Cholesterol is a waxy steroid and is transported in the blood plasma of all animals. It is the main sterol synthesized by animals - small amounts are also synthesized in plants and fungi. A sterol is a steroid sub-group. Cholesterol levels among US adults today are generally higher than in all other industrial nations. During the 1990s there was some concern about cholesterol levels in American children. According to the CDC (Centers for Disease Control and Prevention), nearly 1 in every 10 children/adolescents in the USA has elevated total cholesterol levels; and this was after concentrations had dropped over a 20-year period.
-It builds and maintains cell membranes (outer layer), it prevents crystallization of hydrocarbons in the membrane
-It is essential for determining which molecules can pass into the cell and which cannot (cell membrane permeability)
-It is involved in the production of sex hormones (androgens and estrogens)
-It is essential for the production of hormones released by the adrenal glands (cortisol, corticosterone, aldosterone, and others)
-It aids in the production of bile
-It converts sunshine to vitamin D. Scientists from the Rockefeller University were surprised to find that taking vitamin D supplements do not seem to reduce the risk of -cholesterol-related cardiovascular disease.
-It is important for the metabolism of fat soluble vitamins, including vitamins A, D, E, and K
-It insulates nerve fibers
The amount of cholesterol in human blood can vary from 3.6 mmol/liter to 7.8 mmol/liter. The National Health Service (NHS), UK, says that any reading over 6 mmol/liter is high, and will significantly raise the risk of arterial disease. The UK Department of Health recommends a target cholesterol level of under 5 mmo/liter. Unfortunately, two-thirds of all UK adults have a total cholesterol level of at least five (average men 5.5, average women 5.6).
Symptoms of high cholesterol do not exist alone in a way a patient or doctor can identify by touch or sight. Symptoms of high cholesterol are revealed if you have the symptoms of atherosclerosis, a common consequence of having high cholesterol levels.
These can include:
-Narrowed coronary arteries in the heart (angina)
-Leg pain when exercising - this is because the arteries that supply the legs have narrowed.
-Blood clots and ruptured blood vessels - these can cause a stroke or TIA (mini-stroke).
-Ruptured plaques - this can lead to coronary thrombosis (a clot forming in one of the arteries that delivers blood to the heart). If this causes significant damage to heart muscle it could cause heart failure.
-Xanthomas - thick yellow patches on the skin, especially around the eyes. They are, in fact, deposits of cholesterol. This is commonly seen among people who have inherited high cholesterol susceptibility (familial or inherited hypercholesterolaemia).
Cholesterol levels may be measured by means of a simple blood test. It is important not to eat anything for at least 12 hours before the blood sample is taken. The blood sample can be obtained with a syringe, or just by pricking the patient's finger. The blood sample will be tested for LDL and HDL levels, as well as blood triglyceride levels. The units are measure in mg/dl (milligrams/deciliter) or 5mmol/liter (millimoles/liter).