地平线系列：肉食者的困境（2014）

五十多岁
This person is in their 50s.
你不得不承认 这是异常的肠道
You'd come across that and you're going, "that's abnormal."
如果不移除息肉
If the polyps aren't removed,
它们就可能癌变
they can turn cancerous.
为什么吃太多肉会长息肉呢
Why might a diet rich in meat lead to polyps?
就像医生一直常说的 这很复杂
Well...as doctors always say, it's complicated.
在肉里 尤其是在加工肉制品中
There are various factors in meat,
有许多相关的因素
particularly in processed meats,
有证据表明化学添加剂
chemical factors that have been shown
会增加患癌几率
to promote cancer
或刺♥激♥细胞加速生长
or to promote increased growth of cells.
根据我从其他专家那里听到的信息
In light of what I've heard from other experts,
我很好奇桑德森博士自己吃些什么
I'm curious to find out what Dr Sanderson himself eats.
你吃红肉吗
Do you eat red meat?
我的确是吃的
I most certainly do eat red meat.
我崇尚什么都吃点
I believe in being an omnivore.
但我觉得我没吃太多肉
I don't think I'm an excessive meat eater.
什么叫太多
OK, define excessive.
我觉得我自己
Well, I think I'll have... I'll have...
大概一周吃两次红肉吧
maybe have...you know, two bits of red meat each week.
如果我要改善我的膳食结构
If I was going to make one change to my diet,
我觉得我该少吃点加工肉制品
I think it's the... reducing those processed meats
这是一个很好的选择
that is the one good opportunity
这样你还是可以吃你的烤肉
and then you can keep your roast beef
还有牛排
and your...and your steak.
桑德森博士认为预防肠道癌症的最有效方式
Dr Sanderson thinks the most effective way to prevent bowel cancer
就是在55岁左右做一次结肠镜
is to have a colonoscopy in your mid-50s,
这样可以移除所有的息肉
so any polyps can be removed.
我们做的是
What we've done here is
用这个套圈
we have delivered this snare wire around the polyp
圈在息肉的连接处
and it's sitting on the stalk,
然后收紧钢丝
and we've tightened it
你可以看到通过给钢丝通电
and now you'll see we're going to apply a current to this stalk,
会产生一些烟雾和灼伤
and then you'll see some smoke and burning generated.
这都是在内窥镜末端完成的吗
That's all on the end of the endoscope?
对 我们只要收紧它然后进行切除
Yes, so we're just tightening it and then...there it goes,
这样息肉就没了
and that's it, polyp gone.
-噗地就不见了 -我们叫它前息肉
- It's gone, "pop". - We call that an ex-polyp.
那火腿培根等加工肉制品中的
So, what is it that makes processed meat like ham and bacon
什么物质是可能致癌的呢
potentially carcinogenic?
是什么会促进癌变息肉的增生呢
What's in it that could promote the growth of cancerous polyps?
我回到雷丁大学
I'm back at Reading University's
食品营养科学系寻找答案
Food and Nutritional Sciences Department to find out.
有什么比亲自动手做一次更有用的呢
And what better way than to actually make some?
丹尼·康曼博士是
Dr Danny Commane is a specialist
胃肠道健康和结直肠癌方面的专家
in gut health and colorectal cancer.
他找来了把猪肉
He's gathered together everything we need
制成培根的所需的所有材料
to turn pork into bacon,
这是我和全国人♥民♥最爱的加工肉制品
the nation's, and my, favourite processed meat.
你好
Hi there.
你好 迈克尔 我们来腌制一些培根
Hi, Michael, we're going to cure some bacon,
-手套给你 -我从来没做过培根
- I'll give you the gloves. - I've never done this before.
这是海盐 需要加十二茶匙
OK, so, we've got some sea salt and we need 12 teaspoons of it.
十二勺 这么多
12?! Blimey! OK.
对
Yeah.
只有当你亲自来做的时候
It's only when you make it yourself
你才会意识到里面有多少盐
you realise how much salt there is in it.
好 就是这样
Yeah, that's right.
糖要加多少
Sugar, how much?
要加五茶匙
So, five teaspoons of sugar,
然后我们需要加腌渍用盐
and we've just got curing salt
里面含有亚硝酸钠
which contains our sodium nitrite.
好像不鼓励加太多 上面写着
OK, it's not encouraging, it says,
"适量使用 否则具有毒性"
"Toxic if not used correctly",
这个要放多少 我要小心点放
and how much of this stuff? I'll be careful with this.
一勺就好
Just one teaspoon.
然后要把它们混匀吧
And then, presumably, you just mix it up, do you?
没错
That's right, yeah.
然后我们要把它揉进肉里
And then we're going to massage it into our...into our meat,
充分吸收
mix it well in,
尽量让它渗入到每个缝隙中
try and get into all the cracks and crannies in the meat.
涂好调料后
Once the cure is applied,
这块肉会被放进冰箱
the meat will need to be refrigerated
大概腌制七天
to cure for about seven days.
你注意到的第一件事
The first thing you notice is just
就是这个过程中用了多少盐
how much salt is involved in the process.
太多盐当然对人的身体不好
The salt is obviously not great for us.
盐跟高血压紧密相关
It's related to hypertension
高血压是引发心血管疾病的主要原因
which is a leading cause of cardiovascular disease.
而且不仅盐会导致问题
But it's not just the salt that can cause problems,
还有腌制过程中
there's also the sodium nitrite I added
我们常常需要加的亚硝酸钠
which is often used in the curing process.
亚硝酸钠究竟是什么 有什么用
So, what it is about the sodium nitrite, what does it do?
亚硝酸盐非常适用于肉类
The nitrite, it's very good for the meat,
它能杀死肉里面的细菌
it kills the bacteria in the meat,
防止肉毒杆菌中毒
it stops us getting botulism,
然而据说在胃里
however in the stomach environment
亚硝酸盐可能会和
it's believed that some of that nitrite reacts with amino acids -
构成蛋白质的氨基酸发生反应
the building blocks of protein
产生亚硝胺
to form what we call nitrosamines,
亚硝胺性质非常活跃
and we believe that these are quite chemically reactive.
当它们进入消化道时
And when they make their way down into the gastro-intestinal tract,
就能与细胞和组织中的DNA产生相互作用
they can start interacting with DNA in cells and tissues
我们认为这是癌症的开端
and that is what we believe initiates the cancer process.
有什么证据证明亚硝酸盐
OK, and how strong is the evidence of a direct link
与癌症之间的联♥系♥吗
between nitrites and cancer?
这是一个复杂的设想
It's a very complicated picture.
我们认为它可能导致癌症发生
We believe that it may contribute
但也想弄清楚具体原因
but we want to understand why,
这只是可能机制之一
and this is one potential mechanism.
所以亚硝酸盐只是有嫌疑
So nitrites are still only a suspect,
我们还没能将它与肠癌发生
we have yet to establish a direct link between them
直接联♥系♥起来
and colorectal cancer.
而亚硝酸盐只是腌制过程中
And nitrites are not the only part of the curing process
受研究者关注的一部分
that researchers wonder about.
我们要点火啦
There we go, we have liftoff!
肉类的熏制一般是在大型冷藏库中进行
When meat is smoked, it's often done in massive cold stores,
而我们的规模要小得多
we're doing it on a much more intimate scale.
给肉类增加风味的方法之一
One of the things that we do to flavour meat
就是熏制
is we smoke it,
熏制的过程会产生一种
and the same chemicals that we generate
与我们吸烟的时候
when we smoke cigarettes,
相同的化学物质
things called polyaromatic hydrocarbons,
名叫多环芳烃
are generated in the smoking process.
这些多环芳烃
These chemicals, known as PAHs,
会残留在肉中
stick to the meat
随着食用会被身体吸收
and when we eat it, they can be absorbed by the body.
它们也会在我们的消化道内产生
They can react in a very similar way to the nitrosamines with DNA
类似于亚硝胺和DNA的反应
through our gastrointestinal tract
这可能是另外一种潜在机制
and might be another potential mechanism
因此红肉和加工肉制品
whereby red and processed meats
会增加人类患胃肠道癌症的机率
increase our risk of gastrointestinal cancers.
在探索加工肉制品与癌症的关联时
Like nitrites, PAHs are still only potential suspects
和亚硝酸盐一样
when it comes to finding a link
多环芳烃仅是怀疑对象
between processed meat and cancer.
尽管如此 我仍然意识到
Still, I'm starting to see
加工肉制品臭名昭著的原因了
why processed meat has such a bad reputation.
可它们的名声究竟有多不好呢
But just how bad is bad?
来自哈佛大学和
The Harvard and
欧洲癌症与营养前瞻性调查委的研究均表明
EPIC studies both suggest