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What is cholesterol, and why does it matter?

Cholesterol is a waxy, fat-like substance created naturally by the body and needed in small amounts to help produce some hormones and digest fat. The body makes most of the needed cholesterol for most people, although family health history may affect how each individual handles cholesterol. The rest of the body’s cholesterol needs are met through food, and cholesterol is found only in foods of animal origin.

Cholesterol itself isn’t bad, but too much cholesterol in the blood can result in plaque deposition inside the arteries. This plaque buildup can narrow and block arteries, increasing risk for heart disease or stroke. There are different types of blood cholesterol: HDL cholesterol (sometimes called “good cholesterol”) and LDL cholesterol (sometimes called “bad cholesterol”). High levels of total blood cholesterol or LDL cholesterol, as well as not enough HDL cholesterol, can increase cardiovascular risk.

In the U.S., experts estimate that about 1 in 6 adults has high blood cholesterol. The condition has no symptoms, so many people are unaware of their increased risk. A simple blood test can determine your total blood cholesterol level and can distinguish the HDL and LDL cholesterol levels in your blood.

Lifestyle and dietary steps you can take to prevent or reduce high blood cholesterol once you’re aware of the condition include: choose healthy fats, limit saturated fats, avoid trans fats, and increase fiber in your diet; maintain a healthy weight; and increase your physical activity. Your doctor may also prescribe a cholesterol-lowering medication.

Internet Resources

MedlinePlus: Cholesterol
This National Library of Medicine portal for consumers includes government-sponsored and privately developed health information, ranging from general overviews to the latest news and research. You will find comprehensive information about cholesterol and health and the prevention and control of high cholesterol. An interactive tutorial is included.

National Heart Lung and Blood Institute: Your Guide to Lowering Your Cholesterol with TLC [Therapeutic Lifestyle Changes]
This site is a consumer guide to high cholesterol, why it matters, and how to make lifestyle changes to lower it.

Mayo Clinic: Cholesterol Test
This site provides an overview as well as in-depth information about the cholesterol test or blood test for measuring cholesterol levels -- also called a “complete lipid profile” or “lipid panel.” Learn when the test is used, how to prepare for it (you may be asked to fast for 9-12 hours prior to the test), and how to interpret test results.

Harvard School of Public Health: Fats and Cholesterol. The Bottom Line
Learn about the different types of fats and examples of healthy food choices, and find information on how dietary fat affects cholesterol levels and how to control these levels.

American Heart Association (AHA): Cholesterol
http://www.heart.org/HEARTORG/Conditions/Cholesterol/Cholesterol_UCM_001089_SubHomePage.jsp AHA provides information about cholesterol, why it matters, assessing your cardiovascular risk, prevention and treatment of high cholesterol, tips for heart healthy eating and cooking, and many other resources.


  • AHA guidelines and scientific statements handbook. Fuster V. 2009.
  • American Medical Association Guide to Preventing and Treating Heart Disease: Essential Information You and Your Family Need to Know About Having a Healthy Heart. Lipsky MS. 2008.
  • Low-fat, low-cholesterol cookbook: delicious recipes to help lower your cholesterol. American Heart Association. 2008.
  • Cleveland Clinic Healthy Heart Lifestyle Guide and Cookbook. Polin BS. 2007.
  • The Great Cholesterol Con. Kendrick M. 2007.
  • What your doctor may not tell you about cholesterol : the latest natural treatments and scientific advances in one breakthrough program. Devries SR. 2007.
  • Cholesterol Down: Ten Simple Steps to Lower Your Cholesterol in Four Weeks, Without Prescription Drugs. Brill JB. 2006.
  • Get the Trans Fat Out. Hobbs SH. 2006.
  • Love in the time of Cholesterol: a memoir with recipes. Ross C. 2006
  • Beyond cholesterol: 7 life-saving heart disease tests that your doctor may not give you. Torelli J. 2005

Journal Articles

  • “Are abnormal lipid levels harmful in young adults?” Annals of Internal Medicine Summaries for Patients. 2010. http://www.annals.org/content/153/3/I-25.full.pdf
  • “HDL: the good, but complex, cholesterol.” Harvard Heart Letter, 20(7):1-2. Mar 2010.
  • “Too much of a good thing: your body needs cholesterol to function, but it can also make serious trouble.” Gebel E. Diabetes Forecast. 62(1):19-21. January 2009.
  • “Health tips: good eats to lower cholesterol.” Mayo Clinic Health Letter. 26(11):3. November 2008.
  • “New vitamin helps lower cholesterol.” Harvard Heart Letter, 18(5):7. January 2008.
  • “Good, bad, and ugly. The inside story of blood lipids and your body.” Diabetes Forecast, 60(13):36-37. December 2007.
  • “Lowering Cholesterol: Is there a Limit?” Harvard Men’s Health Watch, 11(10):5–6. May 2007.
  • “Cholesterol, the Mind, and the Brain.” Harvard Men’s Health Watch, 11(8):1–4. March 2007.
  • “Medical Memo: Stress and Cholesterol.” Harvard Men’s Health Watch, 11(7):7–8. February 2007.


  • High Cholesterol: An Introduction to Treatment. 13 min.


  • Human Coronary Artery, showing normal, narrowed, and blocked conditions.

NMH Patient Education Brochures

  • Heart Healthy Nutrition
  • Modify Your Lifestyle to Reduce Your Risk for Heart and Vascular Disease

Contact Us

For more information, please contact the Health Learning Center at 312-926-5465 or HLC@nmh.org.

Last UpdateJune 19, 2012