Cholesterol is produced by the liver, the intestines and nearly all tissues in the body. Cholesterol is needed for the production of hormones, vitamin D, and the bile necessary to digest fats in food. Cholesterol also protects cell membranes from changes in temperature. Although a certain amount of cholesterol is needed, too much is unhealthy. An excessive amount of cholesterol can block blood flow in the arteries, which can lead to a stroke. High cholesterol does not have symptoms, but a simple blood test can determine its presence. Cholesterol levels can be controlled or reduced with an active and healthy lifestyle, although, in some cases, medication will be necessary.
Types of Cholesterol
There are three different types of cholesterol. Different blood tests are performed to individually measure each one.
High-density lipoprotein (HDL) is the "good" cholesterol, because elevated levels may reduce the risks for heart disease or stroke. It is believed that HDL returns excess cholesterol to the liver for elimination from the body.
Low-density lipoprotein (LDL) makes up the majority of the body's cholesterol. It is considered to be "bad" cholesterol, because it builds up in the walls of the arteries, causing them to narrow, blocking blood flow, and leading to heart disease or stroke.
Very-low-density lipoprotein (VLDL) is composed of cholesterol, triglycerides and proteins. VLDL contains more triglycerides than any other lipoprotein, and is considered to be a "bad" type of cholesterol.
A total cholesterol test measures all types of cholesterol in the blood, and results indicate whether "bad" cholesterol levels are too high.
Risk Factors for High Cholesterol
Risks for developing high cholesterol increase with age. Factors that put people at higher risk for developing high cholesterol include the following:
- Poor diet, high in saturated fat
- High blood pressure
- Lack of regular exercise
People with family histories of high cholesterol and heart disease have a greater risk of developing high cholesterol.
Complications of High Cholesterol
High-cholesterol levels increase the risk of developing heart disease, the leading cause of death in the United States. High levels of "bad" cholesterol can lead to serious complications, including the following:
- Coronary artery disease
- Heart attack
Initially, high cholesterol can cause atherosclerosis, an accumulation of cholesterol and fat deposits on the walls of the arteries. Atherosclerosis can then cause any of the conditions listed above.
Treatment of High Cholesterol
A low-fat diet and losing weight may help lower LDL and triglyceride levels. Although these lifestyle changes are usually effective in treating high cholesterol, they may not be enough. If lifestyle changes have been made, and total cholesterol levels remain high, the following medications may be suggested:
- Statin medication (to reduce LDL cholesterol levels)
- Niacin (nicotinic acid) (to raise HDL levels and lower LDL levels)
- Fibrates (to reduce triglyceride levels)
- Bile acid sequestrants (to eliminate bile acids)
Many medications have side effects, so it is important to discuss any concerns with a doctor before taking them.
- National Institutes of Health
- Centers for Disease Control and Prevention
- Eunice Kennedy Shriver National Institute of Child Health and Human Development
- U.S. Department of Health & Human Services
- U.S. National Library of Medicine
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