Cholesterol

Cholesterol comes from and is needed to produce the cell membranes of living tissue. It does not dissolve in blood, and is a precursor to certain steroids such as cortisol, aldosterone, and vitamin D. A person's cholesterol level will go up when he or she eats a high-fat diet, but a person can also have an intrinsic level of cholesterol that is genetically determined. Cholesterol levels rise when the weather is cold and increase between the ages of 20 and 60.

High cholesterol levels increase the risk of cerebrovascular and cardiovascular problems; disease risk increases in proportion to the cholesterol level. Low cholesterol levels are rare and, when seen, are associated with depression and certain types of cancer. In physically active individuals, the risk of cholesterol depositing in the lining of arteries decreases. There are no symptoms of high cholesterol levels. Diagnosis is made with the aid of laboratory testing, and simple tests will provide one number for the total cholesterol level.

The body will bind cholesterol to lipoproteins (low density, triglycerides, or high density) that circulate in the bloodstream. Cholesterol bound to high-density lipoproteins will not deposit cholesterol on the arterial lining; however, cholesterol attached to low-den-sity lipoproteins, or triglycerides, will.