Beautiful and fascinating milk. As a neonatologist, a baby doctor, for decades I focused my research on nutrition in babies. Milk was thus always at the forefront of my attention. And there was always something interesting to discover or investigate about it.
美妙绝伦的母乳. 作为一个新生儿学专家，一个儿科医生，我对婴儿营养学有着长达数十年的研究。首当其冲吸引我的注意力的是母乳，于是我逐渐发现了母乳背后所蕴含的奇妙知识。

Just this year, in 2022, the announcement of a USA national shortage of milk formula for babies was truly bizarre and unimaginable! Who would have thought that that could happen in a so-called advanced country like ours? A reminder to us all that milk is truly an essential food for babies and that it cannot be easily replaced.
就在今年2022年，美国宣布了一个让人惊讶和难以想象的消息，那就是婴儿配方奶粉短缺。谁能想象到在美国这样一个发达国家里还能发生奶粉短缺的事情，这真是提醒了我们所有人，母乳是一个多么重要又难以被轻易取代的婴儿食物。

What’s smarter than the two brain lobes of the smartest scientist? A poetic scientist once proclaimed that the two lobes that normally produce milk are far superior to the brain lobes of the smartest scientist. That’s close to the truth, since milk production is one of the most perplexing mysteries in biology. Brilliantly producing greatly needed essential nutrients, chemicals, good microbes, antibodies, enzymes, immune factors and a host of chemical signals. Which allow babies to grow perfectly! What else can produce such a perfect concoction?

什么比最聪明的科学家的两个大脑脑叶还智能？曾经有一名科学家充满诗意地这样描述：女性的乳房作为负责产奶的工厂
比最聪明的科学家的脑子还要先进。其实这是很接近事实的，因为乳汁的产生就是生物学最复杂的奥秘之一。乳汁能完美地提供新生宝宝的生长发育所需要的基础营养物质，化学物质，好微生物，抗体，酶，免疫因子，以及大量的化学信号。所以要人工调制出乳汁是何其难。

“Cow’s milk is for calves!” Thus declared Dr. Frank Oski, world-renowned pediatrician. He was making a significant point about keeping cow’s milk for cows, and human milk for humans. Plus, by implication, goat’s milk for little goats, pig’s milk for piglets. Because there are huge differences among the various mammalian milks, and each milk is specific to each species!

“牛奶应该属于小牛.” 世界知名的儿科医生——弗兰克 奥斯奇(Frank Oski) 医生用这样一句话有力地指出这样的事实：牛奶应该专属于小牛，人类的母乳才属于人类。不仅如此，羊奶应该专属于小羊，猪奶应该专属于小猪。这不难理解，因为每一种哺乳动物都会产生专门针对自己物种的母乳。

Can cow’s milk really cause problems for my baby? Yes, very definitely. There have been literally thousands of papers written about the differences between cow’s milk and human milk, and how cow’s milk is not suitable for human babies. The good thing, of course, is that modern formula companies have made numerous attempts to make their cow’s milk-based formulas more compatible with the needs of human babies. They have done a great job but, frankly, nothing like human milk has ever been produced! Or to put it another way, no formula has ever been made that is exactly like human milk, no matter how much effort has been made.
牛奶真的能对人类宝宝产生危害吗？ 是的，这个答案非常确定。数以千计的学术论文已经研究了牛奶和人奶之间的区别，以及牛奶为何不适合人类婴儿。好消息是，现代配方奶粉公司已经致力于如何把基于牛奶的配方奶粉改造得更适合人类婴儿。他们确实做得很好，但坦率地说，和人类母乳完全一样的婴儿配方奶粉还未诞生。换句话说，无论付出多少努力，配方奶粉并不能做到和人类母乳完全一样。

And for my specialized area of calcium research, it was once quite a disaster to feed cow’s milk to human babies, because cow’s milk rapidly affected the babies’ calcium balance.
我的专业研究领域——对钙的研究显示，给婴儿喝牛奶会迅速影响婴儿的钙平衡，从而带来灾难级的影响。

Isn’t it bizarre to think cow’s milk can cause babies to have seizures? Maybe it sounds bizarre, but it’s true. It happened when cow’s milk causes significant drops in the baby’s blood calcium levels, which then resulted in clinical seizures. Many babies suffered with seizures before this was understood.
如果有人说牛奶会导致婴儿抽搐，你会觉得匪夷所思吗？ 虽然听起来可能令人觉得难以相信，但这确实是事实。牛奶会导致婴儿的血钙水平显著降低，从而导致婴儿临床性抽搐。很多婴儿发生抽搐，后来才知道是这样的原因导致的。

It was discovered that the high phosphate content in cow’s milk was what caused the calcium drop. So formula companies which used cow’s milk (the majority of formulas) in their infant formulas changed the phosphate content, and the problem of low blood calcium was then markedly reduced.
因为研究发现牛奶中含有过高的磷导致血钙下降。那些需要使用牛奶作为配方基底的配方奶粉公司于是改变牛奶中的磷含量，从而显著减少了婴儿血钙过低的发生率。

However, just before my early retirement from academic research, we actually detected that there was still a significant stress on the calcium control system in infants receiving standard formulas, which still might be potentially problematic for the long term. From my viewpoint, this area still needs to be studied further.
然而，就在我从学术工作提前退休之前， 我们检测到配方奶
喂养仍然给新儿的血钙控制系统带来显著压力。长期来看，配方奶
喂养仍可能导致潜在问题。所以我个人还是认为，这一问题还有待进一步研究。

What’s the strange relationship between milk and lactose? Indeed, lactose is one of those really strange sugars that we find naturally only in milk! You can’t find lactose in sugar cane, sugar beets, grapes or any other normal source of sugar! Nor essentially anywhere else in normal biology.

母乳和乳糖是什么样的奇怪关系? 乳糖确实是我们只能在母乳里发现的最奇特的一种糖！ 在任何其他正常的糖来源比如甘蔗，甜菜，葡萄中，都不含乳糖。甚至正常生物体的任何其他地方都找不到乳糖。

Furthermore, it’s also essentially the one and only carbohydrate or sugar in natural milk; there’s basically no other sugar at all in milk. These strange circumstances literally mean lactose must be doing something quite unique, but only in milk! After all, the word lactose is formed from Latin lac (“milk”) +‎ -ose (“sugar”).
除此之外，乳糖是自然界母乳中唯一的碳水化合物或糖。乳糖如此特殊，这说明它一定在母乳中发挥着某种特别的作用。别忘了，乳糖的英文名字lactose 就来自拉丁文的“奶or乳
lact”和“糖 ose”的组合。

Have you been labeled as “lactase deficient”? Lactase is the enzyme which helps you digest lactose. In theory, if you’re labeled as “lactase deficient”, you can’t drink too much milk or eat a lot of dairy products. You probably know many people who have this label and take Lactaid (lactase) to “help digest the lactose” when they drink milk or eat dairy products like cheese.
你被诊断为“乳糖酶缺乏症”过吗？乳糖酶是一种帮助消化乳糖的消化酶。理论上，如果你被诊断为“乳糖缺乏症“，那么你不能喝太多牛奶或吃太多乳制品。你可能从身边一些患有乳糖酶缺乏症的人身上知道，如果他们喝牛奶和吃类似芝士的乳制品时，那需要服用乳糖酶药片来帮助乳糖消化，

You’re more normal than you think! Low lactase, however, is actually normal! Surprise! In reality, all mammals (animals that produce milk) always have very high levels of lactase in their gut during their baby period when milk intake is essential. High lactase therefore is present only when high milk and lactose intake is needed. Presumably a perfect fit in time and function.
你比你想象的更正常！实际上，低消化酶是正常的。自然界中，所有能产奶的哺乳动物在它们需要吸收母乳的婴儿时期，肠道中的乳糖酶水平通常很高。这种高乳糖酶水平正好可以用来帮助婴儿消化母乳和乳糖。我们推断这大概是时间和功能上的一个完美配合。

The next phase in a baby’s life is weaning, meaning weaning the baby off breast milk. At weaning, surprise, in all mammals there is a dramatic drop in lactase, coincident with no longer needing milk or lactose, which again makes perfect sense.
婴儿的下一个生命阶段是断奶期，让人惊讶的是，所有的哺乳动物的乳糖酶都会在断奶期急剧降低，这又是另一个完美的配合
，因为断奶期后婴儿不再需要母乳或乳糖。

Thus, in biologic reality, lactase is really only needed when milk is needed. So all adults really should have low lactase, as part of normal development!
所以，在现实中的生物学里，只有在人体需要吸收母乳的时期才会需要乳糖酶。成年人的乳糖酶水平比较低是一个完全正常的生长发育结果。

But wait! Don’t we all need to drink cow’s milk!? Most westernized people think that everyone should drink milk. No, not really, and vast populations of the world do not drink milk or drink only a small amount of it. A high intake of milk after infancy often began when domesticated cows were extensively raised in Europe; the (usually) commercialized habit then spread around the world. Of course, there are also people who drink milk from camels, horses, goats, and yaks, but that’s another story.
但是等等，难道我们都不需要喝牛奶！? 大部分的西方人认为每个人都需要喝牛奶。但事实并不是这样，世界上的大部分不喝或者只喝少量牛奶。欧洲本土饲养奶牛数量剧增后，人们才会在婴儿期之后仍然大量摄入牛奶，这样的商业习惯也因此传播到世界各地。当然，也有人习惯喝骆驼奶，马奶，山羊奶和牦牛奶。这就是另一个故事了。

Did you realize no other mammal normally drinks milk after weaning? Except for domesticated kittens, who obviously learned it from their bosses. If you didn’t know that before, now you do.
你知道除了猫咪会从自己的主人习得喝奶习惯外，其他的哺乳动物在正常情况下断奶后不再喝奶吗？如果你以前不知道，那现在你知道了。

So who’s normal? Usually in population research, we say that the majority wins, so that if the majority of adults do not really have much lactase, we would have to conclude they are normal. So quit labeling yourself as lactase deficient! You’re not.
所以谁是正常的？人口学研究中通常以多数取胜，因此如果大多数成年人并没有多少乳糖酶，那低乳糖就是一个正常现象。所以，你是完全正常的，请给自己撕掉所谓的乳糖酶缺乏症这样的标签吧。

In history, all human babies normally have relied initially on only human milk to survive. That is self-evident. So it should be no surprise that in nutrition research, everyone considers human milk as the gold standard, when trying to determine any specific nutrition needed for babies. This still might beg the question of who set up this gold standard, and why it is really the standard.
在历史上，所有的人类婴儿通常情况下起初都是靠喝母乳来生存。这显然是不言而喻的，因此营养学上将母乳公认为婴儿营养的黄金标准。这让我们不禁想问，这个黄金标准是谁建立的，为何它成为标准？

And I think the answer is simply that It’s indeed a self-evident standard: in babies, what else would we really base the key nutrition standard on? Historically, without this gold-standard nutrition, the baby dies; that’s pretty dramatic, I would think. All over the world, over all generations. There can be other standards, but they’re just not gold.
我想答案很简单而且同样是不言而喻的：除了婴儿本身，我们又能在哪里检验这一关键营养标准呢？从历史的角度来说，如果没有这达到黄金标准的营养，婴儿就不会存活。我稍微想象一下这种情形都会觉得可怕。全世界范围内的各个世代可能都会存在别的标准，但它们都达不到黄金标准。

我个人对母乳和配方奶的关注。在几十年的医学学术生涯中，我组建了一支由营养学的临床医生和科学家组成的科研团队，他们非常活跃，致力于钙和配方奶研究。因为早产儿的营养需求与足月婴儿完全不同，于是，我们感兴趣的一个领域正是系统性地优化营养和婴儿配方奶来喂养早产儿。正如我们的许多书籍 (1) 中所总结的那样，研究各种形式的奶是我一段非常有趣而迷人的人生时光。

Lazy conclusion. During my research years, I heard a brilliant, practically inspirational, lecture on the beauty of human milk. It included a “Star Wars presentation” of all the innumerable immune or defense factors that are present, and how the entire natural milk production system includes a complex system of protection (hence “Star Wars”) for the baby. At the end of the talk, the speaker poetically concluded how wonderful it was that evolution caused this to happen.

偷懒的术语。在我的科研岁月中，我曾听过一个关于母乳之美的极具启发意义的精彩讲座。讲座展示了如同“星球大战”般的无数免疫或防御因子参与的完整天然产奶系统所为婴儿提供的复杂保护体系（难怪比喻成“星球大战“）。在讲座结束时，演讲者充满诗意地赞叹：进化导致这一切发生是多么地奇妙。

Afterwards, I went to talk to this lecturer and I asked him what his conclusion meant: did he really believe that breast milk “evolved”? He admitted that wasn’t what he meant; what he meant was, it was like a God mystery! I suggested, and he agreed, that maybe he shouldn’t use such lazy terms as “evolution” if he didn’t really believe it!
后来我去找这位演讲者，继续询问他的结论是什么意思：他真的相信母乳是能“进化的”吗？他说这不是他的本意。他的意思是这就像上帝的一个奥秘！于是我建议他（他也同意）如果不真的相信“进化”的话，就不要偷懒地使用“进化”这个术语。

There’s no way that breast milk became better and better over millions of years. In fact, everyone should agree that there’s no logical way that human milk could actually evolve step-by-step from some “lower human” or other creature. All babies would have died waiting for it to happen!!
母乳不可能在数百万年里越变越好！每个人都应该知道，从逻辑上母乳不可能是能从所谓的“低端人类”或者其他种类生物一步一步进化至今的，不然，所有的婴儿应该都在等待中死亡了。

There’s just no way that human milk can produce thousands of different chemicals or nutrients step-by-step through millions and millions of years. It’s clearly one of those all-or-none things in life. You either have the whole perfect human milk, or the baby will die. You can’t have any partially complete milk! Nor partial death scenarios either.
母乳不可能在数百万年的时间里一步一步地产生数以千计的不同化学物质或营养物质。这显然属于那类“零或一”或“非黑即白“的生命问题，是不可能有一个中间的半成品状态的。换句话说，你要么能得到完美的母乳，要么婴儿就会因得不到所需营养而死亡。你不可能得到半成品母乳，同样地也不可能见识到部分死亡。

It’s as impossible as the theorized/fantasized pathetic efforts of a rat pup sucking vigorously on its mother’s sweat glands, generation after generation, in order to hope to produce a mammary gland! It’s really boils down simply to “Give me milk or give me death!” There has to be a better way.
这就像一代又一代的老鼠幼崽如果通过用力吸吮母亲的汗腺来希望产生乳腺， 这是一种从理论上或想象中都极其可悲的努力，也是注定是不可能实现的。这情形确实可以简单归为“给我奶喝或让我死“。一定会有更好的办法！

A beautiful design. All natural milks are complexly designed and totally functional. They are really a perfect design. And human milk is made specially and specifically for human babies, which is perfectly logical. Precise, simple and correct. And billions of babies appreciate that. Including you, once upon a time.
美丽的设计。自然界中的母乳都是一个完美的设计，经过复杂设计且功能齐全。而母乳是专门为人类婴儿而创造的，这完全合乎逻辑，准确、简单、正确。曾几何时，数十亿婴儿都享受着母乳。这其中也包括你。

Reference:

• Tsang, RC; Uauy, R; Koletzko, B; Zlotkin, S; (2005) Nutrition of the Preterm Infant: Scientific Basis and Practical Guidelines.Digital Educational Publishing.Inc

参考文献:

• 婴儿营养原理与实践
  Nutrition During Infancy: Principles and Practice 第2版, 2009, 原著 Reginald C. Tsang, Stanley H. Zlotkin, James W. Hansen, Buford L.Nichols 主译李廷玉; 副主译:李继斌, 魏小平: 译者: 李廷玉,李继斌, 陈立, 唐芳,魏小平, 赵勇, 练雪梅, 陈科, 宋萃, 张萱, 王丽, 荀泽丽, 人民卫生出版社, People’s Medical Publishing House.