What Is Oxidized Cholesterol?

Definition, Effects, Food Sources, and Ways to Prevent Future Buildup

Oxidized cholesterol is made in the body when low-density lipoprotein (LDL), sometimes called “bad” cholesterol, goes through a chemical reaction. Oxidized cholesterol is what builds up on the artery walls, the muscular tubes that carry blood away from the heart.

Too much oxidized cholesterol can lead to atherosclerosis, or hardening of the arteries. The resulting decrease in blood flow in your arteries raises your risk for heart attack and stroke. 

What is cholesterol?

Cholesterol is a waxy substance in the blood, one of a group of non-water-soluble molecules called lipids. Cholesterol is used to build healthy cells in the body, which help with bodily structure, nutrient processing, and making energy.

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This article explains what oxidized cholesterol is, what causes it, and how it can impact your overall health. It will also discuss what can help reduce and prevent oxidized LDL buildup.

What Causes LDL to Oxidize?

LDL cholesterol can buildup due to:

When LDL cholesterol reacts with free radicals (unstable molecules made during normal cell metabolism), it can become oxidized. While oxidation is a normal process, it is possible for your body to make too much oxidized cholesterol. This can lead to inflammation and other health concerns.

LDL cholesterol molecules are not all the same size. Smaller LDL particles are more likely to become oxidized, making them more dangerous to your health.

What Are The Effects of Oxidized LDL?

Oxidized LDL can cause inflammation in the arteries. Platelets, which normally help to stop bleeding by producing blood clots, can stick to areas of inflammation within the arteries. When they do, they create sticky, hardened areas inside blood vessels called plaques.

Over time, fat, cholesterol, and other substances build up in the walls of the arteries. This causes the plaques to grow.

Plaque buildup can partially or completely block blood flow within an artery. This is referred to as atherosclerosis.

Atherosclerosis increases a person’s risk for:

While research has largely indicated that oxidized LDL cholesterol has a negative effect on the body, some studies suggest mild oxidation of LDL may have some protective factors.

How Do You Reduce Oxidized LDL?

You can test for cholesterol levels through routine cholesterol blood tests. These determine levels of LDL, HDL, and triglycerides, or a type of fat in the blood. Routine cholesterol tests do not measure the concentration of small versus large LDL molecules or oxidized LDL levels, though advanced lipoprotein tests can measure these.

If you have elevated or high cholesterol, lifestyle changes can help you reduce your level of small LDL. This can help prevent the formation of oxidized LDL.

According to the American Heart Association (AHA), cholesterol testing should be done every four to six years for people age 20 or older who are at low risk for cardiovascular disease. People with cardiovascular risk factors may need more frequent testing.

LDL cholesterol levels should be less than 100 mg/dL.

What Foods Remove Oxidized Cholesterol?

What you eat can play a significant role in preventing oxidized LDL.

Oxidized cholesterol-lowering foods include:

  • Fruits and vegetables: Produce is rich in antioxidants with natural anti-inflammatory properties that may help reduce the oxidation of LDL.
  • Healthy fats: Healthy fats, like those in nuts, avocados, and seafood, help raise HDL. This is believed to have an antioxidant effect because of its ability to neutralize an enzyme that plays a role in oxidation.


Antioxidants are substances that help prevent oxidation and reduce or slow cell damage.

Foods That Cause Oxidized Cholesterol

Foods that cause oxidized cholesterol that should be limited or avoided include:

  • Trans fats: Foods higher in trans fats include pastries, deep-fried foods, potato chips, and any food cooked with lard.
  • Sugary foods: Refined sugars have been linked to higher levels of oxidized cholesterol.

Natural sugars, like those found in fruits, have not been shown to increase cholesterol.

What Else Can Help Reduce Oxidized LDL?

You can further boost your efforts to prevent oxidized cholesterol by:

  • Quitting or avoiding smoking. Smoking exposes you to chemicals that promote free radical formation, increasing oxidative damage.
  • Controlling your blood sugar. If you have been diagnosed with diabetes, a group of conditions that impact blood sugar, or metabolic syndrome, a group of conditions that increase your risk of stroke, heart disease, and diabetes, it’s important to keep your sugar levels in check. In some cases, your healthcare provider may prescribe medication.
  • Exercising. Regular physical activity can help raise HDL, or the “good” cholesterol.

Some cholesterol-lowering medications, such as statins, also have anti-inflammatory properties that may help prevent the inflammation that promotes plaque buildup in the arteries.

At normal levels, LDL and HDL cholesterol do not cause problems.


Oxidized cholesterol forms in the body when LDL goes through a chemical reaction. Oxidized LDL can build up on the artery walls due to eating certain foods high in trans fats. Smoking tobacco products is also linked to high levels of oxidized LDL.

Oxidized LDL can lead to inflammation in the arteries and eventually atherosclerosis, which is linked to other serious health concerns.

A Word From Verywell

Oxidized LDL is increasingly recognized as a contributor to heart disease, vascular disease, and stroke.

If you’ve been diagnosed with elevated or high cholesterol, taking steps to eat healthier, exercise more, and to stop smoking can help. A lower level of LDL decreases the chance of plaque buildup. Speak with your healthcare provider about ways you can prevent or reduce LDL buildup.

Frequently Asked Questions

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  9. DiNicolantonio JJ, Lucan SC, James H. O’Keefe JH. The evidence for saturated fat and for sugar related to coronary heart diseaseProg Cardiovasc Dis. 2016;58(5):464-472. doi:10.1016/j.pcad.2015.11.006

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By Jennifer Moll, PharmD
Jennifer Moll, MS, PharmD, is a pharmacist actively involved in educating patients about the importance of heart disease prevention.