What is cholesterol?

Cholesterol is a waxy, fat-like substance found in all cells of the body. It helps to digest fats, make hormones and strengthen cell walls. If levels become too high, cholesterol can build up on artery walls causing the arteries to narrow and restricting the flow of blood to the heart. This can increase the risk of cardiovascular disease (disease affecting the heart and blood vessels).

Cholesterol is carried in the blood by substances called lipoproteins. Low-density lipoprotein (LDL) is the main cholesterol carrier in the blood and is sometimes referred to as "bad" cholesterol. It can combine with other substances to form hard deposits known as plaques on artery walls. A high level of LDL cholesterol can increase the risk of cardiovascular disease.

High-density lipoprotein (HDL) carries only a small proportion of cholesterol. It carries cholesterol away from the arteries and back to the liver where it is broken down. For this reason it is often referred to as "good" cholesterol. A high level of HDL cholesterol can protect against cardiovascular disease and a low level indicates a greater risk of cardiovascular disease.

What causes a high cholesterol level?

A high level is usually caused by a combination of diet and a genetic tendency, ie, it can run in families. Men tend to have higher levels of LDL cholesterol than women, although after the menopause the difference between men and women disappears. There are several things you can do to help to decrease your cholesterol levels - these are outlined in the self-help section.

Are there any tests necessary?

A simple blood test can measure blood cholesterol levels. This test should be done for anyone with a strong family history of cardiovascular disease or anyone with existing cardiovascular disease or circulatory problems. It should also be done for people with other risk factors for cardiovascular disease such as diabetes, high blood pressure and smoking. The test will measure levels of total cholesterol, HDL cholesterol and non-LDL cholesterol.

What treatment is available?

If your cholesterol levels are raised your doctor will advise you about changes you can make to your diet and lifestyle that may help to reduce your cholesterol levels. Your doctor will also want to start drug treatment to reduce your risk of having a cardiovascular disease event (eg, a heart attack).

The goal of treatment is to reduce your non-HDL cholesterol level by more than or equal to 40%. Research suggests that patients with diabetes who have a cholesterol level in the normal range may still benefit from treatment with a cholesterol lowering drug. The same applies to people with other risk factors for cardiovascular disease.

There are a number of different drug treatments that can be prescribed to reduce cholesterol levels:

Statins decrease blood cholesterol. These include atorvastatin (eg, Lipitor®), fluvastatin (eg, Lescol®, Lescol® XL, Luvinsta® XL), pravastatin, rosuvastatin (Crestor®) and simvastatin (eg, Zocor®).

Fibrates are used to reduce raised cholesterol and triglyceride levels in the blood. They are most effective against raised triglycerides. These include bezafibrate (eg, Bezalip®, Bezalip® Mono), ciprofibrate, fenofibrate (eg, Lipantil® Micro, Supralip®) and gemfibrozil (eg, Lopid®).

Cholib® is a tablet containing both a statin (simvastatin) and a fibrate (fenofibrate). It is used to reduce raised triglycerides and increase HDL cholesterol when LDL cholesterol levels are already controlled with simvastatin treatment.

Ezetimibe (Ezetrol®) is a cholesterol absorption inhibitor that decreases the absorption of cholesterol from the intestine. In many cases it will be given in combination with a statin. A combination product containing ezetimibe and simvastatin is also available (Inegy®).

Bile-acid sequestrants decrease blood cholesterol and increase the breakdown of LDL cholesterol. These include colesevelam (Cholestagel®), colestipol (Colestid®) and colestyramine (eg, Questran® Light).

Alirocumab (Praluent®) and evolocumab (Repatha®) are from a different class of treatments that increase the breakdown of LDL cholesterol and may be used when statins are not suitable. Both treatments come as a pre-filled pen that you may be able to inject yourself with after your doctor has shown you how to do this.

Other treatments that may be prescribed include acipimox (Olbetam®), a nicotinic acid derivative, which lowers both triglyceride and cholesterol levels and increases HDL-cholesterol.

Fish oils can reduce very low density lipoprotein (VLDL) cholesterol in the liver. Capsules containing fish oils are available. However, adding oily fish (eg, sardines, mackerel, salmon) to the diet may be more beneficial than taking supplements.

Self-help measures

  • If you are overweight aim to reduce all the fats in your diet. If you are not overweight, aim to reduce the amount of saturated fat that you eat. A blood cholesterol lowering diet is the most important factor in reducing blood cholesterol levels:

    - Consume at least 5 portions of fresh fruit and vegetables every day, eat more high-fibre cereals and bread - foods from plants (fruit, vegetables, grains and seeds) do not contain cholesterol.
    - Dairy foods: use skimmed or semi-skimmed milk. Eat low-fat cheeses and yoghurts. Use low-fat spreads instead of butter or margarine.
    - Meat: eat smaller portions, trim off any fat. Grill or bake rather than frying.
    - Processed foods (eg, sausages, beef burgers, meat pies): eat these only occasionally. Foods such as crisps, biscuits, cakes, pastry and nuts are also high in hidden fats.
  • Take regular exercise - exercise is important in controlling cholesterol levels. Total and LDL cholesterol levels tend to decrease with activity while levels of HDL cholesterol increase. Aerobic activity, eg, walking, running, swimming, cycling and dancing, is best. Exercise can also help to control weight, high blood pressure and diabetes, which are all risk factors for heart disease.
  • If you smoke, try to give up - smoking raises LDL cholesterol. It also raises blood pressure and constricts blood vessels.
  • Limit your alcohol limit to less than 14 units per week (spread over three or more days) with two or more drink-free days each week (1 unit = 1/2 pint beer/cider; 1/2 glass wine [76mL]; 1 pub measure of spirits [25mL])
  • Reduce your salt intake to less than 6g per day

Further information available from:

British Heart Foundation
Greater London House
180 Hampstead Road
London NW1 7AW
Tel: 020 7554 0000
Heart Help Line:
 - 0300 330 3311 (Monday to Friday, 9am-5pm)

Heart UK
7 North Road
Berkshire SL6 1PE
Tel: 01628 777046
Helpline: 0345 450 5988 (Monday to Friday, 10am-3pm)

Fact sheet provided by MIMS

Date last reviewed: September 2016

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