Lipid

Lipids are a diverse group of organic compounds characterized by their insolubility in water and solubility in nonpolar solvents. They include fats, oils, waxes, sterols (such as cholesterol), fat-soluble vitamins (A, D, E, K), phospholipids, sphingolipids, and more. Lipids are primarily composed of carbon, hydrogen, and oxygen. Many lipids are amphipathic: they contain both hydrophobic and hydrophilic regions. Lipids play roles in energy storage, membrane structure, signaling, insulation, and vitamin absorption. Abnormal levels or metabolism of certain lipoproteins/lipid species can contribute to diseases such as cardiovascular disease.