What is Cholesterol?

Cholesterol is a substance that helps your body in many ways. It’s a building block of your cell membranes. It also helps your body create bile, hormones and vitamin D. You need cholesterol. But too much of it in your blood can raise your heart disease risk. So, learn your cholesterol numbers and talk with your healthcare provider about what they mean.

What is cholesterol in simple terms?

Cholesterol is a type of lipid that performs many essential jobs in your body. Lipids are substances that don’t dissolve in water, so they don’t come apart in your blood. Instead, they travel through your blood to reach different parts of your body that need them.

Your liver makes enough cholesterol to support your body’s needs. But you also get extra cholesterol from the foods you eat. Your body has a system for getting rid of excess cholesterol. But sometimes, that system doesn’t work as well as it should or becomes overloaded. As a result, you can have extra cholesterol circulating in your blood. And that’s when you might run into trouble.

Cholesterol itself isn’t bad. It’s actually vital for you to live. But too much cholesterol can be harmful. That’s why it’s important to learn about cholesterol, including its functions and types. This knowledge can help you understand why you need cholesterol — but not too much of it. It can also help you understand what your cholesterol numbers mean and how to take action to lower them if needed.


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What is the function of cholesterol?

Cholesterol has many important functions in your body. These include:

  • Helping your cell membranes form protective layers. These layers control what can enter or leave your cell.
  • Helping your liver make bile, which you need to digest food.
  • Supporting your body’s production of certain hormones (including sex hormones) and vitamin D.

If cholesterol is necessary, why do I have to worry about how much I have?

Having enough cholesterol to meet your needs is important. Having too much cholesterol can cause problems. People with high cholesterol (hyperlipidemia) or an abnormal ratio of lipids (dyslipidemia) face a higher risk of coronary artery disease.

Your body produces all the cholesterol it needs to function. In fact, your liver makes about 80% of all the cholesterol in your body. The rest (which your body doesn’t need) comes from your food. Usually, your body can filter out the cholesterol it doesn’t need. But many factors can affect your body’s ability to keep your cholesterol levels balanced.

For example, genetic conditions like familial hypercholesterolemia play a role. Such conditions prevent your body from getting rid of extra cholesterol. So, it builds up in your bloodstream over time.

Your diet also plays a role. Eating foods high in saturated fat or trans fat can raise your cholesterol levels. You mostly find saturated fat in products that come from animals, like meat, milk, cheese and butter. Trans fat is in many processed foods and fast foods. So, paying attention to how your diet affects your cholesterol levels can help you avoid having too much cholesterol in your body.

Where is cholesterol found in my body?

You have cholesterol molecules in all the cells in your body. But you’re probably most familiar with it as something that travels in your blood.

Cholesterol has a chemical makeup that prevents it from traveling solo through your blood. It needs to be attached to other molecules. So, it teams up with proteins and another type of lipid called triglycerides. These molecules bind together to form a particle called a lipoprotein.


What are lipoproteins?

A lipoprotein is a combination of lipids and proteins that’s able to travel through your blood. Lipoproteins are like little boats that travel from town to town. Some boats deliver food and supplies to each town. Other boats pick up trash and carry it away.

Inside your body, you have lipoproteins that deliver cholesterol to your body’s tissues. This cholesterol is important for your body to function. But too much of it is bad for you. That’s why you need other lipoproteins that pick up the extra cholesterol and carry it away.

You might know these lipoproteins by their nicknames. They’re usually known as LDL cholesterol and HDL cholesterol. These are the two main types of cholesterol. But there are other types, too. So, let’s take a closer look at the types of cholesterol and what they do in your body.

What are the different types of cholesterol?

Your body contains several types of cholesterol. You’ll see them listed on your lipid panel results. Learning what each type means can help you talk about your cholesterol with your healthcare provider.

What is LDL cholesterol?

LDL cholesterol refers to low-density lipoproteins. These particles are made mostly of cholesterol, which they deliver to your body’s cells. LDLs have a reputation for being the “bad” cholesterol. Why?

LDLs are important to your body. But they become bad when you have too many of them circulating in your blood. They can combine with other substances and build up on the walls of your arteries. These fatty deposits form plaque that gets bigger over time. This plaque growth is called atherosclerosis, and it raises your risk of a heart attack, stroke and other diseases.

Your LDL cholesterol is a number you want to keep low. For most adults, that means keeping it below 100 mg/dL. If you have a history of atherosclerosis, you should keep your LDL cholesterol below 70 mg/dL.

What is HDL cholesterol?

HDL cholesterol refers to high-density lipoproteins. These lipoproteins are made mostly of protein. HDL is the “good” cholesterol because it takes extra cholesterol out of your bloodstream and transports it to your liver. Your liver then breaks down the cholesterol and gets rid of it. This process is called reverse cholesterol transport.

Your HDL cholesterol is a number you want to keep high. Men and people assigned male at birth (AMAB) should aim for an HDL of at least 40 mg/dL. Women and people assigned female at birth (AFAB) should aim for an HDL of at least 50 mg/dL.

An HDL above 60 is ideal for all adults and may lower your risk of heart disease.

What is VLDL cholesterol?

VLDL cholesterol refers to very low-density lipoproteins. VLDLs carry triglycerides and cholesterol, and their protein content is low. Like LDLs, they’re “bad” because they can contribute to plaque buildup in your arteries.

Illustration of healthy artery vs. narrow artery. Bad cholesterol (LDL) contributes to plaque formation in the narrow artery.

Good cholesterol (HDL) helps remove bad cholesterol (LDL) from your blood. LDL cholesterol contributes to plaque formation in your arteries.


What factors affect my cholesterol levels?

Many factors can affect your cholesterol levels. These include:

  • Age: As you get older, your cholesterol levels rise.
  • Diet: Saturated fat and trans fat in the foods you eat raise your LDL levels. This is the “bad” cholesterol you want to keep low. Reducing your intake of saturated and trans fats can help you lower your cholesterol.
  • Exercise: Regular exercise can raise your HDL. This is the “good” cholesterol. Aim for 30 minutes of physical activity on most days of the week.
  • Heredity: Your genes partly determine how much cholesterol your body makes. High blood cholesterol can run in families.
  • Sex assigned at birth: Before menopause, people assigned female at birth usually have lower total cholesterol levels than people assigned male at birth who’re the same age. But after menopause, their LDL levels tend to rise and their HDL can drop.

Should I get my cholesterol checked?

Everyone should get their cholesterol checked. How often you receive a cholesterol test (lipid panel) depends on your age and your risk factors for heart disease. Talk with your healthcare provider about how often you should get your cholesterol checked. Knowing your numbers is an important step in learning your risk for heart disease.

If your cholesterol is high, your provider will recommend treatment. Treatment options include:

  • Dietary changes.
  • Lifestyle changes.
  • Medications (like statins).

For many people, a combination of these methods is most helpful. But you won’t know what’s best for you until you get your numbers checked and talk with your provider.

So, make it a point to visit your provider if it’s been a while. And keep going back according to the schedule your provider recommends. Learn your cholesterol, blood pressure and other numbers that help show the health of your heart and blood vessels. It’s never too early to think about your heart health and what you can do to improve it.

A note from Cleveland Clinic

Cholesterol is a lipid that performs important jobs in your body. You need cholesterol to survive. But too much cholesterol in your blood can be dangerous for you. That’s why it’s important to get your cholesterol checked and talk with your healthcare provider about what your numbers mean.

Medically Reviewed

Last reviewed on 08/03/2022.

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