Its role. LDL is the protein package that carries most of the cholesterol in your blood. It can contribute to the buildup of plaque on the walls of your arteries. This can lead to hardening of the arteries, called atherosclerosis. The more LDL you have in your blood, the higher your risk of heart disease. This is the reason doctors call LDL cholesterol the bad cholesterol.
Its name. You may be able to remember that LDL is the bad cholesterol by thinking of it as "least desirable," which begins with the letters LD. Another way to remember that LDL is the bad type is to remember that the first L stands for "lower" - as in, "the lower the better."
Its impact. Studies have shown that, in parts of the world where people have low LDL, atherosclerosis is rare, and few people have heart attacks. If your LDL is high, don't despair. You can work with your healthcare team to get it under control and reduce your risk for heart disease and stroke.
What high levels mean. If you've been told you have high cholesterol, this may mean that you have a high total cholesterol level. Total levels include your LDL level plus your HDL level. Or, it may mean that you have an acceptable total cholesterol level but a high LDL level. Typically, healthcare providers consider a total cholesterol level of less than 200 mg/dL to be desirable. But your LDL level is the more important one to know - and to lower if it is high. An LDL level of 130 mg/dL or more is considered high. What counts as high for you may depend on your other risk factors for heart disease. According to the 2001 guidelines from the National Cholesterol Education Program, lowering your LDL can reduce your risk of heart disease over the next 10 years by as much as 40%.
To learn how to interpret your cholesterol measurements, see What Do My Test Results Mean?