Benjamin Wedro, MD, FACEP, FAAEM
Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Cholesterol levels facts
- What is cholesterol?
- What are LDL and HDL cholesterol?
- What determines the level of LDL cholesterol in the blood?
- Does lowering LDL cholesterol prevent heart attacks and strokes?
- How can LDL cholesterol levels be lowered?
- What are "normal" cholesterol blood levels?
- What are the 2013 ACC/AHA Guidelines?
- Why is HDL the good cholesterol?
- What are LDL/HDL and total/HDL ratios?
- How can levels of HDL cholesterol be increased?
- What are triglycerides and VLDL?
- Do high triglyceride levels cause atherosclerosis?
- What causes elevated triglyceride levels?
- How can elevated blood triglyceride levels be treated?
- What are cholesterol-lowering foods?
- What medications are available to lower cholesterol, lipids, and triglycerides?
- Is lowering LDL cholesterol enough?
What is cholesterol?
Cholesterol is a chemical compound that is naturally produced by the body and is structurally a combination of fat (lipid) and steroid. Cholesterol is a building block for cell membranes and for hormones like estrogen and testosterone. About 80% of the body's cholesterol is produced by the liver, while the rest comes from our diet. The main sources of dietary cholesterol are meat, poultry, fish, and dairy products. Organ meats, such as liver, are especially high in cholesterol content, while foods of plant origin contain no cholesterol. After a meal, dietary cholesterol is absorbed from the intestine and stored in the liver. The liver is able to regulate cholesterol levels in the bloodstream and can secrete cholesterol if it is needed by the body.
What are LDL and HDL cholesterol?
LDL cholesterol is called "bad" cholesterol, because elevated levels of LDL cholesterol are associated with an increased risk of coronary heart disease, stroke, and peripheral artery disease. LDL lipoprotein deposits cholesterol along the inside of artery walls, causing the formation of a hard, thick substance called cholesterol plaque. Over time, cholesterol plaque causes thickening of the artery walls and narrowing of the arteries, a process called atherosclerosis, which decreases blood flow through the narrowed plaque-filled vessel. In the heart, narrowing of its blood vessels may lead to angina or heart attack. In the brain this may cause a transient ischemic attack (TIA) or stroke.
HDL cholesterol is called the "good cholesterol" because HDL cholesterol particles prevent atherosclerosis by extracting cholesterol from the artery walls and disposing of them through the liver. Thus, high levels of LDL cholesterol and low levels of HDL cholesterol (high LDL/HDL ratios) are risk factors for atherosclerosis, while low levels of LDL cholesterol and high levels of HDL cholesterol (low LDL/HDL ratios) are desirable and protect against heart disease and stroke.
Total cholesterol is the sum of LDL (low density) cholesterol, HDL (high density) cholesterol, VLDL (very low-density) cholesterol, and IDL (intermediate density) cholesterol.
Tips to keep it under control.