Cholesterol is a waxy structure made by the liver of all mammals, including humans. It generally has a bad rap for contributing to heart disease, but in fact has many important functions in the body.
Cholesterol is Necessary for Human Life
Cholesterol is vital for body functions but is not considered an essential nutrient because it is not necessary to obtain from the diet. Humans make adequate amounts of cholesterol in their liver. "Without [cholesterol]," writes Dr. Johnathan Isaacsohn in The Yale University Heart Book, "mammalian life would not be possible."
Cell Membranes
One essential function of cholesterol is maintaining the integrity of cell membranes. It is present in the cell walls of organs, nerves and muscles.
Hormones
Cholesterol is needed to produce hormones, including adrenal hormones and the sex hormones estrogen and testosterone.
Vitamin D
Vitamin D is a steroid-like hormone which is made in the body from cholesterol. Dr. Denton D. Weiss, a board certified plastic surgeon, explains that a large amount of the vitamin is converted from a cholesterol compound into a form of the vitamin through the skin's exposure to sunlight.
Bile Acids
Cholesterol is a component of bile acids. Bile is produced in the liver and excreted through the gall bladder into the digestive tract when fat is eaten. Bile is needed to emulsify, or break up, fat molecules so they can be digested and absorbed. Without this process the body would not be able to absorb fat soluble vitamins and other nutrients.
