Le cholesterol is a fat body essential for the functioning of the organism. It is used in particular in the composition of cell membranes and serves, among other things, as a “raw material” for the synthesis of numerous hormones (steroids).

However, excess cholesterol can be harmful as it tends to build up in the blood vessels and to form so-called platesatherosclerosis which can ultimately increase cardiovascular risk.

Cholesterol is not soluble in the blood: it must therefore be transported there by proteins, with which it forms complexes called lipoproteins.

Cholesterol can be associated with several types of “carriers” in the blood:

• of the LDL (For low-density lipoproteins): LDL-cholesterol is considered the “bad” cholesterol. The reason ? LDL carries cholesterol from the liver to the rest of the body. If LDL-cholesterol is present in too large amounts, it is associated with an increased cardiovascular risk.
• of the HDL (For high-density lipoproteins): HDL cholesterol is often referred to as the “good” cholesterol. This is because HDL’s function is to “pump” cholesterol from the blood and transport it to the liver, where it is stored. They therefore have the effect of lowering the level of cholesterol in the blood, and a high level of HDL is associated with a lower cardiovascular risk.
• of the VLDL (For very low-density lipoproteins): they mainly contribute to transporting another type of fat, triglycerides.

Blood cholesterol comes from food but also from so-called endogenous synthesis, in the liver.

Blood cholesterol level measurement (cholesterolemia) is done routinely, especially after 40 years (or 35 years for men and 45 years for women), with the aim of detecting hypercholesterolemia and make a ” lipid profile “. This assessment must be carried out once every 5 years minimum after this age.

The measurement can also be indicated, among others:

• before prescribing contraception
• in a person on cholesterol-lowering treatment, to check the effectiveness of the treatment
• if you have symptoms suggesting high cholesterol (skin lumps called xanthomas).

The cholesterol analysis will take stock of the total cholesterol level, but also on the LDL-cholesterol,  HDL-cholesterol and the total cholesterol / HDL ratio, which helps assess cardiovascular risk. At the same time, a blood triglyceride measurement is taken.

The cholesterol is determined by blood test in a medical analysis laboratory.

The doctor will give you instructions on the need to be fasting or not, not to drink alcohol before the test and to take (or not) your medicines, if you are under treatment.

Depending on the result, the doctor may decide whether or not to initiate a treatment called ” hypolipémiant ” or ” hypocholestérolémiant », In order to lower the level of fat in the blood, if it is too high. We distinguish :

• pure hypercholesterolemia: elevated LDL-cholesterol levels.
• Pure hypertriglyceridemia: high triglyceride level (≥ 5 mmol / l).
• Mixed hyperlipidemia: elevated LDL-cholesterol and triglyceride levels.

The balance sheet is considered normal if:

• LDL-cholesterol <1,60 g / l (4,1 mmol / l),
• HDL-cholesterol> 0,40 g / l (1 mmol / l),
• triglycerides <1,50 g / l (1,7 mmol / l).

However, treatment recommendations depend on the patient’s age and other cardiovascular risk factors. They also vary slightly from country to country.

In general, treatment (dietetic and / or drug management) is started when the LDL-cholesterol is greater than 1,6 g / l (4,1 mmol / l) but when the combined cardiovascular risk is very high (hypertension , diabetes, cardiovascular history, etc.), treatment can be started if the LDL-cholesterol level is greater than 1 g / l.