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Friday 30 September 2011

Cholesterol 胆固醇

Cholesterol is a critically important compound in body cell of human and animal for cell growth and viability. Cholesterol found in food, our body also secretes cholesterol. Too much of cholesterol in the body may affect the health. Total cholesterol is the sum of HDL (high density lipoprotein), LDL (low density lipoprotein) and VLDL (very low density lipoprotein) which affect our body differently.
HDL (high density lipoprotein), considered "good" cholesterol, maintain peripheral vascular health.
LDL (low density lipoprotein), considered "bad" cholesterol, may cause hardening and blockage of the arteries
VLDL (very low density lipoprotein), "bad" cholesterol, harmful to our health.

Low density lipoprotein (LDL-Cholesterol) is 60% of the total cholesterol. Although our body need LDL-C, excessive LDL-C will go into arteries and form plaque, thereby cause high cholesterol and clog in blood vessel and cause coronary heart disease, cerebral infarction, myocardial infarction due to plaque rupture and other serious consequences.

There is another blood lipid named triglycerides, elevated blood triglycerides can increase LDL-C, it is the accomplice of LDL-C, and is a "timed-bomb" between LDL-C and the arterial wall. Arteries play important role in human body in carrying blood and oxygen to various organs in the body. The 'bad' cholesterol increase and if endothelial flawed due to high blood pressure, diabetes, smoking and other factors, it is prone to high cholesterol and will drill into the arterial endothelium following by the formation of atherosclerotic plaques.

Cholesterol Levels

Cholesterol levels are measured in milligrams (mg) of cholesterol per deciliter (dL) of blood in the United States and some other countries. Canada and most European countries measure cholesterol in millimoles (mmol) per liter (L) of blood. Consider these general guidelines when you get your cholesterol test (lipid panel or lipid profile) results back to see if your cholesterol falls in an ideal range.
Total cholesterol
U.S. and some other countries Canada and most of Europe
Below 200 mg/dLBelow 5.2 mmol/LDesirable
200-239 mg/dL5.2-6.2 mmol/L Borderline high
240 mg/dL and aboveAbove 6.2 mmol/LHigh
 
LDL cholesterol
U.S. and some other countries Canada and most of Europe
Below 70 mg/dLBelow 1.8 mmol/LIdeal for people at very high risk of heart disease
Below 100 mg/dLBelow 2.6 mmol/LIdeal for people at risk of heart disease
100-129 mg/dL2.6-3.3 mmol/L Near ideal
130-159 mg/dL3.4-4.1 mmol/LBorderline high
160-189 mg/dL4.1-4.9 mmol/L High
190 mg/dL and aboveAbove 4.9 mmol/LVery high
 
HDL cholesterol
U.S. and some other countries Canada and most of Europe
Below 40 mg/dL (men)
Below 50 mg/dL (women)		Below 1 mmol/L (men)
Below 1.3 mmol/L (women)		Poor
50-59 mg/dL1.3-1.5 mmol/LBetter
60 mg/dL and aboveAbove 1.5 mmol/LBest
 
Triglycerides
U.S. and some other countries Canada and most of Europe
Below 150 mg/dLBelow 1.7 mmol/LDesirable
150-199 mg/dL1.7-2.2 mmol/LBorderline high
200-499 mg/dL2.3-5.6 mmol/L High
500 mg/dL and aboveAbove 5.6 mmol/LVery high

The American Heart Association (AHA) recommends that a triglyceride level of 100 mg/dL (1.3 mmol/L) or lower is considered "optimal." The AHA says this optimal level would improve your heart health. However, the AHA doesn't recommend drug treatment to reach this level. Instead, for those trying to lower their triglycerides to this level, lifestyle changes such as diet, weight loss and physical activity are encouraged. That's because triglycerides usually respond well to dietary and lifestyle changes.

*Canadian and European guidelines differ slightly from U.S. guidelines. These conversions are based on U.S. guidelines.



What Affects Cholesterol Levels?

A variety of things can affect cholesterol levels. These are things you can do something about:
  • Diet. Saturated fat and cholesterol in the food you eat make your blood cholesterol level go up. Saturated fat is the main culprit, but cholesterol in foods also matters. Reducing the amount of saturated fat and cholesterol in your diet helps lower your blood cholesterol level.
  • Weight. Being overweight is a risk factor for heart disease. It also tends to increase your cholesterol. Losing weight can help lower your LDL and total cholesterol levels, as well as raise your HDL and lower your triglyceride levels.
  • Physical Activity. Not being physically active is a risk factor for heart disease. Regular physical activity can help lower LDL (bad) cholesterol and raise HDL (good) cholesterol levels. It also helps you lose weight. You should try to be physically active for 30 minutes on most, if not all, days.
Things you cannot do anything about also can affect cholesterol levels. These include:
  • Age and Gender. As women and men get older, their cholesterol levels rise. Before the age of menopause, women have lower total cholesterol levels than men of the same age. After the age of menopause, women's LDL levels tend to rise.
  • Heredity. Your genes partly determine how much cholesterol your body makes. High blood cholesterol can run in families.




胆固醇是人体细胞内所必须的成分之一，也是高等动物细胞生长和活力的必要因子。胆固醇可来自于食物，人体内也会合成，如果体内有过多的胆固醇含量，对健康则非常不利。此外，胆固醇在体内又可分为高密度脂蛋白（HDL）、低密度脂蛋白（LDL）、和极低密度脂蛋白（VLDL），对健康有不同的影响。
高密度脂蛋白（HDL）：又称为好的胆固醇，可维持周边血管的健康
低密度脂蛋白（LDL）：又称为坏的胆固醇，会造成血管硬化及阻塞
极低密度脂蛋白（VLDL）：属于坏的胆固醇，对健康不利

“坏”胆固醇(低密度脂蛋白胆固醇LDL-Cholesterol)占总胆固醇的约60%，尽管身体需要一定的LDL-C，但多余的LDL-C会钻入动脉血管内皮，形成斑块，从而，会出现胆固醇高的现象，进而堵塞血管引起冠心病、脑梗塞，或者随着斑块破裂引起心肌梗死、猝死等严重后果。

血里还有一种血脂叫甘油三酯，血中甘油三酯升高可以使LDL-C升高，所以它是LDL-C的帮凶，是LDL-C与动脉壁的“定时炸弹”。动脉在人体非常重要，它们把血液和氧输送到身体的各个重要器官。如果“坏”胆固醇增加，一旦高血压、糖尿病、吸烟等因素使内皮有漏洞，就很容易出现胆固醇高，它们就会钻到动脉的内皮下面，形成动脉粥样硬化斑块。

胆固醇指数

在美国与其它国家，胆固醇指数以每分升(deciliter-dL)血液中有多少毫克(miligrams-mg)的胆固醇为计。至于加拿大与其它欧洲国家，胆固醇指数则以每公升(liter-L)血液中有多少毫（milimoles-mmol）来测量胆固醇。当您接受胆固醇检测（血脂评估检测或分析）后，可根据这些准则来了解您的胆固醇状况是否理想。
总胆固醇
美国与其他国家加拿大与部分欧洲国家
低于 200 mg/dL低于 5.2 mmol/L理想
200-239 mg/dL5.2-6.2 mmol/L 高边缘
240 mg/dL 或以上6.2 mmol/L 或以上高
 
低密度脂蛋白胆固醇
美国与其他国家加拿大与部分欧洲国家
 70 mg/dL 以下 1.8 mmol/L 以下对于心脏疾病高风险者为理想水平
 100 mg/dL 以下2.6 mmol/L 以下对于心脏疾病存风险者为理想水平
100-129 mg/dL2.6-3.3 mmol/L 近乎理想
130-159 mg/dL3.4-4.1 mmol/L高边缘
160-189 mg/dL4.1-4.9 mmol/L 高
190 mg/dL 或以上4.9 mmol/L 以上非常高
 
高密度脂蛋白胆固醇
美国与其它国家加拿大与部分欧洲国家
男性 40 mg/dL 以下         女性 50 mg/dL 以下男性 1 mmol/L 以下
女性 1.3 mmol/L 以下		差
50-59 mg/dL1.3-1.5 mmol/L还好
60 mg/dL 或以上1.5 mmol/L 以上最佳
 
甘油三酯
美国与其它国家加拿大与部分欧洲国家
低于150 mg/dL低于 1.7 mmol/L理想
150-199 mg/dL1.7-2.2 mmol/L高边缘
200-499 mg/dL2.3-5.6 mmol/L 高
500 mg/dL 或以上5.6 mmol/L 以上非常高

美国心脏协会 (AHA) 建议，甘油三酯水平于100 mg/dL (1.3 mmol/L) 或更低为佳。他们认为这个水平可改善您的心脏健康。然而，美国心脏协会不鼓励药物治疗以达至以上水平。那些想要将甘油三酯水平减至以上标准，可作出生活习惯上的改变，如饮食习惯，减轻体重和体力运动。因为通常甘油三酯会因饮食习惯和生活习惯的改变而改善。

*加拿大及欧洲国家与美国的准则有些不同。以上转换基于美国准则。

 

影响胆固醇水平的因素

有许多因素可影响胆固醇水平。以下为您可以控制的因素：
  • 饮食。饱和脂肪和食物中的胆固醇可使您的血脂提升。饱和脂肪是罪魁祸首，食物中的胆固醇也相当重要。减低饱和脂肪含量和饮食中的胆固醇可助您降低血液中的胆固醇水平。
  • 体重。超重是心脏疾病的危险因素，往往也提升您的胆固醇水平。减肥可助您降低低密度脂蛋白和总胆固醇水平，同时提升高密度脂蛋白和降低甘油三酯水平。
  • 体力运动。缺乏体力运动也是心脏疾病的危险因素。经常运动可助您降低低密度脂蛋白（坏胆固醇）和提升高密度脂蛋白（郝胆固醇）的水平。
您无法控制但也会影响胆固醇水平的因素包括：
  • 年龄和性别。女性和男性随着年龄增长，胆固醇水平也相继增长。更年期前，女性的总胆固醇水平较同龄男性低。更年期后，女性的低密度脂蛋白水平趋于上升。
  • 遗传。家族基因在某种程度上操控您的胆固醇水平。高血脂因基因因素而引发。

 

Top 10 Foods Highest in Cholesterol  十大高胆固醇食物







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