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(阅读时间⼤约为4分钟。如果时间紧张，直接跳到⽂章最后的“摘要”。Approximate reading time 4 minutes. If short on time, skip to “Bottom Line” at the end. )
大卫·萨克特（David Sackett），被人称为“循证医学之父”，说过这样一句话：
David Sackett, often called the “father of evidence-based medicine”, once famously said:
“你在医学院学的东西在你毕业后五年内有⼀半将被证明是完全错误或者是过时的。但问题是没⼈能告诉你是哪⼀半。所以你最需要学的东西是如何自学。”
“Half of what you’ll learn in medical school will be shown to be either dead wrong or out of date within five years of your graduation; the trouble is that nobody can tell you which half–so the most important thing to learn is how to learn on your own.”
越来越清楚的是，有关胆固醇的知识和理论就属于那一半。
It is increasingly clear that the teachings and theories around cholesterol is just one of those half.
“胆固醇”这个词会不会让你⼼生恐惧？它会不会让你⻢上想到“心脏病”？动脉阻塞？
Does the word “cholesterol” instill some fear in you? Is the first association you make with cholesterol “heart disease”? Does it conjure up images of clogged arteries?
我就是这么理解的。所以我每年都会检查胆固醇，⽽且⾮常坚决地告诉 爸爸妈妈不要吃蛋⻩。
That was precisely my understanding. I diligently checked my cholesterol level and fervently advised my parents against eating egg yolk.
后来我发现我是错的。我们⼤多数⼈都是错的。你仍然需要知道你的胆固 醇⽔平，但它完全不像我们以前理解的那样是导致⼼脏病的因素。
Turns out I was wrong, almost all of us were wrong. Yes, you still need to know your cholesterol, but it is not nearly as big a factor in causing heart disease as we once thought.
先看下，什么是胆固醇？
First, what is cholesterol?
你可能会想到那种在我们血液中穿行，粘稠，给我们带来麻烦的东西。实际上，胆固醇存在与我们体内的每个细胞。它是我们身体运行不可或缺的一种油脂。它是制造体内众多重要物质的原材料：比如激素，尤其是性激素，包括雌激素，孕激素，和睾丸激素；维⽣素D；细胞膜；胆汁等。
You may imagine cholesterol as this sticky stuff that flows in the blood stream and cause trouble. It is actually in every cell of our body. It is a lipid essential for our biological functions. It is the raw material for building hormones, especially all the sex hormones, including estrogen, progesterone and testosterone. It is needed for making Vitamin D, for building cell membranes, for making bile.
我们的大脑对胆固醇也高度依赖。它对于神经细胞的形成和保护至关重要，正是这些神经⽹络可以让⼤脑与身体的其他部位进行交流。大脑只占体重的约2％，却使用25%的胆固醇。事实上，降低胆固醇的药物最严重的副作⽤之⼀就是记忆力减退。
Our brain is also highly dependent on cholesterol. It is essential for the development and protection of nerve cells, which enables the brain to communicate with the rest of the body. The brain takes up about 2% body weight, but around 25% of body’s cholesterol is found in the brain. In fact, one of the most serious side effects of cholesterol-lowering medication is memory loss.
我们体内的胆固醇约80%是身体自己制造的，其余的20%来⾃⻝物。
About 80% of cholesterol is produced by our body, and the rest is from food.
既然胆固醇对我们的健康如此重要，为什么它的名声却那么差？
If cholesterol is so vital for human health, why does it get such a bad rep?
⾼胆固醇⽔平与心血管疾病密切相关的理论可以追溯到1940年代由美国⽣理学家安塞尔·凯斯（Ancel Keys）领头的“七国研究”。它的结论在当时被广泛接受。但是，近年来，开始涌现出对这个研究的批评和争议。
The origination of the theory that high cholesterol level is directly correlated to high risk of cardiovascular diseases can be traced back to the Seven Countries Study in 1940s headed by Ancel Keys, an American physiologist. The conclusion was widely accepted at the time. But there have been loud criticism and controversy in recent years on that very study.
当动脉血管由于斑块破裂或阻塞而被切断血流时，心脏病就会发作。由于胆固醇是形成斑块和阻塞的物质，所以可以断定它是引起心脏病的罪魁祸首，不是吗？
Heart attacks happen when arteries are cut off blood flow due to plaque ruptures or clogs. Since cholesterol is the substance that forms the plaque and clog, it is for sure the culprit for causing the heart attacks and strokes, isn’t it?
听起来似乎很合理，但有⼀个重要的漏洞。这么说吧，你每次经过交通事故现场的时候都会看到⼀辆警⻋。看过很多类似的现场之后，你得出结论：警车引发交通事故。这和说胆固醇导致⼼脏病是⼀样的逻辑。
It sounds reasonable, except for one major flaw. Every time you pass an accident site, you see a police car. After this happens many times, you conclude that police car causes accidents. This is the same logic as saying cholesterol causes heart diseases.
胆固醇在动脉⾎管⾥形成斑块是有原因的。奥兹医生（Dr. Oz) 是美国著名的心脏病专家和脱口秀节目主持人。他把胆固醇称为⼈体的“石膏”。当血管出现凹陷时，胆固醇会赶过来进行修复。如果胆固醇质量⾼且凹陷不严重，那修复会顺利而且平整。但也可能会形成斑块。是什么原因造成这些凹陷呢？根据奥兹医生的说法，有三个最主要的原因：
There is a reason cholesterol is present in the artery. Dr. Oz, a famed cardiologist and talk show host in the US, calls cholesterol body’s “plaster”. When you have a hole in the blood vessel, cholesterol comes to repair it. If the cholesterol is of high quality and the hole is not serious, you get a smooth repair. It can also get ugly and and form plaques. But what causes the holes? According to Dr. Oz, there are three major culprits:
高血压
High blood pressure;
糖尿病
Diabetes;
抽烟
Cigarettes
许多人认为血管的阻塞程度是心脏病发作和中风的最大潜在问题。这并不完全正确。你可能会有60％的堵塞，而不会有任何问题。但有可能你只有30％的堵塞，但⼀旦破裂，你麻烦就大了。导致斑块破裂的原因才是心脏病的真正祸源，它就是我们在以前的⽂章写过的诸多慢性疾病的罪魁祸首：
Many people think of the plaque size as the problem for potential heart attacks and strokes. This is not entirely true. You could have 60% blockage and never have a problem. You could have 30% blockage and get in serious trouble if it ruptures. What causes the rupture is the real trigger of heart diseases and something we have talked about in our previous article as the main culprit for many chronic diseases :
炎症
Inflammation
⽊星试验是⼀项涉及1.7万多人的大型研究，最初是为了评估胆固醇正常但炎症⽔平⾼的相对健康的⼈是否可以从降低胆固醇的他汀类药物中获益。研究发现，那些胆固醇⾼但⽆炎症的⼈患心血管疾病的风险非常低；那些有炎症但胆固醇水平还可以的人则有着较高的风险；那些胆固醇和炎症都高的人风险最高。
The Jupiter Trial, a large study involving more than 17000 people, was originally designed to assess whether relatively healthy people with normal cholesterol but high level of inflammation may benefit from the cholesterol lowering drug statin. It has actually indicated that people who had high cholesterol but no inflammation had very low cardiovascular risk. The people who had high inflammation but kind of okay cholesterol were at higher risk. And those with high cholesterol and high inflammation had the most risk.
当前有关胆固醇的标准测试其实已经过时了，有时还会很误导。当我们做脂质测试时，通常会看这几个指标：总胆固醇，高密度脂蛋白（HDL），低密度脂蛋白（LDL）和甘油三酸酯。
The current standard testings on cholesterol are outdated and sometimes could be misleading. When we get a lipid test, usually we get these measures: total cholesterol, HDL, LDL and triglycerides.
HDL（高密度脂蛋白，通常称为“好胆固醇”）和LDL（低密度脂蛋白， 通常称为“坏胆固醇”）实际上不是胆固醇，而是胆固醇的载体。由于胆固醇不溶于水，所以需要⼀种运载工具。这些称为HDL和LDL的蛋白质将胆固醇从⼀个地方输送到另⼀个地方。
HDL (High Density Lipoprotein, usually called “good cholesterol”) and LDL (Low Density Lipoprotein, usually called “bad cholesterol”) are actually not cholesterol, rather they are the carriers of cholesterol. Because cholesterol is not water soluble, it needs a vehicle to carry them around to do its job, so these proteins called HDL and LDL transport cholesterol from one place to another.
传统的主流观点认为，高HDL和低LDL是健康的，反之则不健康。但这种以偏概全的做法错过了⼀些很重要的细节。HDL和LDL的数值只能给我们⼀部分信息。更重要的是这些蛋白质颗粒的大小和密度。换句话说，这个数值告诉你的基本上是胆固醇的重量，但它没有告诉你它是由5000个大颗粒还是10,000个小颗粒组成的。正是这些信息可以在很大程度上告诉你真正的风险。
The conventional wisdom is that a high HDL and low LDL is an indication of healthy lipid profile, and vice versa. But this broad brush misses some important details. The number of HDL and LDL is just one piece of information. What is even more important is the size and density of these protein particles. In other words, the number is basically telling you the weight of your cholesterol, but it does not tell whether it is made up of 5000 big particles, or 10,000 small particles. It is this information that is more revealing of your potential risk.
那些小而密的蛋白质是最危险的。如果你的是又大又蓬松的那种，则不会有什么问题。因此，医生可能会看到你的胆固醇是150，认为你完全没事，而实际上你可能有着很高的风险。事实上，研究发现，心脏病发作的人当中有超过50%的人有着完全正常的胆固醇！
Those small and dense proteins are dangerous. But if you have big and fluffy ones, it does not impose much risk. So your doctor may look at your cholesterol number of 150 and think you are completely fine when in fact you could have a very high risk. As a matter of fact, studies have found that more than 50% of people who have heart attacks have perfectly normal cholesterol levels!
下次做胆固醇测试时，让你的医生也测试⼀下胆固醇颗粒的大小。
Next time you have your cholesterol tested, ask to also test the size of your cholesterol particles.
另⼀个你可能关心的问题是，食用富含胆固醇的⻝物对我们的健康是不是很有害？这也是有争议的。有许多因素会影响我们的血液中胆固醇的含量，而食物只是其中之一。2015年，美国政府的饮食指南做了⼀个震惊公众的改变。它取消了长期以来对每天摄入300克胆固醇的限制，原因是：
Another question is, is eating cholesterol rich food dangerously bad for our health? This has also been disputed. There are many factors that influence your blood cholesterol, and food is just one of them. In 2015 the dietary guidelines from the US government made a change that shocked the public. It dropped its long held restriction on dietary cholesterol intake of 300 grams per day, because:
“没有足够的证据让我们对胆固醇的摄入有⼀个标准的限量。”
“Adequate evidence is not available for a quantitative limit for dietary cholesterol specific to the Dietary Guidelines.”
所有这些并不是要给你⼀个乱吃东西而不再关注胆固醇的通⾏证。胆固醇只是⼀个因素。很高的胆固醇对很多⼈来说仍然不是个好事。但是，我们现在知道，胆固醇是你健康状况的⼀个表现，而不是你健康状况的根源。因此，严格限制⻝物中的胆固醇来控制血液中的胆固醇并不是⼀个有效的方法。
All this is not to give you a pass for eating whatever you want and not caring about cholesterol level at all. It is just once piece of the puzzle. A very high number can still be bad. But what we know now is that it can be an INDICATION of some underlying conditions, but it is not the CAUSE of those conditions. So severely limiting cholesterol in your food to control the cholesterol in your blood is no longer a valid strategy.
科学界对胆固醇如何影响我们的健康的理解仍然在发展。但有⼀点很清楚，胆固醇绝不是我们的敌人。它对于我们的免疫和大脑的运行至关重要。不要再心怀惧怕。
Our understanding of how cholesterol influences our health is still evolving. But one thing is very clear, it is not our enemy. It is essential for our immune health and optimal functioning of our brain. It is not something to be afraid of.
摘要
Bottom Line:
胆固醇并不像我们理解的那样是心脏病的罪魁祸首。实际上，它并不是一个可靠的心脏病的预测指标。 高胆固醇是你健康问题的体现，而不是原因。没有足够的证据表明限制饮食里的胆固醇可以极大帮助你控制血液中的胆固醇。当前的标准脂质测试给出的信息并不完整。你不仅需要测试胆固醇的水平，还需要测试其颗粒的大小。
Cholesterol may not be the cause of heart diseases like we previously thought. It is actually a poor predictor for heart diseases. High cholesterol is more an indication of a health problem than the cause of the health problem. There is no sufficient evidence to support limiting dietary cholesterol intake for the purpose of controling blood cholesterol level. The current standard lipid testing is not complete. You should not only look at the level of your cholesterol, but also the particle size.
