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What is Bad Cholesterol?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

So-called “bad cholesterol” is a lipid naturally present in the body which performs a number of important functions. It is officially known as low density lipoprotein (LDL), and together with high density lipoprotein (HDL) and triglycerides, it combines to create blood cholesterol. Levels of blood cholesterol can be determined with a blood test, in which the total value is determined to provide insight into a patient's general health. A high level of cholesterol is generally perceived as a bad thing, because LDL can cause serious health problems.

The body produces cholesterol in the liver, through the conversation of saturated fats and transfatty acids. It is also possible to elevate cholesterol levels by eating a large amount of dietary cholesterol, cholesterol which is found in animal products. The body needs these lipids to perform various functions including the creation of new cells, making it an important part of the complex system which keeps the human body in good working order.

High levels of LDL cholesterol increase risk for hardening of the arteries or artery blockage.
High levels of LDL cholesterol increase risk for hardening of the arteries or artery blockage.

LDL is known as bad cholesterol because it can tend to accumulate in the walls of the arteries, creating a thick plaque by binding with other substances which float in the blood. Over time, the plaque can harden and cause the artery to narrow, leading to a condition known as atherosclerosis. Narrowed arteries are less able to transport blood, and atherosclerosis can lead to heart attacks and other cardiovascular problems.

Fatty foods often are high in cholesterol.
Fatty foods often are high in cholesterol.

By contrast, HDL or good cholesterol appears to reduce the risk of heart attacks because it transports excess cholesterol back to the liver so that the liver can break it down and eliminate it. This is why people are encouraged to eat unsaturated fats and other foods which elevate good cholesterol levels, taking care to avoid or reduce the intake of foods which increase bad cholesterol.

Angioplasty may be used to treat clogged coronary arteries caused by high levels of LDL cholesterol in the blood.
Angioplasty may be used to treat clogged coronary arteries caused by high levels of LDL cholesterol in the blood.

Several things appear to contribute to levels of bad cholesterol in the blood. Diet is the biggest factor, since the body's production levels are limited by the amount of raw materials it can access. The role played by dietary cholesterol appears to be a bit unclear, with some studies suggesting that foods which are high in cholesterol will elevate bad cholesterol levels, while others contradict this claim. Genetics may be involved as well, as are exercise levels. The body will convert consumed fats into energy if asked to do so, while someone who lives a sedentary life will not burn these fats for energy, allowing them to reach the liver for conversion into LDL cholesterol.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

johnycharles

smartlipo. I believe while cholesterol has an alcohol group attached, that cholesterol belongs to a group of compounds called ’Sesterterpenes’ a 25 carbon ’based’ (sometimes additional methyl groups are substituted) terpenoid.

anon71265

Thanks for the update. Cholesterol is classed as a steroid which is actually a metabolic derivative of terpenes. smart lipo

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    • High levels of LDL cholesterol increase risk for hardening of the arteries or artery blockage.
      By: Alexandr Mitiuc
      High levels of LDL cholesterol increase risk for hardening of the arteries or artery blockage.
    • Fatty foods often are high in cholesterol.
      By: Bill
      Fatty foods often are high in cholesterol.
    • Angioplasty may be used to treat clogged coronary arteries caused by high levels of LDL cholesterol in the blood.
      By: designua
      Angioplasty may be used to treat clogged coronary arteries caused by high levels of LDL cholesterol in the blood.
    • Consuming peanuts on a regular basis may help lower cholesterol levels.
      By: lirtlon
      Consuming peanuts on a regular basis may help lower cholesterol levels.
    • Increasing HDL levels can help lower LDL levels.
      By: rob3000
      Increasing HDL levels can help lower LDL levels.