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我对营养的研究彻底击垮了很多我⻓久坚信的健康理念。牛奶就是其中之⼀。尽管我对牛奶中的乳糖敏感，但还是曾经每天喝不含乳糖的⽜奶。我甚至督促爸妈要多喝牛奶，因为我相信⽜奶是营养最丰富的食物之⼀。西方国家的人普遍比亚洲人高，这与他们喝很多牛奶有关系吧？
My research and learning in nutrition has shattered many of my long-held beliefs. Milk is one of them. I used to drink lactose-free milk every day, even though I was intolerant to regular milk. I urged my parents to drink milk as I believed it is one of the most nutrition dense foods out there. People in western countries are taller than Asians in general, doesn’t that have to do with the fact that we did not drink as nearly as much milk as they did?
结果我发现，真相比我以为的要复杂很多。是的，小孩子喝牛奶有可能会长得更高更快，但要付出的代价会足以让你三思。
Turns out the reality is so much more complicated than what I thought. Yes, drinking milk as a child can stimulate growth and make you potentially taller, but not without paying a hefty price.
⽜奶和骨骼健康
Milk and Bone Health
为什么大多数⼈认为牛奶营养丰富？除了蛋⽩质，应该就是钙了，对吧？喝牛奶可以提供很多的钙，促进骨骼健康，有效预防骨质疏松。这难道不是所有的专家都认可的吗？这难道不是基本常识吗？
Why do people think milk is nutritious? Aside from protein, it’s all about calcium, right? Drinking milk ensure we have adequate calcium and strong bones to prevent us from getting osteoporosis. After all, isn’t that what the authority tells us and isn’t that common knowledge?
做好震惊的准备。
Embrace for shock.
⼀个叫做护士健康研究的报告追踪了超过12万名年龄在三十至五十五岁的妇⼥长达十二年，发现没有证据表明喝牛奶可以防止髋部或前臂骨折。实际上，情况恰恰相反。每天至少喝三杯牛奶的女性的骨折发⽣率比不喝或少喝牛奶的女性要⾼。
Nurses’ Health Study, which followed 121,701 women aged thirty to fifty five for twelve years, found there was no evidence that consumption of milk protects against hip or forearm fractures. In fact, it was quite the opposite. Women who drank three or more servings of milk a day had a slightly higher rate of fractures than women who drank little or no milk.
⼤卫·路德维希是⼀名医学博士和医⽣，对饮⻝和新陈代谢关系的研究超过25年。他是哈佛医学院的儿科学教授和哈佛⼤学公共卫⽣学院的营养学教授。与他的哈佛同事沃尔特·威利特一起，他们深入分析了100多项研究，得出以下结论：
David Ludwig, a MD and PhD, has studied the effects of dietary composition on metabolism for more than 25 years. He is a professor of Pediatrics at Harvard Medical School and Professor of Nutrition at Harvard School of Public Health. Together with his Harvard colleague Walter Willet, they examined over 100 studies and made this conclusion:
“喝⽜奶最常见的健康原因是加强⻣骼，做“钙的储备”，防⽌骨折。这些似乎都不是真的。”
“The most common health reason for drinking milk is to strengthen bones, to create a “bank” for calcium throughout life and prevent fractures. None of this seems to be true.”
他们的发现与“护士健康研究”相呼应：“值得注意的是，⽜奶消费量最⾼的国家（比如瑞典） 往往⽐那些牛奶消费量最低的国家发生髋部骨折的风险更⾼。”
What they found echos Nurses’ Health Study: “Remarkably, countries with the highest milk consumption, like Sweden, tend to have a higher risk for hip fracture than those with the lowest consumption”.
下图显示了两者的相关性。X轴是整个卡路里摄⼊中牛奶的比例，Y轴是髋部骨折的发⽣率（每年10万人）。其中关系显而易见。
The following graph shows the correlation. X-axis is proportion of calorie intake from milk, Yaxis is hip fracture rate (100k person per year). This is pretty self evident.
几年前，我无意中看到了挪威官⽅卫⽣机构（挪威公共卫⽣研究所）的⼀篇文章，描述了⼀个令人费解的现象：在所有发达国家中，挪威女性的髋部骨折发⽣率最高。为了搞清楚这是为什么，政府正在资助⼀些关于维⽣素的研究。
Several years ago, I came across an article from Norway’s official health institution: Norwegian Institute of Public Health. It described a puzzling phenomenon: the hip fracture rate of women in Norway is the highest among all industrialized countries, and the government was funding research on certain vitamins to see if that could be reasons.
我因为以前的⼯作曾经去过挪威很多次，⽬睹了我的前同事们如何像喝水⼀样地喝牛奶。牛奶在公司的餐厅是免费提供的。几乎每个⼈的餐盘边都放着⼀杯牛奶。政府怎么可能对牛奶和骨折之间的关系毫⽆概念？我甚⾄给他们写了封信，建议他们研究下牛奶的摄⼊量。当然我并没有收到任何回音。但这进⼀步加强了我对⽜奶的不信任。
I had visited Norway many times with my previous job. I’ve seen how my former colleagues drank milk like water, which was offered free of charge in the company’s cafe. Almost everybody has a glass of milk beside their lunch plate. How on earth can the government have no clue milk consumption may have something to do with the high hip fracture rate? I actually wrote to the institute and suggested they look into it. Of course I never heard back. But this further reinforced my distrust in milk.
但这是为什么呢？⽜奶含钙量那么高，为什么反到对骨骼有坏处呢？
But why? Why does milk, with that much calcium, could actually be detrimental to your bone health?
⾸先，牛奶中的钙我们是不能完全吸收的，可以吸收的⼤约是30%。
First of all, we don’t absorb all the calcium in the milk. The absorption rate is about 30%.
更为重要的是，⽜奶中的蛋⽩质，实际上所有动物蛋⽩质，往往会让身体形成⼀种过酸的状态， 称为代谢性酸中毒，这意味着⼈体中的酸性过⾼。我们的身体需要⼀直保持化学平衡。为了抵消过量的酸，身体会释放最容易获得的缓冲酸性的东⻄：我们⻣骼中的钙。当钙从⻣骼中释放来维持身体的化学平衡的时候，我们的⻣骼却因此变得脆弱。
More importantly, the protein from milk, actually all animal protein in general, tends to create an acid-like condition in the body called metabolic acidosis, meaning the body has too much acid. Our body is always trying to maintain a chemical balance. To offset the excess acid, it draws upon the most readily available acid buffer: calcium in our bones. As this happens, the calcium is extracted from bones, thus our bones get weakened.
福尔曼医⽣在他“Eat To Live’⼀书中这么解释：
Dr. Furhrman also explained this in his book “Eat To Live”:
“动物产品中的硫基氨基酸极⼤地促进了尿酸的产⽣，导致钙的流失”，也就是说，动物蛋⽩质的摄⼊会让我们通过尿液流失⼀部分钙。"
“The sulfur-based amino acids in animal products contribute significantly to urinary acid production and the resulting calcium loss”, which means, we lose calcium through urination."
激素
Hormones
⽜奶的第⼆⼤问题是它所含的激素。⽜奶中含有约60种⾃然产⽣的激素，这还不包括⼈们出于各种⽬的往⽜身上注⼊的那些激素，也不包含奶⽜在孕期挤奶⽽产⽣的激素。这些激素⼀旦进⼊⼈ 体，便会⼲扰我们的各种⾃然愈合机制，损害我们的健康。这种损害有可能不是以⼀种急性或爆炸性的疾病呈现，更可能是以⼀种慢性的，存在你认知范围之外的⽅式来⼲扰你。著名的功能医学医⽣⻢克·海曼对这⼀现象深为了解：
The second problem I have learned about milk is all its hormones. Milk has about 60 naturally occurring hormones, and this number does not even include those hormones that people pump into cows for various purposes, or the hormones as a result of being milked while pregnant. Once in our bodies, these hormones can interfere with our natural healing mechanism and wreak havoc on our health, not in acute or explosive kind of way, but in a more subtle, fly-under-the-radar type of fashion. Mark Hyman, a famous functional medicine doctor, has seen this first hand:
“作为功能医学医⽣，我所面临的挑战之⼀是很多病⼈会有慢性炎症问题和慢性消化问题，胃酸反流，肠易激，或炎症性肠病。病⼈会有过敏，哮喘，湿疹，⿐充⾎，⿐后滴涕和其它⿐窦问题。他们还会有粉刺等等。从业这么多年来，我发现⼀个⾮常清晰的规律，我想许多其它功能学医⽣也⼀样，如果我让这些病⼈停止⼀切乳制品的摄入，很多症状都会自己好起来。“
“One of the challenges that I see as a functional medicine doctor is people come in with chronic inflammatory problems and chronic digestive problems, reflux, irritable bowel, worse, or inflammatory bowel disease. And they come in with allergies, and asthma, eczema, and congestion, post-nasal drip and sinus issues. They come in with acne and all of these issues. Over the years, there’s been a real clear pattern in my practice, and I think many other functional medicine doctors, that if you take people off dairy, a lot of these problems get better.”
所以，如果你有上述的这些慢性症状，⽽且好像总是治不好，不妨试⼀试停⽌⼀切奶制品，看会不会有⽤。
So if you suffer from the same chronic conditions mentioned above and nothing seems to work, it’s worthwhile to try to cut off dairy completely from your diet and see what happens.
癌症
Cancer
当然，牛奶促发癌症的可能更是让⼈担忧。
Then, there is the possible role milk plays in promoting cancer.
已经有不少的研究表明，⽜奶摄⼊量与癌症之间可能存在联系。这么多的证据⾜以让⼈谨慎。引⽤富尔曼医⽣的话：
There have been numerous studies that have shown the possible link between milk intake and cancer. The evidence is ample to justify caution. Quoting Dr. Furhman:
“2000年4⽉，《医师健康研究》的⼀份报告说，每天⻝⽤2.5份乳制品可使前列腺癌的⻛险增加 30％以上。在希腊进⾏的另⼀项对照研究表明，乳制品与前列腺癌之间有很强的联系……凯瑟琳 ·费尔菲尔德博⼠和她的同事们的研究发现，摄⼊乳糖量最多（每天⼀份或多份乳制品）的⼥性患各种侵袭性卵巢癌的⻛险要⽐摄⼊最少乳糖（每⽉三份或更少的⼥性）⾼44％。”
“In April 2000 the Physician’s Health Study reported that having 2.5 servings of dairy each day boosted prostate cancer risk by more than 30%. Another controlled study conducted in Greece has shown a strong association between dairy products and prostate cancer…… Dr. Kathleen Fairfield and her associates reported that women who consumed the highest amount of lactose (one or more servings of dairy per day) had a 44 percent greater risk for all types of invasive ovarian cancer than those who ate the lowest amount (three or fewer servings monthly)”.
科林·坎贝尔拥有康奈尔⼤学营养，⽣物化学和细菌学的博⼠学位，他对饮⻝与疾病（尤其是癌症）之间的关系的研究已有60多年了。他其实是在⼀个奶牛场长大的，他的家⼈以这个牛场为生。但他在对乳制品和动物蛋⽩进⾏了多年研究之后，开始反对这个他的家⼈曾经赖以为⽣的东西：牛奶。
Dr. Colin Campbell held a PHD from Cornell University on Nutrition, Biochemistry and Bacteriology, and has studied the relationship between diet and diseases, especially cancer, for more than 60 years. He actually grew up on a dairy farm where his family depended on milking cows for a a living. But after the research he has done on dairy and animal protein in general, he turned his back on the very thing that supported his upbringing.
纪录片《多⽤叉少⽤刀》对我个⼈健康观念的扭转⾄关重要。在纪录⽚⾥，坎⻉尔博⼠描述了他曾经在小白鼠身上做的⼀项实验。
In the documentary “Forks over Knives”, which profoundly changed my views on food and health, Dr. Campbell described one of the experiments he did on rats.
乳制品中的主要蛋⽩成分称为酪蛋⽩。在实验中，卡贝尔博⼠给⼀半的小白鼠喂养了20%酪蛋⽩ （20％的卡路⾥来⾃酪蛋白），另⼀半则喂养了5％的酪蛋⽩。在12周的时间⾥，喂养了20%酪蛋⽩的⼩⽩⿏的肝癌早期⽣⻓明显加快，⽽5％组则没有任何癌症迹象。然后，他每隔三周进⾏⼀次饮⻝切换（三周5%酪蛋⽩，三周20%酪蛋⽩）。他的发现令⼈震惊。每当给老鼠喂⻝20％ 的酪蛋⽩时，肿瘤就会有爆炸性的发展，而当给同⼀只老鼠喂5％的酪蛋⽩时，肿瘤的生长就会下降。
The main protein in dairy products is called casein. In the experiment, Dr. Campbell fed half of the rats a diet of 20% casein (20% of their calories from casein), and the other half 5% casein. Over the 12 weeks of the study, the rats eating the higher casein diet had a greatly enhanced level of early liver cancer tumor growth, while the 5% group did not have any sign of cancer. Then, he switched their diets back and forth between 5% and 20% dairy protein at a three-week interval. What he found was shocking. Whenever the rats were fed 20% of dairy protein, the tumor growth exploded, and when the same rats were given 5% dairy protein, tumor growth actually went down.
上面提到的路德维希博士在他的研究中也发现了牛奶与癌症之间的可能关联：
Dr. Ludwig also found possible links between milk consumption and cancer in his research:
”在成年⼈中，牛奶所含的生长因⼦可能会刺激与癌症有关的⽣物系统。尽管数据尚不清楚，但似乎有证据表明，大量食用乳制品会引起男性前列腺癌，尤其是侵袭性的前列腺癌和⼦宫内膜癌。“
“in adults, these growth factors (of milk) that may be stimulating biological systems that relate to cancer. While the data are not clear yet, there seems to be evidence of high levels of dairy consumption causing prostate cancer in men, especially aggressive forms of prostate cancer and endometrial cancer.”
从进化的⻆度来说, ⼈类根本不需要任何奶制品。消化奶制品所需的酶（乳糖酶）通常只有婴儿才会有，人长大之后就会消失。这就是为什么许多人（尤其是亚洲⼈）有乳糖不耐症。牛奶的唯一目的是让⼩⽜犊迅速成⻓为⺟⽜，所以充满了⽣⻓激素。乳蛋⽩可增加⾎液中IGF-1（胰岛素样⽣⻓因⼦）的含量。而IGF-1可以刺激正常细胞和癌细胞的生长。
In terms of evolution, humans have no requirement for dairy products. The enzyme required to digest dairy, lactase, are normally only present in infants, and then will go away in adults. That’s why many people, especially Asians, are lactose intolerant. Cow milk’s sole purpose is to get a baby calf grow into a cow quickly. It is full of growth hormones. Dairy protein boosts the amount of IGF-1（Insulin-like Growth Factor) in the blood. And IGF-1 is known to stimulate the growth of both normal and cancer cells.
⽜奶和癌症之间的这种可能联系我有亲⾃⽬睹。我的⼀个亲⼈在很⼩的时候就得了淋巴瘤。他从小到大几乎每天都喝⽜奶。我不能确切地说这是否或在多大程度上促发了他的病症，但这⾜以让我对牛奶保持⾼度怀疑。
This possible link between milk and cancer has hit very close to home for me. A family member got lymphoma at a very young age. He had been drinking cow milk all his life ever since he was little, almost on a daily basis. I cannot say for sure whether or how much this has contributed to his cancer, but it’s enough to make me suspicious.
总结
Bottom Line
是的，奶制品中含有钙, 对健康有⼀定的好处，但是你⾄少应该了解它具有的风险。而且，我们有那么多更好的来获取钙的方法！（以后再详细讲）如果你决定喝牛奶和吃奶制品，我强烈建议选择全脂而不是低脂（同样，以后再进⾏探讨），并尽量减少摄⼊量。
Yes, dairy contain calcium and could provide certain benefits, but you should also be aware of the risks. Plus, there are so many better options to get enough calcium! (More about this later) If you do decide to drink milk and eat dairy, I strongly suggest you go with full fat instead of low fat (again, let’s explore this with another post), and limit the amount.
⽜奶绝不是⼤⾃然的完美⻝物，除⾮你是⼀个小牛犊。
Milk is by no means nature’s perfect food, unless you are a baby calf.
References:
• Hyman, Mark; Ludwig, David. Why Most Everything We Were Told About Dairy Is Wrong
• Ludwig, David. Time to Question Everything You Know About Milk
• Forks Over Knives
• Fuhrman, Joel. Eat to Live
• D Feskanich, W C Willett, M J Stampfer, G A Colditz. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study
• Ramina Jajoo, Lingyi Song, Helen Rasmussen, Susan S Harris, Bess Dawson-Hughes. Dietary acidbase balance, bone resorption, and calcium excretion
• Norie Kurahashi 1 , Manami Inoue, Motoki Iwasaki, Shizuka Sasazuki, And Shoichiro Tsugane. Dairy product, saturated fatty acid, and calcium intake and prostate cancer in a prospective cohort of Japanese men
• Susanna C Larsson, Nicola Orsini, Alicja Wolk. Milk, milk products and lactose intake and ovarian cancer risk: a meta-analysis of epidemiological studies
