It is important to learn about HDL and LDL, and the effects these lipoproteins have on cholesterol levels and on your cardiovascular system. More than 102 million American adults had high cholesterol in 2010. According to the Centers for Disease Control and Prevention, 35 million of those had levels high enough to put them at risk for developing heart disease.
Anatomy
Cholesterol is a naturally occurring component in your body, necessary for the production of bile acids and skin oils. Bile production accounts for most of the cholesterol in your body. Only a small amount of cholesterol enters the bloodstream. Cholesterol is important in the manufacture of hormones like estrogen and testosterone and for metabolizing vitamins A, D, E and K. Cholesterol is present in the membrane of every cell in your body.
Cholesterol
Your liver produces most of the cholesterol in your body. You get the rest through the food you eat. Cholesterol moves from your gut via the bloodstream to the cells of the body, including the cells that line the inside of blood vessels. Cholesterol is a lipid, which means it is a fat-like substance that is not soluble in blood's watery plasma. The body overcomes this by packaging lipids onto proteins to create special lipoproteins that flow through the bloodstream.
LDL
Scientists classify lipoprotein according to density. Low-density lipoprotein, or LDL, carries cholesterol from the gut to the awaiting cells. LDL is most closely associated with heart disease because this role of introducing more cholesterol into the bloodstream. Excess cholesterol and other fatty substances build up in the blood and accumulate inside blood vessel walls. This accumulation injures arteries and narrows the space blood has to flow, a condition that leads to heart disease.
HDL
High-density lipoprotein, or HDL, scrapes excess cholesterol from arterial walls and deliver it back to the liver where it is processed and eliminated from the body. HDL keeps LDL levels in balance, and lowers your risk for cardiovascular disease. This action gives HDL a reputation as good cholesterol. HDL carries one-third to one-quarter of the cholesterol in your bloodstream, according to the American Heart Association.
Normal Levels
Doctors consider lower levels of LDL as healthy. A normal LDL level is less than 100 mg/dL. Lower levels of LDL are associated with reduced risk for heart disease. High levels of HDL are associated with lowered risk for heart disease. An HDL over 60 mg/dL provides optimal protection for your heart.
