What is Cholesterol? Facts about Cholesterol.
Cholesterol is a fatty organic molecule, produced by the liver. This waxy, fat-like substance has several important functions into the human body:
- It is a structural component of the cell membranes (outer layer); it determines which molecules can pass into the cell and which cannot (cell membrane permeability).
- It is essential for the production of some hormones, such as cortisol, corticosterone, aldosterone, and sex hormones (androgens and estrogens).
- It insulates nerve fibers.
- It aids in the production of bile and of vitamin D.
- It helps the body to metabolize fat soluble vitamins like A, D, E, and K.
Cholesterol is carried in the blood by molecules called lipoproteins. A lipoprotein is any complex or compound containing both lipid (fat) and protein. There are three main types of lipoprotein:
- LDL (low density lipoprotein)- bad cholesterol. LDL carries cholesterol from the liver to cells. If the LDL levels are too high, the excess of LDL is build up and the risk of arterial disease increases. Most human blood contains approximately 70% LDL.
- HDL (high density lipoprotein)- good cholesterol. HDL takes the cholesterol away from the cells and back to the liver. In the liver it is either broken down or expelled from the body as waste. Experts say HDL prevents arterial disease.
- Triglycerides – Most fat exists in the body, as well as in food as triglycerides. In the human body, calories which are not used immediately by our tissues are converted into triglycerides and stored in fat cells. While in the blood, triglycerides, in association with cholesterol, form the plasma lipids (blood fat)..
The amount of cholesterol in human blood can vary from 3.6 mmol/liter to 7.8 mmol/liter. The values over 6 mmol/liter are high. The desirable cholesterol level is under 5 mmol/liter.
High cholesterol levels can cause:
- Atherosclerosis – narrowing of the arteries.
- Higher coronary heart disease risk – an abnormality of the arteries that supply blood and oxygen to the heart.
- Heart attack – occurs when the supply of blood and oxygen to an area of heart muscle is blocked, usually by a clot in a coronary artery
- Angina – chest pain or discomfort that occurs when your heart muscle does not get enough blood.
- Other diseases of the heart and blood vessels.
- Stroke and mini-stroke – occurs when a blood clot blocks an artery or vein, interrupting the flow to an area of the brain. Can also occur when a blood vessel breaks. Brain cells begin to die.
High cholesterol can be caused by:
- The foods we eat. Eating too much saturated fat, trans fat, and cholesterol can cause high cholesterol. Saturated fat and cholesterol are in foods that come from animals, such as meats, whole milk, egg yolks, butter, and cheese. Trans fat is found in fried foods and packaged foods, such as cookies, crackers, and chips.
- Being overweight may increase triglycerides and decrease HDL (good cholesterol).
- Lack of physical activity can lower HDL.
- Age and gender influence the cholesterol levels – the older, the higher the levels of cholesterol.
- Certain diseases like hypothyroidism, chronic kidney disease, and other kidney problems may raise the risk of high cholesterol.
- Usually the high cholesterol levels are inherited from the family.
- Cigarette smoking can lower your HDL cholesterol.
- Some medicine, such as thiazide diuretics, beta-blockers, estrogen, and corticosteroids, can raise triglyceride levels and lower HDL (good) cholesterol levels.