CHOLESTEROL

a substance in animal tissue that is an essential component of cell membranes and nerve fiber insulation. Cholesterol is important for the metabolism and transport of fatty acids and in the production of hormones and Vitamin D. Cholesterol is manufactured by the liver, and is also present in certain foods (e.g., eggs, shellfish). There are 2 types of cholesterol in the blood, high-density (HDL) and low-density (LDL) lipoproteins. Very low cholesterol levels may indicate malnutrition.