What is cholesterol?
Disease description:
My recent physical checkup indicated that my total cholesterol is high. I don't really understand what cholesterol means. Could you please explain what cholesterol is?
Doctor's answer (1)
Dr. Yang Ziqi
Cholesterol is a white or pale yellow crystalline substance and the primary steroidal compound in mammals. Its characteristics include:
1. Chemical properties: The chemical formula of cholesterol is C27H46O. It is insoluble in water but readily soluble in certain organic solvents such as ether and chloroform.
2. Physiological functions: Cholesterol serves multiple roles in the human body, including participating in bile acid formation to aid fat digestion, forming cell membranes to maintain cellular structural stability, and serving as a precursor for synthesizing hormones such as sex hormones and adrenal hormones.
3. Forms of existence: Cholesterol exists both inside and outside cells, particularly within cell membranes, where it accounts for more than 20% of membrane lipids. In the blood, cholesterol primarily exists in the form of cholesterol esters, with less than 10% present in the free form.
4. Sites of synthesis: The liver and intestinal mucosa are the main sites of cholesterol synthesis, with the liver producing 70–80% of the total cholesterol in the body.
