If there is too much cholesterol in the body, it can build up in arteries, leading to coronary heart disease (CHD) and many other serious conditions (e.g. stroke).
Cholesterol is made up of two kinds of cholesterol- LDL and HDL cholesterol.
LDL cholesterol is called "bad" cholesterol as elevated levels of LDL cholesterol are associated with an increased risk of coronary heart disease. LDL lipoprotein deposits cholesterol on the artery walls, causing the formation of a hard, thick substance called cholesterol plaque. Over time, cholesterol plaque causes thickening of the artery walls and narrowing of the arteries, a process called atherosclerosis.
However, research suggests there are two types of LDL particles.
Large fluffy particles (Type A) which are believed to be harmless and small dense particles (Type B), that are damaging and harmful to arterial walls.
HDL cholesterol is called the "good cholesterol" as HDL cholesterol particles prevent atherosclerosis by extracting cholesterol from the artery walls and disposing of them through the liver.
High levels of LDL cholesterol and low levels of HDL cholesterol are risk factors for atherosclerosis, while low levels of LDL cholesterol and high levels of HDL cholesterol are desirable.
However, it is also important to know the type of LDL particles you have. Lots of Type A particles are good but if you have lots of Type B particles, even if your LDL levels are low, this could be causing arterial damage.
Cholesterol levels in the blood depend on both dietary factors and the amount of cholesterol manufactured by the body. Genetics also play a role in some people with high cholesterol. Your genes will partly determine how much cholesterol you naturally produce. Familial hypercholesterolemia is more likely to be present in people who experience a heart attack at an early age or who have a family member who had a heart attack at an early age.
Being overweight contributes to increased LDL-cholesterol.
Other blood markers that may be associated with high cholesterol levels and are also risk factors for cardiovascular disease include high levels of a compound called homocysteine and high blood levels of triglycerides (fats).
Triglycerides - are the main form of fat stores in the body. They act as an energy reserve and provide a protective layer for delicate organs.
Knowing your cholesterol levels
The only way to find out your cholesterol level is to have a blood test. Cholesterol is measured in units called millimoles per litre of blood, usually shortened to mmol/litre or mmol/L and your doctor can arrange for you to get it tested.
A Total Cholesterol Test is the sum of LDL (low density) cholesterol, HDL (high density) cholesterol, VLDL (very low density) cholesterol, and IDL (intermediate density) cholesterol. It is given as one single number.
When having cholesterol tests performed it is not just the total cholesterol that is important. It is the breakdown of markers including LDL, HDL, Triglycerides, Type A/B, arterial stiffness and calcium scores, that will give you a far more comprehensive analysis of your arterial health.
What is the recommended cholesterol level?
The recommended cholesterol level for the general public is below 5.5mmol/L. For people at higher risk of heart problems, the Heart Foundation recommends a cholesterol level of less than 4.0mmol/L.
“Normal” cholesterol levels
- Total Cholesterol – 3.9-5.5 mmol/l
- HDL Cholesterol (male) – 0.9-2.0 mmol/l
- HDL Cholesterol (female) – 1.0-2.2 mmol/l
- LDL Cholesterol – 2.0 -3.4 mmol/l
- Triglycerides: < 1.7 mmol/L