I.

Introduction

Cholesterol, a waxy, fatlike compound that is found throughout the body. Cholesterol is notorious for its role in clogging arteries and thus contributing to heart disease and stroke. But cholesterol is essential to the body, too. It is an important component in cell membranes, and the body uses cholesterol in making sex hormones, adrenal hormones, and vitamin D. Chemically, cholesterol is a complex alcohol of a type known as sterols. It is also a lipid, which means that it does not dissolve in water.