Cholesterol is oil-based and so does not mix with the blood, which is water-based. It is therefore carried around the body in the blood by lipoproteins. Lipoproteins, in order of molecular size, largest to smallest, are chylomicrons, very low-density lipoprotein (VLDL),intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), and HDL.
The parcels of cholesterol are carried by two types of lipoprotein:
Low-density lipoprotein (LDL - cholesterol carried by this type is known as 'bad' cholesterol)
High-density lipoprotein (HDL - cholesterol carried by this type is known as 'good' cholesterol).
HDL cholesterol absorbs cholesterol and carries it back to the liver, which flushes it from the body. HDL is known as “good” cholesterol because having high levels can reduce the risk for heart disease and stroke. Where LDL cholesterol makes up the majority of the body’s cholesterol. LDL is known as “bad” cholesterol because having high levels can lead to plaque buildup in your arteries and result in heart diseaseand stroke.
Cholesterol has four main functions, without which we could not live. It: Contributes to the structure of cell walls
Makes up digestive bile acids in the intestine
Allows the body to produce vitamin D
Enables the body to make certain hormones.
What causes high cholesterol?High cholesterol is a major risk factor for coronary heart disease, a cause of heart attacks, and reducing blood lipid levels lowers the cardiovascular risk.4
High levels of LDL lead to a build-up of cholesterol in the arteries, whereas HDL carries cholesterol to the liver for removal from the body.2 A build-up of cholesterol is part of the process that narrows arteries, called atherosclerosis, in which plaques form and cause restriction of blood flow.
Normal value of Cholesterol in blood serum is-
<200 mg/dL (Normal)
200-240 mg/dL (Borderline High)
>240 mg/dL (High)
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