Sitosterols: A family of sterols commonly found in plants and plant oils. Alpha-, beta-, and gamma-isomers have been characterized.Phytosterols: A class of organic compounds known as STEROLS or STEROIDS derived from plants.StigmasterolCholestanol: A cholesterol derivative found in human feces, gallstones, eggs, and other biological matter.Sterols: Steroids with a hydroxyl group at C-3 and most of the skeleton of cholestane. Additional carbon atoms may be present in the side chain. (IUPAC Steroid Nomenclature, 1987)Xanthomatosis: A condition marked by the development of widespread xanthomas, yellow tumor-like structures filled with lipid deposits. Xanthomas can be found in a variety of tissues including the SKIN; TENDONS; joints of KNEES and ELBOWS. Xanthomatosis is associated with disturbance of LIPID METABOLISM and formation of FOAM CELLS.Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Desmosterol: An intermediate in the synthesis of cholesterol.Cholestanes: Derivatives of the saturated steroid cholestane with methyl groups at C-18 and C-19 and an iso-octyl side chain at C-17.Absorption: The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.Intestinal Absorption: Uptake of substances through the lining of the INTESTINES.Lymphatic System: A system of organs and tissues that process and transport immune cells and LYMPH.Bile: An emulsifying agent produced in the LIVER and secreted into the DUODENUM. Its composition includes BILE ACIDS AND SALTS; CHOLESTEROL; and ELECTROLYTES. It aids DIGESTION of fats in the duodenum.SqualeneLipid Metabolism, Inborn Errors: Errors in the metabolism of LIPIDS resulting from inborn genetic MUTATIONS that are heritable.Bile Acids and Salts: Steroid acids and salts. The primary bile acids are derived from cholesterol in the liver and usually conjugated with glycine or taurine. The secondary bile acids are further modified by bacteria in the intestine. They play an important role in the digestion and absorption of fat. They have also been used pharmacologically, especially in the treatment of gallstones.Margarine: A butterlike product made of refined vegetable oils, sometimes blended with animal fats, and emulsified usually with water or milk. It is used as a butter substitute. (From Random House Unabridged Dictionary, 2d ed)EstersThoracic Duct: The largest lymphatic vessel that passes through the chest and drains into the SUBCLAVIAN VEIN.Esterification: The process of converting an acid into an alkyl or aryl derivative. Most frequently the process consists of the reaction of an acid with an alcohol in the presence of a trace of mineral acid as catalyst or the reaction of an acyl chloride with an alcohol. Esterification can also be accomplished by enzymatic processes.Sterol O-Acyltransferase: An enzyme that catalyzes the formation of cholesterol esters by the direct transfer of the fatty acid group from a fatty acyl CoA derivative. This enzyme has been found in the adrenal gland, gonads, liver, intestinal mucosa, and aorta of many mammalian species. EC 2.3.1.26.AzetidinesCholesterol, Dietary: Cholesterol present in food, especially in animal products.ATP-Binding Cassette Transporters: A family of MEMBRANE TRANSPORT PROTEINS that require ATP hydrolysis for the transport of substrates across membranes. The protein family derives its name from the ATP-binding domain found on the protein.Lipoproteins: Lipid-protein complexes involved in the transportation and metabolism of lipids in the body. They are spherical particles consisting of a hydrophobic core of TRIGLYCERIDES and CHOLESTEROL ESTERS surrounded by a layer of hydrophilic free CHOLESTEROL; PHOSPHOLIPIDS; and APOLIPOPROTEINS. Lipoproteins are classified by their varying buoyant density and sizes.Hypercholesterolemia: A condition with abnormally high levels of CHOLESTEROL in the blood. It is defined as a cholesterol value exceeding the 95th percentile for the population.Chromatography, Gas: Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.Anticholesteremic Agents: Substances used to lower plasma CHOLESTEROL levels.Cyclodextrins: A homologous group of cyclic GLUCANS consisting of alpha-1,4 bound glucose units obtained by the action of cyclodextrin glucanotransferase on starch or similar substrates. The enzyme is produced by certain species of Bacillus. Cyclodextrins form inclusion complexes with a wide variety of substances.Micelles: Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.