Cholesterol is a type of fat (lipid) that is found in your blood. Cholesterol is important as high levels in your blood can lead to narrowing and blockage of arteries and this increases your risk of developing coronary heart disease (CHD) one of the commonest causes of death and disability in Europe, North America and Australia. CHD usually results from abnormalities that narrow the arteries supplying blood to your heart the coronary arteries, hence the name coronary heart disease . Narrowing of these arteries may restrict or completely block the supply of blood to your heart muscle. This process can also occur in other parts of your circulation.