High Cholesterol Make an Appointment Find a Doctor Ask a Question Reviewed by Howard D. Weinberger, MD, FACC (July 01, 2019) Blood transports necessary nutrients, fuel and oxygen to your body. Cholesterol is a type of fat in the blood. Some cholesterol is important for your body’s function. High levels of cholesterol in the blood (high blood cholesterol) can be serious. It can cause fatty deposits, called plaque, to build up in arteries, making blood flow more difficult. High blood cholesterol can be secondary to many diseases. It can also contribute too many forms of disease, most notably cardiovascular disease, or heart disease. There are often no signs or symptoms of high blood cholesterol. Many people don't know that their cholesterol level is too high until they have a heart attack or stroke, unless they have their cholesterol levels checked regularly. Everyone age 20 and older should have their cholesterol levels checked at least once every five years. You and your doctor can discuss how often you should be tested. Programs & Services Cardiology Programs Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.