What Is HDL (High-Density Lipoprotein)?

By HelloLife

When doctors evaluate a person's cholesterol levels they usually look at two major kinds: LDL (low-density lipoprotein) and HDL (high-density lipoprotein). So what do these protein-things have to do with your cholesterol? Which one is considered to be bad? Which one is considered to be good? And how does someone increase good cholesterol and lower the bad? For the answers to these questions and many more, read on.

HDL and LDL: Comedy and Tragedy

To remember which cholesterol is the good one and which is the bad, think of healthy and lousy. HDL cholesterol is the good kind, the kind that can keep you healthy. It functions by taking excess cholesterol from the arteries and returning it to the liver for excretion. LDL cholesterol - while necessary for proper function - can be lousy in large amounts. It brings cholesterol from the liver out to arteries where it can be used to make cell membranes. In excess, LDL causes atherosclerosis which can lead to heart disease and stroke.

Lipoprotein-What?

Cholesterol is waxy-like substance that is used to create hormones and cell membranes. The liver creates about 75% of the cholesterol needed by the body while the other 25% (or more in some cases) comes from the foods we eat. Much like oil doesn't dissolve in water, cholesterol doesn't dissolve in blood. So in order to efficiently move cholesterol throughout the body, protein carriers are needed. The combination of a fat (like cholesterol) and a protein is called a lipoprotein.

The Dangers of High Cholesterol

It's a good idea to keep track of your cholesterol level, especially as you age. High levels of cholesterol, which actually refers to high bad cholesterol, i.e. LDL, can accelerate the development of the condition known as atherosclerosis, where arteries become hardened with cholesterol build-up. Severe atherosclerosis can cause arteries to become dangerously narrowed. High cholesterol levels can also increase the chances of a fat embolus (or clot) developing, which can then get stuck in narrowed arteries and prevent blood flow to vital organs like the heart and brain, causing heart attacks or strokes.

Testing HDL Levels

When doctors test for cholesterol levels, they do what is called a lipid profile test. This is performed by taking a blood sample and analyzing it for total cholesterol, LDL content, HDL content, and triglyceride (another fat produced by the body) content. Because HDL is the healthy cholesterol, the more of it there is the better. A test result of 40 mg/dL or higher is considered healthy, whereas a result of 40 mg/dL or lower increases the risk for heart disease. High HDL (60 mg/dL or higher) is actually considered a negative risk factor, meaning it can greatly decrease your risk of heart disease.

Lowering LDL and Raising HDL

While there are several ways to lower LDL (diet, exercise, and weight loss) there aren't so many options for raising HDL levels. Sometimes medications which lower LDL can also increase HDL, but this isn't always the case. Smoking is known to decrease HDL, so quitting the habit is certainly one fool-proof method for increasing HDL. Regular exercise has also been shown to increase HDL levels. When diet and exercise aren't enough to adequately lower your LDL levels, look to the many natural methods that have been shown to lower cholesterol.

Sources:

http://www.americanheart.org/presenter.jhtml?identifier=180

http://www.kidshealth.org/parent/medical/heart/cholesterol.html

http://labtestsonline.org/understanding/analytes/hdl/glance.html

Photo Credit: Diet Chef