Because of its reputation as a risk factor for heart disease, people tend to think of cholesterol only in negative terms. But cholesterol is an important component of cell membranes and vital to the structure and function of all of your body's cells. Cholesterol also is a building block in the formation of certain types of hormones.

Still, about half of American adults have blood cholesterol levels that are higher than desirable (hypercholesterolemia). If you're one of these people with this largely preventable condition, you may be on the way to heart disease.

When the levels of cholesterol and triglycerides, another blood fat, in your bloodstream become too high, your likelihood of developing cholesterol-containing fatty deposits (plaques) in your blood vessels increases. Over time, plaques lead to narrowing of arteries, impeding blood flow and creating a condition called atherosclerosis. Narrowing of the arteries around your heart (coronary artery disease) can prevent your heart from getting as much oxygen-rich blood as it needs. This means an increased risk of a heart attack. Likewise, decreased blood flow to your brain can cause a stroke, and less blood flowing to your lower limbs may result in exercise-related pain or even gangrene.