Cholesterol is a lipid from the sterol family found in animal products. The liver produces most of the cholesterol that the body needs to function. The rest of the “necessary” cholesterol is provided by the diet. Cholesterol is a constituent of cell membranes and the precursor of sex hormones (progesterone, estrogen, testosterone), billiary salts and vitamin D3. 

Cholesterol is not soluble in the blood. It is thanks to the lipoproteins that it will be transported and conveyed throughout the body. There are 2 types of lipoproteins:

• LDL lipoproteins (low density lipoproteins) associated with ” Wrong » cholesterol which deposit the cholesterol present in excess in the body on the walls of the arteries and which cause, in the long term, atherosclerosis, that is to say the presence of a plaque on the internal wall of the arteries which can interfere or block the flow of blood.
• HDL lipoproteins (high density lipoproteins) associated with ” Well » cholesterol pick up the cholesterol deposited on the artery walls by the LDL lipoproteins and eliminate them.

It is therefore the lipoproteins that define the levels of “good” and “bad” cholesterol present in the blood. Cholesterol is neither “good” nor “bad” per se, but its carriers (lipoproteins) are “good” or “bad”. 

How to detect hypercholesterolemia?

By a blood test which will determine the cholesterol levels (the amount of LDL cholesterol, the amount of HDL cholesterol and the total amount of cholesterol) and by an analysis of these results.

Doctors evaluate the cholesterol level in a relative way, that is to say by analyzing these levels in relation to the general condition of the patient and the presence of other factors such as personal history of cardiovascular disease, age, smoking, diabetes, high blood pressure, family history of cardiovascular disease, obesity and gender.

Doctors also analyze the total cholesterol / HDL cholesterol ratio, which shows the level of “good” cholesterol in the blood compared to total cholesterol. A low ratio is linked to a lower risk of disease. 

For example, at equal cholesterol levels, a 60 year old man who smokes and has a history of cardiovascular disease in his family will be considered high risk while a 30 year old woman without risk factors will be considered low risk. . 

http://www.statcan.gc.ca/pub/82-625-x/2010001/article/11136-fra.htm http://www.mangerbouger.fr/IMG/pdf/PNNS_2011-2015.pdf