar a relación de risco-beneficio.

How much sunlight is safe,

Canta luz solar é segura,

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

e como podemos axustar mellor isto para a nosa saúde xeral?

So, thank you very much indeed.

Moitas grazas, de verdade.

(Applause)

(Aplausos)

[Recoñecementos]