Cholesterol and atherosclerosis

Cholesterol is a steroid compound which forms with the breakdown of the fat in our body. Since cholesterol takes part in the formation of the bile acid, sex hormones and hormones of the adrenal gland, it is essential for the normal functioning of the body.

Cholesterol is carried in the blood by proteins in the plasma, building a biochemical complex called lipoprotein.

There are two types of lipoproteins:

• low-density lipoprotein i.e. “bad” cholesterol (LDL), lipoproteins which carry high concentration of cholesterol; and

• „good“cholesterol (HDL) – lipoproteins which carry low concentration of cholesterol.

LDL carries cholesterol in the blood vessels, forming an atheromatous plaques within the arteries that cause narrowing of the lumen of the blood vessels, thus leading to heart, brain and other diseases.

HDL, in turn, improves the elasticity of the blood vessels, hence its deficiency in the body makes blood vessels non-elastic and stiff. Almost two-thirds of the cholesterol is synthesized in the liver (800-900 mg) and only 1/3 is directly ingested through food.

Atherosclerosis

Atherosclerosis is a process of accumulation of fat on the inner walls of large and medium-sized arteries. At the beginning, they are small crystals of cholesterol, which gradually create deposits (plaque) that narrow the lumen of the blood vessel. Subsequently, scarring and hardening of the wall of blood vessels occurs, making them more prone to rupture. These changes of the inside of the blood vessel lead to blood clots or lead to a condition known as thrombosis.

There are several causes of atherosclerosis, but increased concentration of cholesterol in the form of low density lipoprotein (LDL) is the most common one. Factors leading to an increased risk of developing atherosclerosis fall into two groups: – Modifying factors- smoking, physical activity, diet, etc.- Non-modifying factors– gender, age, genetic factors -Other factors – diabetes, obesity, elevated levels of LDL, homocysteine, triglycerides, uric acid and other substances in the blood, hyperthyroidism, and other conditions.

What is considered a high blood cholesterol level?

For healthy people, with no family history of heart disease, the level of total cholesterol in the blood should not be higher than 5.2 mmol/l, whereas HDL should be higher than 1 mmol/l and LDL less than 3 mmol/l. Any cholesterol level over these reference values (especially LDL cholesterol) increases the risk of heart disease.

Do men and women have the same risk of high cholesterol?

Can increased levels of cholesterol cause a heart attack? The increased level of cholesterol is the most common cause of heart attack. On its own, increased cholesterol levels do not cause symptoms, but it is the major risk factor for atherosclerosis, which in turn can cause a heart attack. Therefore, in people with heart disease, the level of LDL cholesterol in the blood must not exceed 2.5 mmol/l.

Is increased body weight always a sign of increased level of cholesterol in the blood?

The increased level of cholesterol in the blood is not always related to increased body weight. It is a big misconception that only people with increased body weight have increased cholesterol in the blood. Many people have high cholesterol as a result of genetic-hereditary predisposition, although they might have normal weight or even be thin. However, most people with increased body weight have higher levels of cholesterol. About half of the patients have elevated blood cholesterol levels as a result of inadequate diet, and in the other half, the cause is their genetic predisposition. All products of animal origin: eggs (yolk), liver, brain, butter, sour cream, red meat, cured meat products, and semi fat cheeses contain saturated fatty acids, which increase the level of LDL cholesterol in the blood. Therefore, a healthy diet with fresh fruits and vegetables, regular physical activity, terminating the smoking habit, and stress reduction are essential factors in maintaining normal levels of blood cholesterol.