What Is HDL Cholesterol? - Definition & Healthy Levels

Instructor: Amanda Robb

Amanda holds a Masters in Science from Tufts Medical School in Cellular and Molecular Physiology. She has taught high school Biology and Physics for 8 years.

In this lesson we'll explain what HDL cholesterol is and how it affects the body. We'll also look at the healthy range for HDL and the factors that can increase HDL levels.

What Is Cholesterol?

Although we usually think of cholesterol as something clogging our arteries and causing major problems for our hearts, there is actually another type of cholesterol that is good for your heart. This cholesterol is called high-density lipoprotein, or HDL. Cholesterol is a steroid lipid, a ring of carbon atoms, found in all your cells and your blood stream.

Molecular structure of cholesterol

Cholesterol is transported in lipoproteins, small spheres composed of cholesterol, other fats called phospholipids and triglycerides, and protein. HDL has different proteins on the surface of the sphere compared to the 'bad' cholesterol lipoproteins (LDL) that are associated with heart disease. The proteins in HDL allow it to pick up the bad cholesterol and clear it from the body. HDL cholesterol is more dense; it contains more protein and less cholesterol compared to LDL, hence the name 'high-density lipoprotein'.

Structural diagram of HDL cholesterol
HDL diagram

What Is HDL?

HDL is 'good cholesterol' and can help control the levels of 'bad cholesterol' (LDL) floating around in your blood. HDL moves through your blood and picks up LDL cholesterol along the way. It then delivers it to the liver where it can be broken down into other compounds our body can use.

LDL (in yellow) causes arteries to clog whereas HDL (in blue) helps clear arteries of LDL
cholesterol types

Think of this process as being like a garbage pickup service. The HDL is the garbage men who pick up trash around the city. They take what they collect to a recycling plant, where it can be broken down and made into something useful. Some people with high cholesterol can't lower their LDL enough on their own to prevent heart disease. These patients also need high HDL levels to protect their blood vessels. Doctors might prescribe foods that raise HDL levels to achieve this.

Now, let's consider the levels of HDL doctors are looking for when checking your cholesterol.

Healthy HDL Levels

Cholesterol is measured in milligrams (mg) per deciliter (dL) of blood. One deciliter is equal to a little over two measuring cups of liquid. One milligram of HDL is equal to about 0.0002 teaspoons. When you go to the doctor, they will measure your total cholesterol levels, as well as the LDL levels and the HDL levels. Your total cholesterol levels should be no greater than 200mg/dL. The greater the percentage of HDL that makes up your total cholesterol the better. Doctors recommend that people have HDL levels near 60mg/dL. Below 40mg/dL for men is considered a risk factor for heart disease. Women need a little more, about 50mg/dL.

How to Increase HDL Levels

At this point you might be wondering what your own HDL levels are and how to boost them. The best way to find out is to go to a doctor and have your cholesterol checked. If your HDL levels are low, your doctor might suggest changing your diet and behavior, or even taking a specific medication to help.


Healthy fats found in nuts, nut or olive oils, avocados, and fish containing omega-3 fats support production of HDL. Including these foods in your diet in moderation can raise your HDL levels. But remember, too much fat isn't good either. Doctors recommend only about 25 to 30 grams of fat per day. If these fats come mostly from the healthy fats mentioned above, you're on the right track!

Avocados are a healthy fat that can raise HDL levels


Diet, however, is only one piece of the puzzle. Increasing your amount of exercise can also boost HDL. About 30 minutes of brisk exercise five times a week helps protect your heart and increase HDL. We all know smoking is bad for us too, but the consequences extend beyond lung cancer. Smoking actually decreases your HDL, so cutting that bad habit can help increase levels of HDL as well. Losing weight will also help. Making the diet changes needed to increase your HDL will definitely help with this lifestyle change too.

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