About hypercholesterolemia:
I. Hyperlipidemia
The blood includes cholesterol, phospholipids, triglycerides and fatty acids, all of which are lipid substances in the blood. Cholesterol and other plasma lipids are present in the blood in the form of complexes with apolipoproteins, but fatty acids are bound to albumin.
What is commonly referred to as hyperlipidemia is primarily elevated blood cholesterol and/or triglycerides. Hyperlipidemia is a manifestation of abnormal fat metabolism in the body. There are three main categories: hypercholesterolemia, hypertriglyceridemia, and mixed hyperlipidemia. Which indicators do we look at when we take the test results to determine if we have hyperlipidemia? The main indicators are serum cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-c), and low-density lipoprotein cholesterol (LDL-c). The following is a reference table of normal, critical, and treatment-needed levels for these indicators.
Hyperlipidemia usually has no obvious symptoms when it is not complicated by other diseases, so it should not be taken seriously and is often discovered during physical examinations or other tests.
II. Lipoproteins
Cholesterol and triglycerides are fats that, like oil, cannot be dissolved in the blood. In order for cholesterol to be transported in the blood, water-insoluble lipids combine with proteins to form lipoproteins and dissolve in the blood. There are several major forms of lipoproteins in the blood called HDL, LDL and very low density lipoproteins.
Reference table of hyperlipidemia test indicators
Name of lipid Normal level (mg%) (mg mole %) Critical level (mg%) (mg mole %) Level requiring drug treatment (mg%) (mg mole %)
Cholesterol <200 <5.17 200～239 5.17～6.12 ≥240 ≥6.18
Triglycerides <130 <1.47 130～159 1.47～1.80 ≥160 ≥1.81
Low-density lipoprotein cholesterol <130 <3.36 130～159 3.36～4.13 ≥160 ≥4.14
High-density lipoprotein cholesterol >45 >1.16 36～45 0.93～1.16 ≤35 ≤0.91
(I) Low-density lipoprotein
LDL mainly carries cholesterol, which can be used to synthesize cell membranes and steroid hormones. LDL cholesterol is also called “bad cholesterol” because LDL is the main atherogenic particle. Oxidized or chemically modified LDL-cholesterol cannot be used by tissues and cleared by the liver, and will be deposited on the arterial walls to form plaques, causing atherosclerosis. In healthy people, 2/3 of LDL particles are cleared by LDL receptors in the liver, but long-term intake of high-fat and high-cholesterol foods can inhibit the activity of LDL receptors and increase LDL-cholesterol levels.
A large number of animal and human studies have shown that elevated LDL-cholesterol can cause coronary heart disease and that lowering LDL-cholesterol can reduce the risk of coronary heart disease. The level of total cholesterol in the blood generally reflects the level of LDL-cholesterol. Clinical trials have shown that every 1% reduction in total cholesterol reduces the incidence of coronary heart disease by 2 to 3%.
LDL-cholesterol can be calculated by the formula
LDL-cholesterol (mg%) = total cholesterol – triglycerides / 5-HDL-cholesterol (mg%)
LDL-cholesterol (mg mole %) = total cholesterol – triglycerides / 2.2 – HDL-cholesterol (mg mole %)
If your LDL-cholesterol is less than 130 mg%, the ideal range, you should have your LDL-cholesterol levels reviewed every 5 years while maintaining a healthy diet, regular physical activity, and weight control to keep your LDL-cholesterol levels in the normal range. If your LDL-cholesterol is greater than or equal to 160 mg%, you will need to see your doctor to take medications, consume foods low in saturated fatty acids and cholesterol, engage in regular physical activity, and control your weight to lower your cholesterol levels. If your LDL-cholesterol level is between 130 and 159 mg%, the decision to take medication will depend on the presence of other risk factors for coronary heart disease, mainly cholesterol-lowering diets, regular physical activity and weight control measures.
(B) High-density lipoprotein
HDL is secreted mainly by the small intestine and liver and contains less cholesterol. The newly secreted HDL precursors take up the unesterified cholesterol from the renewed cell membranes and esterify the cholesterol to become the mature HDL. HDL can transfer cholesterol from surrounding tissues to the liver for elimination, thus preventing cholesterol from depositing on the arterial walls and forming plaques, which plays a role in cardiovascular protection. Therefore, HDL cholesterol is called “good cholesterol”. The higher the HDL cholesterol level in the body, the better the body’s ability to remove cholesterol and the lower the risk of cardiovascular disease.
A normal HDL-cholesterol level should be greater than 45 mg, with an average HDL-cholesterol level of about 45 mg for men and 55 mg for women, and those with HDL-cholesterol levels less than 35 mg have a higher risk of developing coronary heart disease.
How about raising HDL-cholesterol levels? It is mainly by exercising, 3 to 5 times a week for 30 minutes each time, you can raise HDL-cholesterol level. A small amount of wine consumption can also raise HDL-cholesterol levels, but too much alcohol consumption can lead to increased blood pressure and liver damage, so active exercise is the best measure to raise HDL-cholesterol.
(iii) Triglycerides
Our body fat is mainly stored in adipose tissue in the form of triglycerides. Only a small percentage of triglycerides are in the blood stream. High triglycerides alone do not necessarily cause atherosclerosis, but some triglyceride-rich lipoproteins also contain cholesterol, which can cause an increased risk of coronary heart disease.
III. Factors affecting blood cholesterol levels
Cholesterol levels in the body are not only related to diet, but also determined by our own cholesterol synthesis and metabolism ability. In fact, our own cholesterol synthesis is sufficient to meet our body’s needs and there is no need to consume more cholesterol. The main factors that cause elevated blood cholesterol are
(i) Genetic factors
The influence of human genes on blood cholesterol levels depends on the rate of cholesterol synthesis and removal. Approximately one in 500 people suffer from familial hypercholesterolemia, often with premature coronary heart disease. Even if you don’t have a specific gene for high cholesterol, genes still play a role in your cholesterol levels.
(ii) Dietary factors
Dietary factors that affect blood cholesterol include saturated fatty acids, unsaturated fatty acids, cholesterol and total calories. The formula for extrapolating blood cholesterol levels from dietary intake, summarized from the results of laboratory studies, is
Blood cholesterol = 1.26(S-P) + 1.5(100C/E)
Where: S saturated fatty acids as a percentage of total calories
P polyunsaturated fatty acids as a percentage of total calories
C cholesterol (mg)
E total calories (calories/day)
The intake of saturated fatty acids and cholesterol is the main cause of elevated blood cholesterol, and both saturated fatty acids and cholesterol are mainly derived from animal foods.
(iii) Body weight
Overweight or obesity both increase the concentration of LDL cholesterol. Reducing body weight can reduce the concentration of LDL cholesterol and also reduce the concentration of triglycerides and increase HDL cholesterol.
(iv) Physical activity
Regular physical activity can reduce LDL cholesterol concentration and increase HDL cholesterol level.
(V) Age and gender
Total blood cholesterol levels increase with age. Before menopause, total cholesterol levels in women are usually lower than those in men of the same age, and after menopause LDL cholesterol gradually increases and HDL cholesterol decreases. Total cholesterol levels are higher in women than in men after age 50.
(F) Alcohol
Alcohol intake increases HDL cholesterol, but does not decrease LDL cholesterol. Excessive alcohol consumption can damage the liver and heart muscle, lead to high blood pressure, and raise triglyceride levels. For these reasons, alcohol consumption is not recommended as a preventive measure against heart disease.
(vii) Mental stress
Many studies have proven that prolonged mental stress can cause elevated blood cholesterol. On the other hand, some people tend to eat many high-fat foods to cope with stress, which is also an important factor in elevated blood cholesterol.
IV. Factors affecting blood cholesterol levels
Cholesterol levels in the body are not only related to diet, but also determined by our own cholesterol synthesis and metabolism ability. In fact, our own cholesterol synthesis is sufficient to meet our body’s needs and there is no need to consume more cholesterol. The main factors that cause elevated blood cholesterol are
(i) Genetic factors
The influence of human genes on blood cholesterol levels depends on the rate of cholesterol synthesis and removal. Approximately one in 500 people suffer from familial hypercholesterolemia, often with premature coronary heart disease. Even if you don’t have a specific gene for high cholesterol, genes still play a role in your cholesterol levels.
(ii) Dietary factors
Dietary factors that affect blood cholesterol include saturated fatty acids, unsaturated fatty acids, cholesterol and total calories. The formula for extrapolating blood cholesterol levels from dietary intake, summarized from the results of laboratory studies, is
Blood cholesterol = 1.26(S-P) + 1.5(100C/E)
Where: S saturated fatty acids as a percentage of total calories
P polyunsaturated fatty acids as a percentage of total calories
C cholesterol (mg)
E total calories (calories/day)
The intake of saturated fatty acids and cholesterol is the main cause of elevated blood cholesterol, and both saturated fatty acids and cholesterol are mainly derived from animal foods.
(iii) Body weight
Overweight or obesity both increase the concentration of LDL cholesterol. Reducing body weight can reduce the concentration of LDL cholesterol and also reduce the concentration of triglycerides and increase HDL cholesterol.
(iv) Physical activity
Regular physical activity can reduce LDL cholesterol concentration and increase HDL cholesterol level.
(V) Age and gender
Total blood cholesterol levels increase with age. Before menopause, total cholesterol levels in women are usually lower than those in men of the same age, and after menopause LDL cholesterol gradually increases and HDL cholesterol decreases. Total cholesterol levels are higher in women than in men after age 50.
(F) Alcohol
Alcohol intake increases HDL cholesterol, but does not decrease LDL cholesterol. Excessive alcohol consumption can damage the liver and heart muscle, lead to high blood pressure, and raise triglyceride levels. For these reasons, alcohol consumption is not recommended as a preventive measure against heart disease.
(vii) Mental stress
Many studies have proven that prolonged mental stress can cause elevated blood cholesterol. On the other hand, some people tend to eat many high-fat foods to cope with stress, which is also an important factor in elevated blood cholesterol.