Medical Dictionary: Cholesterol

High cholesterol affects about 17% of Americans ages 20 and older, contributing to atherosclerotic heart disease, which is the single leading cause of death and disability in the developed world. This medical dictionary covers the terms used in the report, What to do about High Cholesterol, and includes details on how to lower and watch your cholesterol through tests and diets.

antioxidant: A substance that inhibits oxidation.

apolipoproteins: Proteins that combine with cholesterol and triglyceride to form lipoproteins.

atherosclerosis: Development of cholesterol-rich plaque on the inner walls of arteries, which can eventually obstruct blood flow.

atherosclerotic plaque: A cholesterol-rich deposit on an artery wall.

biological variability: Fluctuations that occur naturally over time in the levels of a substance such as cholesterol in a person’s body.

cholesterol: A fatlike substance that is produced by the liver and found in all food from animal sources; an essential component of body cells and a precursor of bile acids and certain hormones.

chylomicron: A large, extremely low-density lipoprotein that transports triglyceride from the intestine to fat tissue in the body.

combined hyperlipidemia: A condition in which LDL and triglyceride levels are very high.

familial combined hyperlipidemia: An inherited disorder in which the liver overproduces VLDL, causing high levels of cholesterol or triglycerides, or both.

familial hypercholesterolemia: An inherited disorder in which the liver cannot properly remove LDL particles from the blood, causing a very high cholesterol level.

fasting lipid profile: A laboratory test to determine the relative levels of HDL, LDL, and total cholesterol in the blood. Also referred to as a lipoprotein analysis, full lipid profile, or cholesterol profile.

fatty acids: The primary building blocks of lipids.

foam cells: Lipid-laden cells, named for their foamy appearance under the microscope, which contribute to the formation of atherosclerotic plaque.

high-density lipoprotein (HDL): A lipoprotein that protects the arteries by transporting cholesterol from body cells to the liver for elimination.

hydrogenation: The addition of hydrogen to a compound, particularly to solidify unsaturated oils.

lipids: Fats, oils, and waxes that serve as building blocks for cells or as energy sources for the body.

lipoproteins: Protein-covered fat particles that enable cholesterol to move easily through the blood.

low-density lipoprotein (LDL): A lipoprotein that transports cholesterol from the liver to the rest of the body, which can cause the buildup of plaque in the arteries.

monounsaturated fats: Fatty acids; abundant in olive, peanut, sesame, and canola oils.

oxidation: A process in which oxygen combines with a substance, altering its structure and changing or destroying its normal function.

platelets: Minute, colorless disks in the blood that are instrumental in clotting.

polyunsaturated fats: Fatty acids that are abundant in soybean, corn, cottonseed, safflower, and sunflower oils.

saturated fats: Fatty acids that are abundant in red meat, lard, butter, cheese, and some vegetable oils, in which each molecule carries the maximum number of hydrogen atoms.

trans fats: Fatty acids (such as those found in solid margarine) that have been reshaped by hydrogenation; also called trans fatty acids.

triglyceride: The primary type of fat in the body and in the diet, formed from three fatty-acid molecules and one glycerol molecule.

unsaturated fats: Fatty acids in which some of the hydrogen atoms in each molecule have been replaced by double bonds; includes monounsaturated and polyunsaturated fats.

very-low-density lipoprotein (VLDL): A lipoprotein that transports triglyceride manufactured in the liver to fat tissue in the body; eventually becomes low-density lipoprotein (LDL) after the triglyceride has been removed.