How Cholesterol Affects Your Heart's Health

When most people hear "cholesterol" they think "evil." Like most things in life, the reality is more complex; cholesterol can be very bad and very good. On its own, cholesterol is a crucial body component. That's why you make the white, waxy substance (about 75% of the cholesterol in your blood is made by the liver and cells elsewhere in your body). Cholesterol insulates nerve cells in your brain and provides structure for cell membranes.

"If you want to see what it looks like in a solidified form, go get yourself a can of Crisco at the grocery store," says Gregory Dehmer, MD, director of the division of cardiology at the Texas A&M College of Medicine. "If you open up a can of Crisco, it’s this white, lard-like substance."

When it comes to heart disease, though, some types of cholesterol are too much of a good thing.

How cholesterol can clog arteries
Not all cholesterol is created equal. It's a fatty substance, so cholesterol can't dissolve in the blood to be carried to where it's needed in the body. "Your body is mostly water, and fat and water don't mix," says Dr. Dehmer.

So cholesterol is packaged into proteins that can shuttle the fatty stuff around your body. One is high-density lipoprotein (HDL, or good cholesterol) and another is low-density lipoprotein (LDL, or bad cholesterol).

What's the difference? LDL can stick to the smooth lining of the blood vessels, where it is absorbed. HDL appears to do the opposite—it actually mops up excess cholesterol and removes it from the blood vessels.