General Info |
Cholesterol is a type of fat, one which is very important for life. It is a vital building block of many substances including the cell membrane of every cell in our body. The word 'cholesterol' is associated with heart disease and obesity. However cholesterol is a very important type of fat for vital living.
We have to have some cholesterol, but the liver can make as much as we need. If the level is too high, it can be deposited in tissues, specifically the arteries, causing them to narrow and not carry enough blood to vital organs such as the brain or the heart. It can also weaken the artery, causing it to enlarge and produce an aneurysm. This process is termed "arteriosclerosis".
The cholesterol in a person’s blood originates from two major sources, dietary intake and liver production. Dietary cholesterol comes mainly from meat, poultry, fish, and dairy products. Organ meats, such as liver, are especially high in cholesterol content, while foods of plant origin contain no cholesterol. After a meal, cholesterol is absorbed by the intestines into the blood circulation and is then packaged inside a protein coat. This cholesterol-protein coat complex is called a chylomicron. |
Causes
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*Hyperlipidemia is caused by excess lipids or fatty substances in the blood and is
an important risk factor in developing atherosclerosis and heart disease. |
*Genetic factors, as in certain hereditary diseases like diabetes can also lead to
the development of this condition. |
*Mental stress, physical activity and change in body weight can also influence the
level of blood cholesterol. |
*Inactivity can increase it and exercise can decrease it. |
LDLs, HDLs and your heart |
Cholesterol is carried in the blood as a package called lipoproteins. Like oil and water, cholesterol and blood do not mix. So, in order to be able to pass through the bloodstream, the cholesterol made in the liver is also smeared with a layer of protein making a lipoprotein. This lipoprotein then carries the cholesterol through the bloodstream. The density of Lipoproteins varies and they are classified according to the density as Low density lipoproteins (LDL) and High Density Lipoproteins (HDL). As the density differs, the action of both differs. |
Low-density lipoproteins (LDLs) carry most of the cholesterol in the blood and are also known as 'bad cholesterol'. The cholesterol and fat from LDLs are the main source of cholesterol accumulation and blockage in the arteries. Thus, the more LDL-cholesterol is there in the blood, the greater the risk of heart disease. |
High-density lipoproteins (HDLs) or the good cholesterol carry some of the cholesterol in the blood, but this cholesterol goes back to the liver, which leads to its removal from the body. So HDLs help prevent cholesterol from building up in the walls of the arteries. If the level of good cholesterol is low, the risk of heart disease is greater. |
How does high blood cholesterol lead to heart disease? |
The excess cholesterol in your blood can become attached to the walls of arteries. This attached cholesterol gradually causes hardening of the arteries by forming what are known as ' plaques'. The narrowed inside of arteries will disrupt or stop normal blood circulation to heart or other vital organs like brain or kidneys. This condition is called atherosclerosis. Thus the organ gets less oxygen than it needs. When this accumulation happens in the arteries of the heart it cuts down the blood supply to the heart muscles that is working non-stop. The muscle starved of blood is starved of oxygen and nutrition such as glucose. This leads to chest pain or angina. A sluggish blood flow in an artery is more prone to form a clot and if this happens a complete cut off of the blood supply leads to the death or infarction of the chest muscle: A heart attack ot MI results. The whole process of cholesterol accumulation is slow and happens over the years without making the person aware of what is happening, unless there is a regular check up. |
What are the Risk Factors? |
*Diabetes mellitus. |
*Dietary fat intake. |
*Excessive use of alcohol and smoking. |
*Obesity. |
*Hypothyroidism - a low level of thyroid hormone |
*Certain kinds of renal failure. |
*Drug risk factors like birth control pills, hormones such as estrogen and
corticosteroids. |
Symptoms
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*A strong family history of early myocardial infarction (heart attack). |
*Elevated and therapy-resistant levels of LDL in either or both parents. |
*Xanthomas (lesions caused by cholesterol deposits). |
*Cholesterol deposits in the eyelids (xanthelasmas). |
*Chest pain (angina) associated with coronary artery disease. |
*Evidence of obesity. |
Diagnosis
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*Physical examination and laboratory tests are done to identify secondary causes
of hyperlipidemia or familial disorders, if lipoprotein levels are high. |
*Blood cholesterol tests. |
Treatment
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The goal of treatment is to reduce the risk of atherosclerotic heart disease and resulting myocardial infarction (heart attack). |
Diet modification is the initial phase of treatment and is tried for several months before drug therapy is added. Diet modifications include reducing total fat intake to 30% of the total calories consumed. Saturated fat intake is reduced by decreasing the amounts of beef, pork, and lamb; substituting low-fat dairy products; and eliminating coconut and palm oil. Cholesterol intake is reduced by eliminating egg yolks and organ meats. Further reductions in the percentage of fat in the diet may be recommended after the initial trial period. Dietary counseling is often recommended to assist people with these adjustments to their eating habits. |
Exercise, especially to induce weight loss, may also aid in lowering cholesterol levels. |
Drug therapy may be initiated if diet, exercise, and weight reduction efforts have not reduced the cholesterol levels after an adequate trial period. |
More Info
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