乌鸦传媒

Cholesterol is a waxy substance with many different roles in the body, ranging from helping form cell walls to providing the material to make hormones. This type of lipid is made by the liver and consumed in food you eat.

High density lipoprotein (HDL) cholesterol has the reputation as "good cholesterol," because it takes cholesterol from food and from blood vessels and other parts of the body back to the liver for disposal. It has been associated with lower risk for disease that arises from cholesterol deposits in the blood vessels, called atherosclerosis. These deposits can create blockages and scar the vessel walls, leading to heart disease, heart attacks, stroke, and other health problems.

Low density lipoprotein (LDL) cholesterol accounts for most of the cholesterol in the blood, while very low-density lipoprotein (VLDL) is the main carrier for triglycerides, another type of lipid that stores energy, helps insulate cells, and aids in the absorption of fat-soluble vitamins. Both of these types contribute to atherosclerosis; you may see them grouped together on your blood test results as "non–HDL cholesterol."

An initial blood test to measure your cholesterol may be done whether you have fasted from food or not; but because food can change your blood cholesterol levels, more precise measurements require fasting.

What is considered too much cholesterol depends on your health. For most people, HDL cholesterol should ideally be above 60 milligrams per deciliter of blood (mg/dL), LDL should be below 100 mg/dL, and total cholesterol should be below 200 mg/dL. But LDL is best kept below 100 mg/dL for people who have type 2 diabetes and below 70 mg/dL for those who have coronary artery disease -- including a history of heart attacks, angina, stents, or coronary bypass.

Levels above these thresholds will be diagnosed as hypercholesterolemia.

Very high LDL cholesterol (190 mg/dL and above) may indicate a genetic condition, called familial hypercholesterolemia, that strongly increases heart risk and must be treated intensively.

"Medical Journeys" is a set of clinical resources reviewed by doctors, meant for physicians and other healthcare professionals as well as the patients they serve. Each episode of this journey through a disease state contains both a physician guide and a downloadable/printable patient resource. "Medical Journeys" chart a path each step of the way for physicians and patients and provide continual resources and support, as the caregiver team navigates the course of a disease.