Cholesterol (cont.)

The liver manufactures and secretes LDL cholesterol into the blood. It also removes LDL cholesterol from the blood by active LDL receptors on the surface of its cells. A decrease number of liver cell LDL receptors is associated with high LDL cholesterol blood levels.

Both heredity and diet have a significant influence on a person's LDL, HDL and total cholesterol levels. For example, familial hypercholesterolemia (hyper= more + cholesterol + emia= in blood) is a common inherited disorder whose victims have a diminished number or nonexistent LDL receptors on the surface of liver cells. People with this disorder also tend to develop atherosclerosis and heart attacks during early adulthood.

Diets that are high in saturated fats and cholesterol raise the levels of LDL cholesterol in the blood. Fats are classified as saturated or unsaturated (according to their chemical structure). Saturated fats are derived primarily from meat and dairy products and can raise blood cholesterol levels. Some vegetable oils made from coconut, palm, and cocoa are also high in saturated fats.

Lowering LDL cholesterol is currently one of the primary public health initiatives preventing atherosclerosis and heart attacks. The benefits of lowering LDL cholesterol are:

• Reducing or stopping the formation of new cholesterol plaques on the artery walls
• Reducing existing cholesterol plaques on the artery walls and widening the arteries
• Preventing the rupture of cholesterol plaques, which initiates blood clot formation and blocks blood vessels
• Decreasing the risk of heart attacks
• Decreasing the risk of strokes
• Decreasing the risk of peripheral artery disease

The same measures that decrease narrowing in coronary arteries also may benefit the carotid and cerebral arteries (arteries that deliver blood to the brain) as well as the femoral arteries that supplies blood to the legs.