What’s the Difference Between ‘Good’ and ‘Bad’ Cholesterol?

Understanding these two key concepts for a healthy heart
An illustration of two vials labeled "HDL" and "LDL"

“Cholesterol” is one of those words we all know but don’t actually know … you know? You’ve probably heard about good and bad cholesterol, as well as high and low cholesterol, but you may not be entirely sure what these terms actually mean when it comes down to your health.

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Cardiologist Leslie Cho, MD, is here to help, outlining what you need to know about cholesterol in simple, easy-to-understand terms.

She explains that low-density lipoprotein (LDL), sometimes called “bad cholesterol,” causes fatty deposits to build up in your arteries. High-density lipoprotein (HDL), or “good cholesterol,” actually helps remove the bad cholesterol from your body.

Let’s get to the heart of the matter, shall we?

HDL vs. LDL: What to know

Dr. Cho lets you in on a little secret to help you remember which kind of cholesterol is which: “HDL is good cholesterol, so think H for happy,” she says. “The bad cholesterol is called LDL — L for lousy.”

LDL, the lousy stuff, causes plaque build-up in your blood vessels, which makes them hard and narrow. This then reduces or even blocks the flow of blood and oxygen that your heart needs, which can lead to:

Your HDL — the happy kind of cholesterol — does its best to save the day. “It goes around your body like a little vacuum cleaner, sucking out cholesterol from the blood vessels,” Dr. Cho explains.

It’s a little confusing that the good stuff and the bad stuff have such similar names. But try to remember that your happy cholesterol tries to clear a path so that your lousy cholesterol can’t cause harm to your body.

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What are normal HDL and LDL levels?

Now that you know about these two types of cholesterol, here’s something else to keep in mind: When you hear about high and low cholesterol (as in high-cholesterol foods or ways to lower your cholesterol), those terms almost always refer to LDL, or the bad cholesterol.

To keep your body at its best, you want to have high levels of HDL and low levels of LDL. Think about it: You don’t want too much of the bad cholesterol, and you want high enough levels of the good cholesterol that it can do its job fighting off the bad stuff.

So, where should your cholesterol levels be? Dr. Cho weighs in.

HDL levels

Ideally, you want your good cholesterol levels to be at 60 mg/dL (milligrams per deciliter) or higher, though a standard range is 40 mg/dL to 59 mg/dL. When your HDL levels fall below 40, you’re at an increased risk for heart disease.

In rare cases, you may have very high levels of HDL that isn’t doing what it should be. “Some people have dysfunctional HDL,” Dr. Cho explains. “In this case, you have very high levels of good cholesterol, but it essentially goes around your body and does nothing.”

LDL levels

It’s important to keep this number low to reduce the risk of various health concerns associated with high cholesterol. And the sooner you start keeping an eye on this number, the better — one study shows that having high cholesterol from an early age increases your risks.

“When we’re born, our bad cholesterol is somewhere around 10, and as we get older, it continues to go up,” Dr. Cho. “When we look at epidemiological and genetic studies, we see that people with very high levels of LDL often go on to have heart attacks and strokes.”

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Ideal LDL levels vary based on your age, sex and health conditions, but for the most part, here’s what to aim for:

  • If you don’t have heart disease: The optimal LDL number is 100 mg/dL or less.
  • If you have or are at high risk for heart disease: If you have heart or blood vessel disease and are at a very high risk (like if you have metabolic syndrome), your healthcare provider will want your LDL level to be even lower — 70 mg/dL or less.

How is cholesterol tested?

A lipid panel is a blood test that measures your total cholesterol and breaks you’re your good and bad cholesterol levels (along with your triglycerides, another important piece of the cholesterol puzzle). In some cases, you’ll need to fast for 10 to 12 hours before this type of test, but non-fasting testing options are now increasingly available.

“It’s a simple, routine blood test,” Dr. Cho says. “A lot of people even get this type of blood test done at job screening health fairs.”

Your cholesterol levels should be tested every five years or so, starting at age 20. But if you’re considered high risk for heart disease or have other relevant health conditions, your doctor will want to test your levels more often.

How to raise good cholesterol and lower bad cholesterol

There are lots of things you can do to better your cholesterol numbers.

  • Diet: Adopt a heart-healthy eating style by focusing on good fats, increasing your fiber intake and scaling back your red meat consumption. Cutting out trans fats goes a long way.
  • Exercise: Say goodbye to a sedentary lifestyle and try to get 30 minutes of moderate to high-intensity exercise at least five days a week.
  • LDL-lowering medications: If natural efforts don’t work, your doctor can prescribe medication to help get your cholesterol numbers where they should be.

To learn more from Dr. Cho about good and bad cholesterol, listen to our Health Essentials Podcast episode, “How to Lower Your Cholesterol.” New episodes of our Health Essentials Podcast publish every Wednesday.

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