Cholesterol is one of the body's fats (lipids). Cholesterol and another lipid, triglyceride, are important building blocks in the structure of cells and are also used in making hormones and producing energy. To some extent, the cholesterol level in blood depends on what you eat but it is mainly dependent on how the body makes cholesterol in the liver. The "Qi" level in your Liver and Kidneys.

Having too much cholesterol in the blood is not a disease in itself, but can lead to the hardening and narrowing of the arteries (atherosclerosis) in the major vascular systems.

For the sake of simplicity, there are two sorts of cholesterol: a 'good' sort called high density lipoprotein (HDL) and a 'bad' sort called low density lipoprotein (LDL).

HDL has a useful effect in reducing tissue cholesterol and taking it back to the liver. HDL actually protects against atherosclerosis. LDL may contribute to diseases of the arteries (cardiovascular disease).

The proportion of LDL-cholesterol to HDL-cholesterol that influences the degree to which atherosclerosis is likely to cause problems (heart attack).

LDL-cholesterol level can be lowered by eating a low fat diet. HDL-cholesterol level can be raised by exercising.

The significance of any particular cholesterol level cannot be assessed without taking into account the ratio between good and bad cholesterol (either total-cholesterol/HDL-cholesterol ratio or LDL-cholesterol/HDL cholesterol ratio) or the presence of other cardiovascular risks, such as smoking, diabetes and high blood pressure (hypertension). It is possible for someone to have a high level of total cholesterol and still have a relatively low cardiovascular risk because of an absence of other risk factors or because their family history is free from coronary disease.

Anyone with an established track record of cardiovascular disease such as angina pectoris, a previous myocardial infarction, coronary angioplasty or coronary bypass surgery should seek advice to keep their total Cholesterol level below 5.2mmol/l or their LDL below 3.2mmol/l.

Cholesterol levels can run in families. If the inherited cholesterol levels are very high, this is called familial hypercholesterolemia (FH) or familial combined hyperlipidaemia (FCH) where the triglyceride levels are very high as well. Levels can also be influenced by the part of the world you live in: cholesterol levels in northern European countries are higher than in southern Europe and much higher than in Asia. It is known that the relationship to food is significant, but there is no doubt that genes also play a part. High cholesterol is also seen in connection with other diseases, such as reduced metabolism (due to thyroid hormone problems, for example), kidney diseases, diabetes and alcoholic's.

High level of cholesterol in conjunction with other adverse factors increases the risk of developing atherosclerosis and cardiovascular disease.

Atherosclerosis resulting in narrowing of the arteries. This does not occur suddenly, but builds up over many years during which cholesterol and fat have been deposited in the artery walls. The result is that the arteries become constricted and hardened, their elasticity disappears and the volume of blood able to travel through them is reduced.

The symptoms are therefore the consequences of cardiovascular disease. They depend on the degree of narrowing, may cause ruptures , and also the organ supplied by the affected arteries.

In the brain, an atherosclerotic carotid or cerebral (brain) artery might block with clotted blood (thrombus) or a smaller intracerebral vessel may rupture causing a local hemorrhage. Both these circumstances result in a stroke (Choong Fung).

In the heart, narrowed coronary arteries cause angina, and ruptured plaques cause Coronary Thrombosis (myocardial infarct), which may lead to reduced heart function (heart failure) if a significant amount of heart muscle is damaged. The obstruction of "Qi" in the Heart.

Carotid arteries in the neck can become narrowed and may lead to clots forming in the neck and floating downstream into the brain, causing a stroke (CVA) or recurrent temporary strokes (transient ischemic attacks, also known as TIAs).

Leg pain on exertion can be experienced due to atherosclerosis in the arteries that supply the lower limbs (intermittent claudicating). If a major peripheral vessel to a lower limb blocks suddenly, an acutely ischemic leg will occur which may be limb-threatening. In the worst cases of chronic lower limb atherosclerosis, this can lead to a leg so starved of blood that it cannot survive and requires amputation.

Commonly for some people affected to have the disease in several arteries throughout their circulation including the aorta (the main artery in the chest and abdomen, the renal (kidney) arteries and the mesenteric (intestinal) vessels.

Familial hypercholesterolemia is - raised cholesterol levels in the blood - hypercholesterolemia - are generally caused by a poor diet and lifestyle in combination with the way an individual produces cholesterol in their liver.

In some individuals (1 in 500 of the population), the high cholesterol level in the blood is caused by a specific genetic defect. People with inherited or familial hypercholesterolemia (FH) are lacking in the low-density lipoprotein (LDL) receptors that remove cholesterol from the bloodstream.

Raised cholesterol level in the blood is present from birth and it leads to an early development of atherosclerosis and vascular diseases. The disease is transmitted from generation to generation in such a way that children of a person with FH have a 50 percent risk of getting FH. The disease does not skip generations which means that children and grandchildren of family members who do not have a defective gene are therefore not at risk from FH.

People with FH -Familial hypercholesterolemia cannot feel that they have a raised cholesterol level, but they might have symptoms of cardiovascular disease, which develops as a result of the narrowing of the arteries.

The symptoms can include:
pressing, crushing pain behind the breastbone, possibly radiating to the arm or to the neck, associated with physical exertion or cold (angina pectoris).
if the symptoms become more severe and sustained it may be a sign of an acute Coronary Thrombosis (heart attack).
The development of atherosclerosis begins in childhood and can be compared to calcium deposits in a water pipe. Gradually, the opening gets smaller and smaller, the inner surface becomes more irregular, the blood can no longer flow freely, leading to symptoms.

When the blood supply to the tissue stops, the tissue dies. This means that if a blood clot is situated in one of the vessels of the heart (the coronary arteries), the area of the heart muscle supplied by that vessel is injured irreversibly. Scar tissue forms and the heart is left weakened.

Why do you get raised cholesterol? Hereditary, food and environmental factors affect the cholesterol level. Today we know of several hereditary disorders that cause significantly raised LDL-cholesterol.

The cholesterol level in northern European countries is higher than in southern Europe and much higher than in Asia. We know that diet is a major factor but there is no doubt that genes also play a part.

Raised blood cholesterol can also be a feature of the following diseases:
- hypothyroidism (under active thyroid gland)
- kidney diseases
- diabetes
- alcohol abuse.

The progress of FH -Familial hypercholesterolemia varies greatly. However, in a particular family it tends to follow a similar pattern.

The risk of a fatal heart attack before the age of 40 is significantly higher in those with FH than among the general population.

Research shows that 50 percent of men and 40 percent of women with FH have had a blood clot in the coronary arteries before the age of 60.

About one third of patients with FH show no symptoms until sudden cardiac death.