Cholesterol ('hard bile') is the main component of the body's cell wall. 80% of cholesterol is produced in the liver, the remaining 20% comes from food. Thanks to it the cell wall is not destroyed by various aggressive factors. Another important function is participation in production of various biologically active substances - vitamin D, steroid hormones of adrenal glands, female hormones (estrogen, progesterone), testosterone. It also helps in the transmission of signals from one nerve cell to another.

The main purpose of the total cholesterol test is to diagnose atherosclerosis (and, as a consequence, coronary heart disease - CHD).

There are three types of cholesterol - high density lipoproteins (HDL), low density lipoproteins (LDL) and very low density lipoproteins (VLDL). HDL and LDL are clinically important because of their characteristics.

High-density lipoproteins (HDL)

The "healthy" fraction of cholesterol. There is an inverse correlation between HDL and CHD - the higher the HDL, the lower the risk of developing heart disease. Every 0.13 mmol/l (5mg/dl) decrease in HDL concentration leads to a 25% increase in the risk of CHD!

High HDL values are positively evaluated as an anti-atherogenic factor.

Knowing the amounts of total cholesterol and HDL, an atherogenicity coefficient (Ca) can be calculated:

Ca = Total CL - HDL/HDL

Patients with CHD have a ratio greater than 4.

There are a number of diseases that alter HDL levels in the blood

Increase: primary biliary cirrhosis, hepatitis, alcoholism.

Decrease: diabetes, kidney and liver diseases, acute bacterial or viral diseases.

Low-density lipoproteins (LDL)

"Harmful" cholesterol. Their negative function is as follows: the wall of blood vessels has a mesh structure. LDL penetrates these cells and gets "stuck", while HDL pass through the vascular structure and are not trapped in any way. Then, in place of the "stuck cell", inflammation occurs and an atherosclerotic plaque begins to form.

The higher the level of LDL in the blood, the greater the risk of coronary heart disease. A concentration of more than 4.14 mmol/l is considered a very high risk of developing atherosclerosis and CHD.

Read also: "the truth about cholesterol and lipids"