Cholesterol :: The Good, Bad & The Ugly

Three major classes of lipoproteins are found in the serum of a fasting individual: low density lipoproteins (LDL), high density lipoproteins (HDL), and very low density lipoproteins (VLDL).

LDL Cholesterol: Bad Cholesterol

LDL cholesterol makes up 60-70 per cent of the total serum cholesterol. LDL is the major atherogenic lipoprotein and has been long ago identified as a primary target for cholesterol lowering therapy. LDL cholesterol is called "bad" cholesterol, because elevated levels of LDL cholesterol are associated with an increased risk of coronary heart disease. LDL lipoprotein deposits cholesterol on the artery walls, causing the formation of a hard, thick substance called cholesterol plaque. Over time, cholesterol plaque causes thickening of the artery walls and narrowing of the arteries, a process called atherosclerosis.

The liver not only manufactures and secretes LDL cholesterol into the blood; it also removes LDL cholesterol from the blood. A high number of active LDL receptors on the liver surfaces is associated with the rapid removal of LDL cholesterol from the blood and low blood LDL cholesterol levels. A deficiency of LDL receptors is associated with high LDL cholesterol blood levels.

HDL Cholesterol: Good Cholesterol

HDL cholesterol is called the "good cholesterol" because HDL cholesterol particles prevent atherosclerosis by extracting cholesterol from the artery walls and disposing of them through the liver. Thus, high levels of LDL cholesterol and low levels of HDL cholesterol (high LDL/HDL ratios) are risk factors for atherosclerosis, while low levels of LDL cholesterol and high level of HDL cholesterol (low LDL/HDL ratios) are desirable.

HDL cholesterol makes up 20-30 percent of the total serum cholesterol. Clinical evidence indicates that HDL helps protect against development of atherosclerosis. It is advisable to check your HDL levels from time to time.

VLDL Cholesterol: Ugly Cholesterol

The VLDL is triglyceride-rich lipoproteins and contains 10-15 percent of the total serum cholesterol .VLDL are produced by the liver and some VLDL remnants seem to promote atherosclerosis similar to LDL.

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