High-density lipoprotein (HDL) cholesterol is known as the "good" cholesterol because it helps remove other forms of cholesterol from the bloodstream. A higher level of HDL cholesterol is linked to a lower risk of heart disease.

Cholesterol is a waxy substance that's in every cell in the body. At healthy levels, cholesterol does useful work. This includes helping the body's cells work as they should. HDL moves through the bloodstream on proteins called lipoproteins.

The two main types of lipoproteins that carry cholesterol are:

• Low-density lipoprotein (LDL) cholesterol. High levels of LDL can build up within the walls of the blood vessels over time. This narrows the passageways.

  Sometimes a clot forms and gets stuck in the narrowed space. This causes a heart attack or stroke. This is why LDL cholesterol also is called the "bad" cholesterol.

• High-density lipoprotein cholesterol. HDL cholesterol is often called the "good" cholesterol. HDL cholesterol picks up excess cholesterol in the blood. It carries the cholesterol back to the liver. After the liver breaks down the cholesterol, the liver flushes it from the body.

If you have high LDL and low HDL cholesterol levels, your healthcare professional looks at lowering your LDL cholesterol first. Medicines known as statins are the most common treatment for high LDL cholesterol. Examples are atorvastatin (Lipitor) and simvastatin (Zocor).