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Categories > Heart Health > Cholesterol

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Taking the confusion out of cholesterol

» What is cholesterol?

» The effect of dietary cholesterol on blood cholesterol

» LDL, HDL and triglycerides: The cholesterol transportation system

“Good” vs. “bad” cholesterol

LDL cholesterol is known as the “bad” cholesterol because it leaves the bloodstream and is deposited in artery walls, causing plaque to build up. HDL cholesterol is called “good” because it carries cholesterol out of the arteries and back to the liver for reprocessing or excretion.

Heart disease and the cholesterol connection

Heart disease that involves the deposit of fatty substances in the inner lining of an artery is called atherosclerosis. As excess cholesterol and other substances are deposited in the artery, they create plaque. Plaque may partially or totally block the blood’s flow through an artery.

Atherosclerosis is a slow, progressive disease that may begin as early as childhood. In general, it doesn’t become threatening until age 40 or 50.

What you can do

Getting regular checkups that include not only your total cholesterol count, but your LDL, HDL, and triglyceride counts as well, can alert you to your risk for atherosclerosis. But knowing your numbers isn’t enough. Ask your doctor to interpret the numbers and to help you create a plan that includes nutritional changes as well as other lifestyle modifications, and perhaps medication. Remember, your cholesterol counts and risk if heart disease are not carved in stone. They can change as long as you’re willing to!

Cholesterol guidelines: Where do you fit?

The National Cholesterol Education Program has developed these guidelines to help you understand the risk.

Total cholesterolLDL cholesterolHDL cholesterolTriglycerides 
Optimal Under 100Above 60 
DesirableUnder 200100–12940–59Less than 150
Borderline200–239130–159 150–199
AbnormalOver 240Over 160Below 40200 or over

Today, doctors consider much more than “total” cholesterol levels to evaluate a person’s risk. Physicians look carefully at the HDL, LDL and triglyceride levels-and their relationship to each other.

We think about it, talk about it and read about it regularly. We can hardly eat a meal without analyzing it. It’s cholesterol, and despite a seeming avalanche of information, many of us are still confused. But here’s some good news: You are about to understand exactly what cholesterol is and how it affects you.

What is cholesterol?

Cholesterol is a soft, waxy, fat-like substance. Many people are surprised to find out that cholesterol is essential to life.

In fact, it is not the presence of cholesterol, but the amount, that can turn it from helpful to harmful. Found in all animal tissues, cholesterol is used to form cell membranes, certain hormones and other necessary substances. In addition to its presence in human tissues, cholesterol is also found in the bloodstream, where it is transported throughout the body.

People get cholesterol in two ways. One way is from the liver, which manufactures cholesterol from fat and other substances. The other way is by eating foods that contain cholesterol. Typically, our livers make more cholesterol than our bodies need. The cholesterol we get straight from food is pure excess.

The effect of dietary cholesterol on blood cholesterol

People often assume that dietary cholesterol determines the blood cholesterol level. While cholesterol in the diet does make a contribution, it’s the fat in the food you eat—trans fats and saturated fats in particular—that does the most damage, causing the liver to make too much cholesterol. So the best way to decrease your blood cholesterol level is to reduce the amount of these fats in your diet.

LDL, HDL and triglycerides: The cholesterol transportation system

Cholesterol is carried through the bloodstream inside little particles called lipoproteins. To understand atherosclerosis and heart disease, you need to understand low-density lipoproteins, or LDLs, and high-density lipoproteins, or HDLs. Cholesterol carried by LDLs is called LDL cholesterol and cholesterol carried by HDLs is called HDL cholesterol.

LDL cholesterol is considered to be the “bad” cholesterol because it leaves the bloodstream and is deposited in artery walls, causing plaque to build up. The higher the LDL, the greater the risk of atherosclerosis. About two-thirds of cholesterol is carried by LDLs.

HDL is often called “good” cholesterol because it carries cholesterol out of the arteries and back to the liver for reprocessing or excretion. Because HDL clears cholesterol out of the system, high levels of HDL are associated with a decreased risk for heart disease.

Triglycerides are a type of fat that binds with protein in the bloodstream to form LDL cholesterol; high triglyceride levels are associated with increased risk of heart disease.

Understanding the numbers: What does “total” cholesterol mean?

Until a few years ago, when people would ask for the results of their cholesterol blood test, they would be given only one three-digit number. This number is the total cholesterol, which experts recommend you keep at no more than 200 milligrams per deciliter.

These days, heart disease risk is assessed by looking not only at total cholesterol, but at the amounts of HDL, LDL, and triglycerides as well. That’s because people with the same total cholesterol number can have different amounts of these cholesterol components. For instance, if two people each have a total cholesterol count of 200, but one has an HDL count of 36 and the other has an HDL count of 65, the person with the HDL count of 65 has a much lower risk of heart disease. The charts in the sidebar can help you understand how your HDL, LDL and triglyceride counts are calculated to assess your risk.


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