牛奶是白色毒药，还是健康饮品？：英语精读讲义

Over the last decade, 短語搭配

在过去的十年里，

milk has become a bit controversial. 語氣意圖

牛奶变得有些争议。

Some people say it's a necessary and nutritious food

有些人说它是必要且营养丰富的食物，

vital for healthy bones,

对骨骼健康至关重要，

but others say it can cause cancer

但其他人说它会致癌，

and lead to an early death. 短語搭配

并导致早逝。

So,

那么，

who's right?

谁是对的？

And why are we drinking it anyway?

还有，我们为什么要喝牛奶呢？

Milk is the basis of every mammal's diet after birth

牛奶是所有哺乳动物出生后的基础食物，

when our digestive systems are immature and small.

因为那时我们的消化系统还不成熟且很小。

Basically,

基本上，

it's power food to kickstart our bodies 習語

它是一种能够启动我们身体的能量食物，

and help us grow.

帮助我们成长。

Milk is rich in fat,

牛奶富含脂肪、

vitamins,

维生素、

minerals,

矿物质，

and milk sugar,

以及奶糖，

lactose.

即乳糖。

On top of that, 表達脈絡

除此之外，

for a while after birth,

在出生后的一段时间里，

it also contains antibodies and proteins

它还含有抗体和蛋白质，

that protect us from infections

保护我们免受感染，

and regulate our immune system.

并调节我们的免疫系统。

But it's a lot of effort for mothers to produce. 語法

但这对母亲来说是很大的消耗。

Eventually,

最终，

humans stop drinking mother's milk

人类会停止喝母乳，

and transition to the diet of their parents. 短語搭配

并过渡到他们父母的饮食。

This is how it's been for thousands of years.

数千年来一直如此。

Until about 11,000 years ago,

直到大约1.1万年前，

when our ancestors settled down in the first agricultural communities. 短語動詞

当我们的祖先在最早的农业社区定居下来。

Soon,

很快，

they domesticated the first dairy animals,

他们驯化了第一批产奶动物，

goats,

山羊、

sheep,

绵羊、

and cattle.

和牛。

They found that dairy animals are able to eat useless and abundant stuff

他们发现产奶动物能吃掉无用且多余的东西，

and turn it into nutritious and tasty food. 短語動詞

并将其转化为营养美味的食物。

This made a huge difference in terms of survival, 短語搭配

这在生存方面带来了巨大的改变，

especially in hard times.

尤其是在艰难时期。

So,

因此，

groups that had milk available

拥有牛奶的群体

had an evolutionary advantage. 短語搭配

就有了进化上的优势。

And through natural selection,

而通过自然选择，

it changed the genes of communities

它改变了社区的基因，

who consumed a lot of it.

这些社区大量摄入了牛奶。

This adaptation has to do with a specialized enzyme, 短語搭配

这种适应性与一种特殊的酶有关，

lactase.

即乳糖酶。

Babies have a lot of it in their system,

婴儿体内有大量的乳糖酶，

so they can break down the milk sugar lactose 短語動詞

所以他们能分解奶糖（即乳糖）

and digest milk easily.

并轻松消化牛奶。

But the older we grow, 語法

但随着我们长大，

the fewer lactase enzymes our body produces.

身体产生的乳糖酶越来越少。

Worldwide,

在世界范围内，

about 65% of the population

大约65%的人口

do not have the enzyme after infancy,

在婴儿期后就不再有这种酶，

which means they are not able to digest more than about 150 ml each day.

这意味着他们每天最多只能消化约150毫升的牛奶。

This lactose intolerance is not spread evenly around the world, 短語搭配

然而，这种乳糖不耐受在世界范围内的分布并不均匀，

though.

不过。

In some East Asian communities,

例如，在一些东亚社区，

for example,

例如，

it's up to 90%.

这个比例高达90%。

In Northern Europe and North America,

在北欧和北美，

the rates are the lowest overall.

总体比例是最低的。

There are probably a few reasons for this uneven distribution.

这种不均匀的分布可能有几个原因。

The trait was first introduced by random mutation,

这种特征最初是由随机突变引入的，

which happened independently of each other in a few populations. 短語搭配

这些突变在几个种群中各自独立发生。

The fact that farming replaced hunting and gathering more and more

农业越来越多地取代狩猎和采集这一事实，

created natural selection pressure.

带来了自然选择的压力。

People who were able to digest lactose

能够消化乳糖的人

had more foods at hand, 習語

手头有更多的食物，

which was an advantage.

这是一个优势。

The migration of dairy farmers to the north

奶农向北方的迁徙

then spread it further,

随后进一步传播了这种特征，

which probably pushed back populations 短語動詞

这可能排挤了那里

there that didn't have the trait.

没有这种特征的种群。

Okay,

好吧，

but if milk has been a valuable part of our diet for thousands of years,

但如果数千年来牛奶一直是我们饮食中重要的一部分，

why is it so controversial?

为什么它会如此具有争议呢？

There are a number of claims regarding the negative and positive health effects of milk. 短語搭配

关于牛奶对健康的负面和正面影响，有许多说法。

The negative ones cover a wide variety.

负面影响种类繁多。

From brittle bones to cancer and cardiovascular diseases

从骨质脆弱到癌症和心血管疾病，

to intolerance and allergies.

再到不耐受和过敏。

So,

那么，

how do they hold up? 短語動詞

这些说法站得住脚吗？

Some older studies found a connection between milk and a high risk of breast,

一些早期的研究发现牛奶与乳腺癌高风险之间存在联系，

colon,

结肠癌，

and prostate cancer.

和前列腺癌。

But meta-analyses found no impact on your cancer risk. 用詞

但荟萃分析发现对你的患癌风险没有影响。

On the contrary, 表達脈絡

相反，

the calcium in milk might even have a protective effect against colon cancer.

牛奶中的钙可能甚至对结肠癌有保护作用。

Although this could be calcium in general,

尽管这可能是一般意义上的钙的作用，

it's not clear milk plays a role in this effect. 短語搭配

目前尚不清楚牛奶是否在这种效应中发挥了作用。

Only studies on prostate cancer showed an increased risk for people who consumed more than 1 and 1/4 L of milk a day.

只有关于前列腺癌的研究显示，每天饮用超过1.25升牛奶的人风险会增加。

But again,

但同样，

the association is inconsistent 用詞

这种关联是不一致的，

and other studies don't find any effects.

其他研究也没有发现任何影响。

We discuss these studies in more detail in our sources document.

我们在我们的来源文档中更详细地讨论了这些研究。

All in all, 表達脈絡

总而言之，

the research seems to show that if you drink between 100 to 250 ml of milk per day,

研究似乎表明，如果你每天喝100到250毫升的牛奶，

cancer is not a concern.

癌症不是一个问题。

Similarly,

同样，

meta-analyses could not find any impact from milk or dairy products on your risk of heart disease,

荟萃分析未能发现牛奶或乳制品对你的心脏病风险有任何影响，

stroke,

中风，

or your total mortality.

或是你的总死亡率。

Some studies even suggested that high blood pressure might be rarer in people who eat a lot of dairy,

一些研究甚至表明，吃大量乳制品的人可能更少患高血压，

although the evidence is not strong enough to claim this with confidence. 短語搭配

尽管证据还不足以让我们有信心地断言这一点。

The case gets more complicated, 表達脈絡

不过，情况变得更加复杂，

though,

然而，

when we look at bones.

当我们关注骨骼时。

A number of studies found neither positive nor negative effects for adults.

许多研究发现对成年人既没有正面影响也没有负面影响。

What most people worry most about,

不过，大多数人最担心的，

though,

还是，

are harmful amounts of pesticides,

是农药、

antibiotics,

抗生素、

or hormones.

或激素的有害含量。

There are hormones in milk,

牛奶中确实含有激素，

but only in very low concentrations.

但浓度非常低。

For example,

例如，

to get the same amount of hormones as from the pill,

要获得与避孕药相同量的激素，

you'd need to drink about 5,000 L of milk,

你需要喝大约5000升牛奶，

and even if you did, 語法

即使你真的喝了，

most hormones would be destroyed by your digestive system

大多数激素也会被你的消化系统破坏，

before they could affect you,

在它们能影响你之前，

which is the reason why so much medication is coated, 語法

这也就是为什么很多药物都有一层包衣，

to protect it from our digestion.

以保护它们不受我们消化的影响。

For pesticides and antibiotics,

至于农药和抗生素，

there are regulations in most parts of the world

世界上大部分地区都有相关规定，

that only allow completely harmless amounts.

只允许完全无害的含量存在。

Milk that surpasses these thresholds is not allowed to go on the shelf. 講解

超过这些阈值的牛奶是不允许上架的。

So,

所以，

there's nothing in particular to worry about. 語氣意圖

没有什么特别需要担心的。

Besides allergies and those suffering from lactose intolerances,

除了过敏和乳糖不耐受患者，

the best known negative effects of milk are probably acne and general discomfort after drinking milk or eating dairy products.

牛奶最著名的负面影响可能是喝牛奶或吃乳制品后的痤疮和全身不适。

And here,

而在这方面，

the effects are very real.

影响是非常真实的。

For example,

例如，

skimmed milk has been found to statistically increase the rate of acne by 24%. 語法

统计发现脱脂牛奶使痤疮发生率增加了24%。

Allergies against milk products are especially prevalent among children,

对乳制品过敏在儿童中尤为普遍，

with one in 18 kids in Germany suffering from them. 語法

在德国每18个孩子中就有一个患有这种过敏。

In general,

总的来说，

these allergies tend to get better or disappear as they grow older, 語法

这些过敏往往会随着年龄的增长而好转或消失，

though.

不过。

Okay,

好的，

is milk healthy,

那么牛奶健康吗，

then?

到底？

Milk,

牛奶，

no matter if it comes from mothers, 語法

无论它是来自母亲、

cows,

奶牛、

sheep,

绵羊、

goats,

山羊、

or camels,

还是骆驼，

is a nutrient-dense food. 用詞

都是一种营养密集的食物。

It contains all necessary macronutrients

它包含了所有必需的常量营养素，

and many micronutrients.

以及许多微量营养素。

Especially in regions where people struggle to get enough calories,

尤其是在人们难以获得足够热量的地区，

milk can contribute to a healthy life and lower child mortality.

牛奶有助于健康生活并降低儿童死亡率。

For those living in the developed world,

对于生活在发达国家的人来说，

in general,

总的来说，

milk is not harmful if you are not allergic or intolerant to it.

如果你对牛奶不过敏或不耐受，它就是无害的。

Especially for children,

特别是对于儿童来说，

it's a good way to get large amounts of calcium,

它是获取大量钙的好方法，

and for vegetarians,

而对于素食者，

it's a good source of vitamin B12 and B vitamins in general.

它是维生素B12和一般B族维生素的良好来源。

This does not mean there are not other alternatives with the same effect. 語法

这并不意味着没有其他具有相同效果的替代品。

You do not need to drink milk to be healthy.

你不需要为了健康而喝牛奶。

Milk is also definitely not a substitute for water. 短語搭配

牛奶也绝对不能代替水。

Milk is power food,

牛奶是能量食物，

and the additional calories from drinking a lot of it on a regular basis 短語搭配

经常大量饮用它带来的额外热量，

can contribute to being overweight.

可能会导致超重。

Especially flavored milk or chocolate milk

特别是风味牛奶或巧克力奶，

is more comparable to beverages like lemonade 語法

相比健康零食，它更像柠檬水之类的饮料，

than a healthy snack.

而不是健康零食。

And there's another thing to consider. 表達脈絡

还有另一件事需要考虑。

Milk production has a significant impact on the global climate. 短語搭配

牛奶生产对全球气候有着重大影响。

About 33% of cropland is used to feed grazing animals,

大约33%的农田被用来喂养放牧动物，

including dairy cattle.

包括奶牛。

Even though the carbon footprint of dairy products has declined since 1990, 語法

尽管自1990年以来乳制品的碳足迹有所下降，

dairy production is still responsible for 3% of all greenhouse gas emissions,

乳制品生产仍占所有温室气体排放的3%，

even more than all airplanes combined.

甚至比所有飞机的总和还要多。

Milk is a huge industry,

牛奶是一个庞大的产业，

and sadly,

而可悲的是，

most of its production in factory farms causes incredible suffering.

在工厂化农场的大部分生产造成了难以置信的痛苦。

Cows are impregnated over and over, 習語

奶牛一次又一次地受孕，

separated from their young shortly after birth,

出生后不久就与幼崽分离，

and slaughtered once their tortured bodies are not productive anymore.

一旦受尽折磨的身体不再具有生产力就会被屠宰。

We can't ignore that much of the milk we consume stems from an industry that is basically torture 短語搭配

我们不能忽视，我们消费的许多牛奶源自一个本质上是折磨的行业，

and contributes to climate change.

并且促成了气候变化。

What about plant-based milk? 表達脈絡

那植物奶呢？

In terms of protein levels and nutritional value,

就蛋白质水平和营养价值而言，

only soy milk can compare to cow milk. 短語搭配

只有豆奶可以与牛奶媲美。

The others need to be artificially enriched 用詞

其他的需要人为强化，

to reach similar levels of vitamins and calcium.

以达到相似的维生素和钙水平。

So,

所以，

they can be an alternative to milk.

它们可以作为牛奶的替代品。

And another option might be available soon. 語法

而另一种选择可能很快就会出现。

Several startups have created non-animal milk that is nutritionally identical to dairy milk, 短語搭配

几家初创公司已经创造出营养成分与牛奶相同的非动物奶，

for example,

例如，

through fermentation by gene-modified bacteria. 用詞

通过转基因细菌发酵。

This lab-grown milk can even be turned into cheese, 短語動詞

这种实验室培育的牛奶甚至可以制成奶酪，

something that plant-based alternatives struggle with 短語搭配

这是植物基替代品难以做到的，

because they lack casein and whey protein,

因为它们缺乏酪蛋白和乳清蛋白，

the key ingredients that give dairy its taste and structure.

而这些是赋予乳制品口味和结构的关键成分。

The environmental impact is a different story, 習語

然而，对环境的影响则是另一回事，

though.

不过。

Many milk alternatives use significantly less energy,

许多牛奶替代品使用的能源显著更少、

land,

占用的土地，

and less water to produce,

和生产用水也更少，

so they have a much lower environmental impact than animal milk. 語法

所以它们对环境的负面影响比动物奶低得多。

If you want to have the lowest possible negative impact on the planet,

如果你想尽可能降低对地球的负面影响，

the best choice is whatever milk alternative is regional. 語法

最好的选择是任何在当地生产的牛奶替代品。

As with almost any topic, 表達脈絡

几乎所有话题都是如此，

milk is complicated.

牛奶是一个复杂的问题。

It's not harmful for the majority of the population,

它对大多数人来说并无害处，

and it's crucial for many people around the world.

对世界上许多人来说更是至关重要。

It's good,

它是优质、

nutritious food,

营养丰富的食物，

but also harmful to the planet

但同时也对地球有害，

and causes a lot of suffering.

并造成了许多痛苦。

We need to decide as a society

作为一个社会，我们需要决定，

how we want to deal with these facts. 短語動詞

我们想如何应对这些事实。