Cholesterol is a substance essential for normal functioning of the human body. It is a fatty compound and most of it is produced in the liver; however, it is also contained in food.
Increased level of cholesterol and other lipids does not cause any immediate symptoms but it is a strong risk factors for cardiovascular diseases including heart attack and stroke.
Types of cholesterol
Cholesterol (type of lipid) circulates in blood bound to proteins in lipoprotein complexes. Some of the lipoproteins have protective effect, others are harmful.
- High-density lipoprotein (HDL): HDL takes cholesterol away from the cells towards the liver where it is broken down or removed from the body as waste material. That is why it is called 'good cholesterol' and a high level of HDL cholesterol is beneficial for health.
- Low-density lipoprotein (LDL): LDL takes the cholesterol from liver towards cells that need it. If the body can’t use up all LDL cholesterol, the excess builds up in the wall of arteries, creates plaques that can cause problems. LDL is therefore 'bad cholesterol' and a high level is bad for health.
Blood tests are available to assess either level of total cholesterol in blood (the lower the better) or for lipid profile which usually includes total cholesterol, HDL cholesterol (high is good), LDL cholesterol (low is good), total cholesterol/HDL ratio (low is good) and triglycerides (low is good). Cholesterol level varies among healthy persons as well as among those who are at higher risk.
Consequences of high cholesterol?
High level of cholesterol may cause:
- Angina and heart attack
- Mini stroke (transient ischaemic attack, TIA) and stroke
- Peripheral vascular disease (narrowings of the arteries in the legs)
Cholesterol deposits in the arteries restrict the blood flow to brain, heart and rest of the body. The cholesterol plaques also increase risk of blood clots leading to a sudden occlusion of an artery which in brain would cause stroke and in heart a heart attack.
Causes of high cholesterol
- Unhealthy diet - dietary cholesterol and saturated fats in the food obviously increase the level of cholesterol in blood.
- Smoking - some substances in cigarettes may block the transportation of LDL from cells to liver, increasing its level in the arteries leading to the narrowing of the arteries.
- Familial hypercholesterolaemia – a rare genetic condition which lead to very high cholesterol levels regardless of eating habits.
Who should have their cholesterol checked?
Lipid profile or at least total cholesterol should be checked in people with:
- Age over 40 years
- Established coronary artery disease (CAD), peripheral vascular disease (PVD) and mini stroke (TIA) or stroke
- Family history of premature heart disease
- Diabetes, hypertension or underactive thyroid
- Unhealthy weight and obesity
- Familial hypercholesterolaemia
How to reduce cholesterol levels?
Healthy and balanced diet with wholegrain cereals, fruit and vegetables is the first step to lower the cholesterol level.
Quit smoking, reduce alcohol consumption to recommended limits and do regular exercise.
If the lifestyle changes are not sufficient, your GP or consultant may prescribe drugs called statins (e.g. simvastatin, atorvastatin, rosuvastatin) to reduce your cholesterol level.