In normal individuals the uptake of dietary cholesterol inhibits the cells own synthesis of cholesterol. As a consequence the number of LDL-receptors on the cell surface is reduced. This leads to increased levels of cholesterol in the blood which subsequently may accumulate in the wall of arteries causing atherosclerosis and eventually a heart attack or a stroke. Brown and Goldstein's discoveries have lead to new principles for treatment, and prevention, of atherosclerosis. The cholesterol debate during the last decade may have given the public the impression that cholesterol is something you have to avoid to survive.
Cholesterol is also vitally important for several of the normal processes in the body.
Cholesterol originates from two main sources - from within through biosynthesis predominantly in the liver, and from without through fat in the food. In the liver as well as in the intestine cholesterol is packeted into particles in such a way that it can be transported in the blood and lymphatic fluid. These particles are called lipoprotein - a combination of fat and proteins. Its core consists of some 1,500 cholesteryl esters, each a cholesterol molecule attached by an ester linkage to a long fatty acid chain. A normal healthy person has approximately 2 g cholesterol per liter plasma.