What is a Low-Density Lipoprotein?

A low-density lipoprotein (LDL) is one of the classes of lipoproteins found in the blood. It is also known as the "bad" cholesterol, as its presence in high amounts can lead to the development of cardiovascular diseases. Low-density lipoprotein is responsible for carrying cholesterol and fats in the blood. These lipoproteins have the capacity to adhere to arteries and form harmful plaques, which can grow as the years go by. Arteries are the blood vessels carrying blood which is rich in oxygen towards vital organs inside the body.

Continued accumulation of plaques in the arteries can lead to atherosclerosis or narrowing of the arteries. This will often result in the limitation or blockage of blood flow towards important organs such as the heart, brain, and kidneys. Complications from such events include high blood pressure, coronary artery disease, and stroke. Arteries of the legs and arms can also be affected by atherosclerosis, often leading to pain, numbness, or frequent infections in these areas. These conditions can often be prevented with changes in lifestyle activities such cessation of smoking, following a healthy diet, and exercising regularly.

The levels of low-density lipoprotein in the blood can be detected through a blood test known as LDL test or as a part of a lipid profile test, which also includes assays for total cholesterol, triglycerides, and high-density lipoprotein (HDL) in the blood. Higher amounts of low-density lipoprotein than normal often indicate an increased risk for developing heart disease. Another disease associated with increased levels of low-density lipoprotein in the blood is familial hyperlipoproteinemia II. This is a hereditary disease characterized by high levels of low-density lipoprotein in the blood starting from birth, often leading to heart attacks during childhood.

Other classes of lipoproteins found in the blood are HDL, very low-density lipoprotein (VLDL), chylomicron, and intermediate-density lipoprotein (IDL). All five classes of lipoprotein are important in the transport and absoprtion of cholesterol, triglycerides, and fat-soluble vitamins in the body. They are classified according to their density and size, among other factors.

High-density lipoprotein, also known as the "good" cholesterol, are capable of clearing bad cholesterol in the blood. If the value of HDLs in the blood is lower than normal, this also increases a person's risk for heart disease. Management for patients with cardiovascular disease often include medications to lower the low-density lipoproteins and to increase the high-density lipoproteins in the blood.