Biological Role of LDL

Unable to mix well with blood and easily flow through arteries, cholesterol requires a way to move from production in the liver, onward throughout the body. The biological role of LDL is to provide just this type of transportation.

Identification

• Lipoproteins find themselves classified as low-density (LDL) and high-density (HDL), with LDL also called “bad” cholesterol and HDL “good” cholesterol. Physicians judge the amount of cholesterol in the blood by measuring these twice.

Significance

• LDL plays an important role in human health. “Cholesterol forms part of the outer membrane that surrounds every cell,” according to a British Broadcasting Corporation by report Dr. Trisha Macnair. “It's used to insulate nerve fibers (and so make nerve signals travel properly) and make hormones, which carry chemical signals around the body.”

Function

• LDL “drops off” cholesterol at a cell for absorption. When that cell is full of necessary cholesterol, it refuses any more, and the left-over cholesterol begins to buildup. This results in the cardiovascular disease known as atherosclerosis.

Transportation

• The majority of cholesterol movement takes place via LDL with only “About one-fourth to one-third of blood cholesterol carried by high-density lipoprotein (HDL),” says the American Heart Association.

Considerations

• Levels of LDL above 100 mg/dL are considered dangerous in either sex while HDL amounts should exceed 40 mg/dL in men and 50 mg/dL in women.