Chapter 2 - What Is Cholesterol?
Cholesterol is a member of the large family of chemical compounds known as lipids (fats).
However, cholesterol is a separate, specialised type of lipid that is chemically different from fat. Cholesterol is a part of the subgroup called "sterols," whereas dietary and body fat are part of the subgroup "glycerol esters." There are two main categories of cholesterol. Dietary cholesterol comes from the animal-based food we consume and cannot be measured by a doctor. The other type of cholesterol is blood cholesterol, which is made in the liver. Although the two types are chemically identical, they are not representative of each other. The cholesterol levels that are measured at the doctor's office and referred to in most studies are blood cholesterol levels representative of liver function. ¹
第 2 章 - 什么是胆固醇？
胆固醇是脂质（脂肪）这一大类化学化合物的成员。
然而，胆固醇是一种单独的、特殊的脂质，在化学上与脂肪不同。胆固醇属于“固醇”亚组，而膳食和体脂属于“甘油酯”亚组。胆固醇主要分为两类。膳食胆固醇来自我们食用的动物性食物，医生无法测量。另一种胆固醇是血液胆固醇，由肝脏产生。虽然这两种胆固醇在化学上是相同的，但它们并不代表彼此。在医生办公室测量的胆固醇水平，以及大多数研究中提到的胆固醇水平，是代表肝功能的血液胆固醇水平。
Cholesterol is carried in the blood in the form of lipoproteins, lipids with proteins attached that act as an emulsifier.² Accumulation of cholesterol arises when low-density lipoproteins (LDL) deliver more cholesterol than needed to the cells and too few high-density lipoproteins (HDL) are available to carry it away from degenerating cells. The relative balance between these lipoproteins is determined by various factors including genetics, diet, stress and insulin resistance.
胆固醇以脂蛋白的形式存在于血液中，脂蛋白是一种脂质，上面附着有起乳化剂作用的蛋白质。² 当低密度脂蛋白 (LDL) 向细胞输送过多的胆固醇，而可用的高密度脂蛋白 (HDL) 又太少，无法将胆固醇从退化的细胞中带走时，就会发生胆固醇的积累。这些脂蛋白之间的相对平衡由遗传、饮食、压力和胰岛素抵抗等多种因素决定。
Low-density lipoproteins and very
low-density lipoproteins (VLDL) carry cholesterol toward tissues.
There is a demonstrated
relationship between the serum level of LDLs and the relative risk of coronary heart disease (CHD) in high-risk patients.' Of even greater importance, it is the oxidized LDL and VLDL that form the real risk factor. The smaller the molecule, the more easily it is oxidized, so the small LDL and VLDL are the targets of oxidation as are any small molecules in the blood. The LDL and VLDL cholesterol are oxidized in the blood due primarily to a low level of antioxidants and high level of oxidants (free radicals); the presence of these indicates poor diet and lifestyle. In contrast, high-density lipoprotein (HDL) carries cholesterol back to the liver and is associated with protection against cardiovascular disease. Cholesterol is associated with the risk of CVD, but it is not the disease.
低密度脂蛋白和极低密度脂蛋白 (VLDL) 将胆固醇运送到组织 ³, ⁴ 已证明 LDL 的血清水平与高危患者患冠心病 (CHD) 的相对风险之间存在关联。' 更重要的是，氧化的 LDL 和 VLDL 才是真正的风险因素。分子越小，越容易被氧化，因此小 LDL 和 VLDL 是氧化的目标，就像血液中的任何小分子一样。LDL 和 VLDL 胆固醇在血液中被氧化主要是由于抗氧化剂水平低和氧化剂 (自由基) 水平高；这些物质的存在表明饮食和生活方式不良。相反，高密度脂蛋白 (HDL) 将胆固醇带回肝脏并与预防心血管疾病有关。 胆固醇与心血管疾病的风险有关，但它并不是疾病。
胆固醇是一种症状，而不是疾病
Cholesterol is a symptom, not the disease
High cholesterol is a symptom of
an underlying health problem. It predicts less than 35% of cardiovascular disease. In fact, most heart attack and stroke events occur in individuals without elevated cholesterol. At least half of all cardiac arrests occur in people with normal cholesterol levels and 20% occur in people without any traditional risk factors.
Cholesterol is the messenger telling us that there is stress on the liver; cholesterol is not the killer it is made out to be.
Why aren't we told everything?
为什么我们没有被告知一切？
A significantly better (than
cholesterol) predictor of the risk of heart attack or stroke is the concentration of omega-3 oils in the blood. The higher the concentrations, the lower the risks. Omega-3 concentrations predict up to 90% of CVD compared to a 35% prediction rate from cholesterol readings. But there is no money to be made in prescribing omega 3 oils. Omega-3 oils also reduce triglycerides and other risk factors for CVD, as well as reducing the risk of many other forms of chronic illness- from Alzheimer's to arthritis and cancer. This is due to the anti-inflammatory effect of fish oils.
Fish oils have only positive side effects and far outweigh any benefit from statin drugs.
比胆固醇更能准确预测心脏病发作或中风风险的指标是血液中 omega-3 油的浓度。浓度越高，风险越低。omega-3 浓度可预测高达 90% 的 CVD，而胆固醇读数的预测率为 35%。但开 omega 3 油的处方是赚不到钱的。omega-3 油还能降低甘油三酯和其他 CVD 风险因素，并降低许多其他形式慢性疾病的风险——从阿尔茨海默氏症到关节炎和癌症。这是由于鱼油的抗炎作用。
鱼油只有积极的副作用，远远超过他汀类药物的任何好处。
There are many more indicators in addition to cholesterol
除了胆固醇之外，还有很多其他指标
Another marker of inflammation
in the body is C-reactive protein (CRP).
C-reactive protein is a better predictor of CVD than cholesterol. People with elevated CRP run twice the risk of dying from cardiovascular-related problems compared to those who have elevated cholesterol levels.
However, CRP is just a marker and, like cholesterol, it is not the cause. We want to get CRP lower but not by a drug that lowers CRP only; we want to lower it by lowering inflammation. When inflammation is reduced, one result is CRP comes down.
体内炎症的另一种标志物是 C 反应蛋白 (CRP)。C 反应蛋白比胆固醇更能预测心血管疾病。与胆固醇水平升高的人相比，CRP 升高的人死于心血管相关问题的风险是前者的两倍。然而，CRP 只是一个标志物，和胆固醇一样，它不是病因。我们希望降低 CRP，但不是通过仅降低 CRP 的药物；我们希望通过降低炎症来降低它。当炎症减少时，结果之一就是 CRP 下降。
C-reactive protein is produced in
the liver and other tissues in response to inflammation anywhere in the body. It is manufactured as part of the body's immune response against infection and injury, but this response can cause damage if it produces excess and chronic inflammation. CRP levels are improved by the same factors that improve cardiovascular health: exercise, good diet, maintaining a healthy weight and not smoking. One study demonstrated that supplementing with 500 milligrams (mg) of vitamin C reduced CRP by 25%, while numerous other studies have shown that
supplementing with vitamins and minerals also reduces CRP and the inflammatory process.
C-反应蛋白是在肝脏 和其他组织中产生的，以响应身体任何部位的炎症。它是身体对抗感染和损伤的免疫反应的一部分，但如果产生过量和慢性炎症，这种反应可能会造成损害。改善 CRP 水平的因素与改善心血管健康的因素相同：运动、良好的饮食、保持健康的体重和不吸烟。一项研究表明，补充 500 毫克 (mg) 维生素 C 可将 CRP 降低 25%，而许多其他研究表明，补充维生素和矿物质也可以降低 CRP 和炎症过程。
So what is the problem?
那么问题是什么？
One possibility is that our diets are
deficient in nutrients — such as
omega-3 oils from fish as well as vitamins and antioxidants — needed to maintain a healthy balance between inflammatory and anti-inflammatory responses. Researchers have also found that low levels of vitamin D are linked to higher levels of inflammation markers such as -reactive protein. Interestingly, extensive research has shown a direct inverse correlation with vitamin D levels and the risk of cardiovascular disease; a
serious problem is that many people are now deficient in vitamin D. 一种可能性是，我们的饮食缺乏维持炎症和抗炎反应之间健康平衡所需的营养物质——例如来自鱼类的 omega-3 油以及维生素和抗氧化剂。研究人员还发现，维生素 D 水平低与 C 反应蛋白等炎症标志物水平较高有关。有趣的是，大量研究表明，维生素 D 水平与心血管疾病风险呈直接负相关；一个严重的问题是，现在许多人缺乏维生素 D。一种可能性是，我们的饮食缺乏维持炎症和抗炎反应之间健康平衡所需的营养物质——例如来自鱼类的 omega-3 油以及维生素和抗氧化剂。研究人员还发现，维生素 D 水平低与 C 反应蛋白等炎症标志物水平较高有关。有趣的是，大量研究表明，维生素 D 水平与心血管疾病风险呈直接负相关；一个严重的问题是，现在许多人缺乏维生素 D。
It's all in the liver
一切都在肝脏里
Along with other signaling molecules, insulin controls the production of fats such as cholesterol and triglycerides. It also controls the packaging of cholesterol and triglycerides into LDL, VLDL, HDL and other lipoproteins. Glucagon inhibits the enzyme HMG-CoA
reductase that creates VLDL and
LDL cholesterol; insulin activates the enzyme. To control cholesterol production, it is important to increase glucagon and decrease insulin. The result of eating more sugar or processed carbohydrates (or other high-GI foods such as white bread and breakfast cereals) is the production of more insulin hormone.
Increased insulin stimulates more HMG-CoA reductase enzyme and,
as a consequence more
cholesterol and triglycerides are
produced. Simple carbohydrates are the main culprits. We have known this since the early 1970s and there are hundreds of studies since that show the higher the GI, the higher the cholesterol. One study in 1976 of more than 2,000 school children found that those on a high-sugar diet had elevated cholesterol; the study predicted that the high sugar group had a higher future risk of heart attack and stroke. People with type 2 diabetes have elevated fasting insulin as well as elevated cholesterol and are two to four times as likely to have coronary heart disease (CHD) as a person without diabetes.¹⁹ In fact, elevated fasting insulin is a better predictor of cardiovascular
disease than cholesterol. Glucagon, when present in the bloodstream, lowers insulin levels. Glucagon is released every time you eat lean protein, especially from fish and plant sources.
胰岛素与其他信号分子一起控制脂肪（如胆固醇和甘油三酯）的产生。它还控制胆固醇和甘油三酯转化为 LDL、VLDL、HDL 和其他脂蛋白的过程。胰高血糖素会抑制产生 VLDL 和 LDL 胆固醇的 HMG-CoA 还原酶，而胰岛素会激活这种酶。为了控制胆固醇的产生，增加胰高血糖素和减少胰岛素非常重要。吃更多糖或加工碳水化合物（或其他高 GI 食物，如白面包和早餐麦片）会导致产生更多的胰岛素激素。
胰岛素增加会刺激更多的 HMG-CoA 还原酶，从而产生更多的胆固醇和甘油三酯。简单的碳水化合物是罪魁祸首。 我们早在 20 世纪 70 年代初就知道这一点，此后有数百项研究表明 GI 越高，胆固醇越高。1976 年的一项对 2,000 多名学童的研究发现，高糖饮食的孩子胆固醇升高；该研究预测，高糖饮食组未来患心脏病和中风的风险更高。2 型糖尿病患者的空腹胰岛素和胆固醇都升高，患冠心病 (CHD) 的可能性是非糖尿病患者的两到四倍。¹⁹事实上，空腹胰岛素升高比胆固醇更能预测心血管疾病。当血液中存在胰高血糖素时，会降低胰岛素水平。每次吃瘦肉蛋白质，尤其是来自鱼类和植物来源的蛋白质时，都会释放胰高血糖素。
There is also strong evidence to
show that stress increases a person's inflammatory markers and cholesterol. Not to mention increasing the levels of cortisol and their risk of heart attack and stroke. One possibility may be that stress encourages the body to produce more energy in the form of metabolic fuels, e.g., fatty acids and glucose. These substances require the liver to produce and secrete more LDL, which is the principal carrier of cholesterol in the blood. Both adrenaline and cortisol trigger the production of cholesterol. Cortisol has the additional effect of releasing more sugar into the blood, which increases the insulin and, as a consequence, increases LDL cholesterol. To highlight the importance of this, we also know that there is a strong association between stress and cardiovascular disease. The higher the stress, the higher the risk of CVD. Stress causes inflammation in the body, and inflammation is the underlying cause of heart attack and stroke. Stress is probably the single biggest causal factor in cardio vascular disease and linked to just about every other form of chronic illness. So why are we worrying about cholesterol?
还有强有力的证据表明 压力会增加人的炎症标志物和胆固醇。更不用说增加皮质醇水平和心脏病发作和中风的风险。一种可能性是压力促使身体以代谢燃料的形式产生更多的能量，例如脂肪酸和葡萄糖。这些物质需要肝脏产生和分泌更多的低密度脂蛋白，而低密度脂蛋白是血液中胆固醇的主要载体。肾上腺素和皮质醇都会触发胆固醇的产生。皮质醇还有一个额外的作用，就是向血液中释放更多的糖，这会增加胰岛素，从而增加低密度脂蛋白胆固醇。为了强调这一点的重要性，我们还知道压力和心血管疾病之间存在密切的联系。压力越大，心血管疾病的风险就越高。压力会导致身体发炎，而炎症是心脏病发作和中风的根本原因。 压力可能是导致心血管疾病的最大单一因素，并且与几乎所有其他形式的慢性疾病有关。那么我们为什么要担心胆固醇呢？
Elevated homocysteine is also linked to CVD disease. Homocysteine accrues in harmful amounts in people who
are unable to metabolize the
amino acid methionine.
Methionine is abundant in meat,
so reducing meat intake lowers homocysteine levels in these
people, as does taking B vitamins such as folate and vitamin B12.
This is actually not news: the homocysteine-artery disease link
was discovered back in 1969
Elevated fibrinogen in the blood,
another indicator of inflammation,
is linked to an increased risk of
stroke, heart attack and
cardiovascular death. Fibrinogen
is a protein involved in clotting,
and it seems to make platelets
stick more readily to atherosclerotic plaques or to
form clots when these plaques
rupture. The aim is not to find a
drug to reduce fibrinogen but to
lower inflammation through a
healthy diet and lifestyle. Trying
to lower just one or two of the
indicators is like shooting the messenger. It does not work.
There are many indicators of CVD
and that is what they are, just
indicators. Don't shoot the
messenger. Take action to
reduce your stress and improve
you diet and lifestyle. As you
read on the next chapters you
will see the answer lies not in a
drug that does not work or rely
on research funded by the drug companies, but what you can do
to change your life.
No comments:
Post a Comment