Cholesterol is a soft, waxy, fatlike substance found in every body cell and in the bloodstream. It helps to form cell membranes and some important hormones and helps the body digest and absorb fat.
Your liver and other cells make 75% of the cholesterol in your body, according to the American Heart Association (AHA). That's as much as your body needs.
Excess cholesterol, the additional 25%, comes from the foods you eat. When the body has more cholesterol than it can use, the excess circulates in the bloodstream and may start building up inside arteries.
High levels of blood cholesterol are a major risk factor for heart disease, the leading cause of death for American men and women. When cholesterol builds up on artery walls, it makes arteries narrower and stiffer, making it more difficult for blood to get through. Narrowed arteries can block blood flow to the heart entirely, causing a heart attack.
There are two types of cholesterol. HDL (high-density lipoprotein) cholesterol carries excess cholesterol from the bloodstream back to the liver, where it is reprocessed or removed from the body. This artery-cleaning ability is the reason HDL is called good cholesterol. The more HDL cholesterol in your blood, the better.
LDL (low-density lipoprotein) is referred to as bad cholesterol. If too much LDL cholesterol circulates in your blood, it can start sticking to artery and blood vessel walls, causing artery disease and increasing the risk of heart attack and stroke.
According to the AHA, cholesterol levels are evaluated in context with your other risk factors. When you have your cholesterol checked, ask your doctor what your levels mean and if you should have a cholesterol goal. Ask about other risk factors you may need to watch out for because of your cholesterol levels.
High blood cholesterol has no symptoms, so the only way to find out if you have it is to get a blood cholesterol test. All adults ages 20 and older should have a cholesterol test every four to six years.
The National Heart, Lung, and Blood Institute recommends a test called a lipid panel. This test provides information about levels of total cholesterol, LDL, HDL and triglycerides (another form of fat in the blood).
Based on these numbers and any other risk factors, your doctor can tell you what treatments, if any, are needed.
A healthy lifestyle is the best protection against high blood cholesterol. This means getting regular exercise, not smoking and choosing a heart-healthy diet.
According to the AHA, a heart-healthy diet is one that's rich in a variety of fruits, vegetables and whole grains and includes low-fat sources of protein and calcium. You should also limit foods high in saturated fat and trans fats, such as fatty meats, full-fat dairy products, commercially baked goods, fried food and fast food. When in doubt, check the Nutrition Facts label. It provides information about saturated fat and trans fat content.
If your cholesterol remains high when you live by these guidelines, your doctor may recommend medicine to lower cholesterol levels.
To learn more about cholesterol, visit our Cholesterol health topic center. You can also learn more at these websites: