How High Cholesterol Leads to Atherosclerosis

High cholesterol levels can lead to clogged arteries that come from a process known as atherosclerosis or hardening of the arteries. Having the right level of cholesterol helps lower the risk of problems caused by clogged arteries. That includes heart attacks and strokes.

But what makes cholesterol so bad for you? And how does treating high cholesterol help?

Cholesterol and Atherosclerosis: The Bad and the Good

Cholesterol is a kind of fat found in your blood. Your liver makes it because cells and certain organs need it. Your body also gets cholesterol from some of the foods you eat. But if your body gets too much, the cholesterol can do serious damage, especially inside your arteries.

Some people think that all cholesterol is “bad.” But there are different kinds of cholesterol, and too much of one kind certainly is bad. But there’s another kind of cholesterol that is “good” because it helps keep your body well.

The "bad" cholesterol is called LDL or low-density lipoprotein. LDL can damage your arteries that carry blood from your heart to the rest of your body. Then once the damage has started, LDL keeps on penetrating and building up in the artery walls.

As the deposits grow, your body tries to clean them up. White blood cells and other kinds of cells that are part of your body’s defense attack the buildup and chew it up. But over time, those cells and the resulting debris become part of the buildup. Over years, the deposits grow larger and form what’s called plaque.

The "good" cholesterol is known as HDL or high-density lipoprotein. HDL circulates through your body, acting like a cholesterol magnet. It gathers up the bad cholesterol and moves it out of your arteries. Eventually, much of the cholesterol is either eliminated from your body, delivered to tissues such as the liver, or used to make hormones.

As plaques grow inside your arteries, they eventually start to block the flow of blood. Some LDL-rich plaques grow in a slow, controlled way. While they may eventually narrow arteries enough to cause symptoms, the body generally adapts. And this type of blockage seldom causes heart attacks.


But other plaques are unstable. The white blood cells and other cells the body sends to consume the plaque also release enzymes. These enzymes dissolve some of the tissue called collagen that holds the plaque together. When that happens, the plaque deposit can rupture. Then the debris from it can cause a blood clot to form inside the artery. Sometimes, within minutes, this clot can cut off the blood that goes to the heart or the brain and cause a heart attack or stroke.

Cholesterol Treatment: Down With the Bad, Up With the Good

As your cholesterol level gets higher, so does the likelihood that more plaques will form. The link between cholesterol and life threatening events makes treating high cholesterol a priority. Both medications and changes in lifestyle can improve cholesterol level and reduce the risks that come with atherosclerosis:

  • Exercise with or without weight loss increases "good" HDL cholesterol and reduces the risk of heart attacks and strokes.
  • A diet high in fiber and low in fats can lower "bad" LDL cholesterol.
  • Oily fish and other foods high in omega 3 fatty acids can raise “good” HDL cholesterol.
  • Statins are the medicines most-often prescribed for high cholesterol. They can dramatically lower "bad" LDL cholesterol, by up to 60% or more. They can also increase HDL.

Studies have shown that statins can reduce the rates of heart attacks, strokes, and death from atherosclerosis. But to be effective, statins need to be part of a larger personalized strategy you and your doctor work out together. Among other things, that strategy will be based on your level of risk for heart attack and stroke as well as your own personal life-style choices.

If you know or think your cholesterol is high or if you have a family history of high cholesterol, talk to your doctor about ways you can lower it.


WebMD Medical Reference Reviewed by James Beckerman, MD, FACC on July 17, 2020



American Heart Association: "What is Atherosclerosis?"

American Heart Association: "LDL and HDL Cholesterol: What's Bad and What's Good?" 

Brown, L. American Journal of Clinical Nutrition, 1999. 

Rosenson, R. Expert Review of Cardiovascular Therapy, 2003. 

Richard Stein, MD, national spokesperson, American Heart Association; professor of medicine and director of urban community cardiology program, New York University School of Medicine, New York.

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