The Causes and Effects of Oxidized LDL Cholesterol

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Oxidized low-density lipoprotein (LDL) is a potentially harmful type of cholesterol that is produced in the body when normal LDL cholesterol is damaged by chemical interactions with free radicals.

Together with inflammatory responses, free radicals can result in hardening of the arteries (atherosclerosis). The resulting decrease in blood flow in your arteries increases your chances of having a heart attack or a stroke.

You can produce high levels of oxidized LDL if you have excessive free radical formation or simply high LDL cholesterol levels. 

How Oxidized LDL Forms

The oxidation of LDL is thought to occur when LDL cholesterol particles in your body react with free radicals; unstable molecules that are produced as a result of normal metabolism, a disease, or exposure to toxins.

Free radicals cause oxidation, a type of chemical destabilization of molecules such as LDL cholesterol. The oxidized LDL itself then becomes more reactive with the surrounding tissues, which can produce inflammation that leads to disease and organ damage. In particular, oxidized LDL is a threat to your cardiovascular health.

LDL cholesterol molecules are not all the same size, and some are larger than others. Smaller LDL particles are more likely to become oxidized, making them more detrimental to your health.

Some risk factors that appear to increase the levels of oxidized LDL include:

  • Consuming a diet that is high in trans fats
  • Smoking
  • Poorly controlled diabetes
  • Metabolic syndrome, which is often a precursor of diabetes
  • Exposure to toxins through pollution and preservatives
  • Stress

Once LDL becomes oxidized, it inhabits the inner lining (endothelium) of the body's arteries, such as the carotid arteries, the coronary arteries, and arteries that supply blood to your legs and arms.

The Effects of Oxidized LDL

Inflammation in the arteries produced by oxidized LDL causes problems because the vessels it affects carry blood to all of your organs and tissues. Oxidized LDL is thought to promote the development of atherosclerosis, which increases your risk of having a heart attack or a stroke.

LDL cholesterol in the endothelial lining of the arteries promotes the accumulation of white blood cells (lymphocytes), immune cells (dendritic cells), and inflammatory cells (macrophages) in the blood vessels.

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 hardened areas inside a blood vessel called plaques.

Over time, more macrophages, cholesterol, and other lipids begin to accumulate at the site (which is usually sticky) causing the plaques to grow.

Plaque buildup can partially or completely restrict blood flow within an artery, which increases a person's risk for coronary heart disease, peripheral vascular and cerebrovascular disease.

While research has largely indicated that oxidized LDL cholesterol has a negative affect on the body, some preliminary studies have brought interesting new theories into the discussion, such as the potential for oxidized LDL to be protective. 

Prevention

Routine cholesterol blood tests determine levels of LDL, HDL (good cholesterol), and triglycerides, but they do not measure the concentration of small versus large LDL molecules or oxidized LDL levels. 

Lifestyle changes can help you reduce your level of small LDL and prevent the formation of oxidized LDL.

You may be able to reduce and prevent oxidized LDL by:

  • Working to lower your overall LDL cholesterol level. In some cases, you may need medication to do this. Some cholesterol-lowering medications, such as statins, also possess anti-inflammatory properties that may also help prevent the inflammation that promotes atherosclerosis.
  • Quitting (or not starting) smoking. Smoking exposes you to chemicals that promote free radical formation, increasing oxidative damage. 
  • Excluding trans fats from your diet, such as pastries, deep-fried foods, potato chips, and any food cooked with lard.
  • Adding fruits and vegetables to your diet, Produce is rich in antioxidants with natural anti-inflammatory properties that may help to reduce the oxidation of LDL.
  • Keeping your blood sugar level controlled if you have been diagnosed with diabetes or metabolic syndrome. Steps you can take may include losing weight, eating healthy, and exercising. If lifestyle changes alone are not enough to manage your blood sugar levels, your doctor may prescribe medications.
  • Raising your HDL levels. This "good cholesterol" is believed to have an antioxidant effect because of its ability to deactivate lipid hydroperoxide, an enzyme that plays a role in the oxidation of LDL cholesterol. Exercise and eating healthy fats (found in nuts, avocados, and seafood) are associated with optimal HDL levels.

A Word From Verywell

High LDL cholesterol levels can place you at risk for developing cardiovascular disease, and the type of LDL circulating in your blood matters. Oxidized LDL is increasingly recognized as a contributor to heart disease, vascular disease, and stroke.

It is generally not considered helpful to do a specialized test to measure oxidized LDL. Levels of oxidized LDL generally correlate with the presence of other, easily detected risk factors, such as those listed above. Actually measuring oxidized LDL, therefore, usually doesn't add much to your doctor's ability to estimate your overall cardiovascular risk.

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