Cholesterol is a type of fat, also known as a lipid, that circulates in your blood. It is naturally produced by your body and performs a number of important functions. For example, it helps build cell membranes; aids in the production of hormones, including estrogen and testosterone; and is critical to the process of fat absorption from food. Too much blood cholesterol can lead to artery damage and cardiovascular disease.

Cholesterol comes from two sources:

  • The foods you eat, which provide 15% to 20%
  • Your liver, which produces 80% to 85%

When your cholesterol levels are higher than normal, you’re considered to have “high cholesterol,” which is also known as “hyperlipidemia” or “hypercholesterolemia.” High blood cholesterol strongly increase your chances of having a heart attack or developing cardiovascular disease, it also puts you at greater risk for other serious health problems, such as the following:

  • Coronary artery disease
  • Stroke
  • High blood pressure
  • Diabetes
  • Obesity

Cholesterol is carried in the body by particles called lipoproteins — a type of cholesterol. There are three main components of cholesterol you should know about:

  • LDL (low-density lipoprotein): Sometimes called “bad” or “lousy” cholesterol, LDL carries most of the cholesterol in the blood to be stored away for future use. High levels of LDL cause cholesterol to build up on artery walls, leading to plaque formation.

When LDL is too high

Too much LDL can lead to a buildup of cholesterol (plaques) on the walls of blood vessels, causing them to narrow or harden and restrict blood flow. This is known as atherosclerosis.

Narrowing of the blood vessels that lead to the heart can cause coronary artery disease, angina, and heart attack. Heart attacks result when plaques rupture, breaking away from the wall of a blood vessel, and block an artery. Narrowing of the blood vessels leading to the brain can cause stroke.

  • HDL (high-density lipoprotein): Called “good” or “healthy” cholesterol, HDL carries cholesterol from the body to the liver, where it is eliminated. The more HDL you have in your blood, the better protected you are against the buildup of plaque in your arteries.

When HDL is too low

When your HDL cholesterol is too low, harmful cholesterol stays in the arteries instead of being transported to the liver and ultimately eliminated from the body.

  • Triglycerides (TC): This is the most common type of fat in your body. Triglycerides have a dual function, acting to both store and transport fat in the blood. When you eat excess calories (especially sugar and alcohol), they are stored as triglycerides. Similar to LDLs, excess triglycerides increase your risk for cardiovascular disease.

When triglycerides are too high

High triglyceride levels are dangerous to your cardiovascular health because they increase the likelihood of hardening of the arteries, which raises the risk for heart disease, stroke, and heart attack.

Total cholesterol/HDL (TC/HDL) is a ratio used to measure your cardiovascular risk. TC/HDL is calculated by dividing your total cholesterol number by your total HDL cholesterol number.


Cholesterol levels generally are lower in younger women than younger men, but above the age of 65 they are much higher in women. If you have high levels of LDL cholesterol, your doctor may prescribe cholesterol-lowering medication, changes to your diet and exercise.

However, no matter your gender, age, or ethnicity, you are at risk for high cholesterol.

The following factors may put you at increased risk for high cholesterol. If one or more of these applies to you, see your doctor to have your cholesterol tested:

  • You’re a man 40 years or older.
  • You’re a woman 50 years or older or are past menopause.
  • You have a first-degree relative younger than age 60 who died of cardiovascular disease.
  • You’ve experienced a previous heart attack or stroke.
  • You have diabetes.
  • You have high blood pressure.
  • You have kidney disease.
  • You smoke.
  • You’re obese*.
  • You have an inflammatory disease.
  • You have HIV.

*Obesity is indicated as a waist circumference of more than 102 cm (40 in) for men or in excess of 88 cm (35 in) for women. For people of Chinese or South Asian descent, a waist size of more than 90 cm (35 in) for men or in excess of 80 cm (32 in) for women indicates obesity.


Some causes of high cholesterol are beyond your control. High cholesterol can be hereditary, and levels of LDL naturally rise as people get older. Your cholesterol is also influenced by these unchangeable factors:

  • Age
  • Family history
  • Gender (risk increases in post-menopausal women)

There are factors, or habits, you can change that negatively impact your cholesterol. These include:


There are no symptoms for high cholesterol. Many people with high cholesterol are not aware their levels are high, putting them at risk for cardiovascular disease.