Cholesterol is the complex alcohol constituent of all animal
fats and oils. It can be activated to form vitamin D. Cholesterol is one of a
group of compounds known as sterols and is related to such other sterols as the
sex hormones and the hormones of the adrenal cortex.
A close relationship exists among levels of blood
cholesterol in the body, those of other fats or lipids, and the development of
atherosclerosis. In this disorder, plaques containing cholesterol are deposited
on the walls of arteries, particularly those of small and medium size, reducing
their inside diameter and the flow of blood. Clotting of blood, such as may occur
in the coronary arteries to cause a heart attack, is most likely to develop at
places where arterial walls are roughened by such plaques.
Although many foods, particularly dairy products and meat fat, contain cholesterol, the body also synthesizes this sterol from cholesterol-free substances. Nevertheless, investigation indicates that a cholesterol-rich diet causes abnormally high levels of cholesterol and the related fats and lipids in the blood. Evidence strongly indicates that people with such high levels are more likely to develop atherosclerosis and heart attacks than those with lower levels. Also significant is the fact that scientists have identified two forms of cholesterol-carrying proteins in the blood, called high-density and low-density lipoproteins. The low-density form is thought to promote atherosclerosis, whereas the high-density component may retard it. In 1984, the United States National Heart, Lung and Blood Institute reported results of a study indicating that high levels of low-density lipoproteins also increased the risk of heart attacks and heart disease. (Encarta encyclopedia)
Although many foods, particularly dairy products and meat fat, contain cholesterol, the body also synthesizes this sterol from cholesterol-free substances. Nevertheless, investigation indicates that a cholesterol-rich diet causes abnormally high levels of cholesterol and the related fats and lipids in the blood. Evidence strongly indicates that people with such high levels are more likely to develop atherosclerosis and heart attacks than those with lower levels. Also significant is the fact that scientists have identified two forms of cholesterol-carrying proteins in the blood, called high-density and low-density lipoproteins. The low-density form is thought to promote atherosclerosis, whereas the high-density component may retard it. In 1984, the United States National Heart, Lung and Blood Institute reported results of a study indicating that high levels of low-density lipoproteins also increased the risk of heart attacks and heart disease. (Encarta encyclopedia)
