Cholesterol Function: Definition, Types and Levels of This Essential Substance for the Body

Many people think that cholesterol only plays a negative role in the body, damaging health, but that is not true.

It is necessary to understand that cholesterol is a type of fat in the human body, specifically lipid. It can be good or bad for human health, depending on the levels of fat found in the body.


There are two types of cholesterol with different functions, one positive and one harmful for health. The first is HDL cholesterol, which removes excess fat from the arteries by reducing the formation of fatty plaques in the body and improving health.

The second cholesterol, called LDL, is considered harmful and dangerous for health, as it promotes clogging of the arteries. You must know the functions of cholesterol.

Cholesterol levels

Cholesterol levels must always be balanced. Therefore, it is essential to maintain a balanced diet with little fat. It is important to remember that, at normal levels, the functions of cholesterol are positive for health and have many essential functions for the body.

The body uses the functions of cholesterol to restructure damaged cells and maintain physical health. This fat is present even in breast milk, playing a fundamental role in the nutrition and health of babies, who need rich foods and which promote the development of the entire nervous system.

The functions of cholesterol can also help prevent many health problems.


Cholesterol is necessary to build and maintain membranes; it modulates membrane fluidity in the physiological temperature range.

The hydroxyl group in cholesterol interacts with the polar groups of membrane phospholipids and sphingolipids. At the same time, the steroid and hydrocarbon chain is incorporated into the membrane, along with the nonpolar fatty acid chain of the other lipids.

Through interaction with phospholipid fatty acid chains, cholesterol increases the membrane of the container, reducing the membrane’s fluidity. In this structural role, cholesterol reduces the permeability of the plasma membrane to neutral solutes, protons (positive hydrogen ions), and sodium ions.

Cholesterol also functions in intracellular transport, nerve conduction, and cell signaling within the cell membrane. Cholesterol is essential for the structure and function of invaginate caveolae and clathrin-coated pits, including caveolae-dependent and clathrin-dependent endocytosis.

The role of cholesterol in such endocytosis can be investigated using methyl beta cyclodextrin (MβCD) to remove cholesterol from the plasma membrane.

Recently, cholesterol has also been implicated in cell and signaling processes, assisting in forming lipid rafts in the plasma membrane.

Lipid raft formation brings receptor proteins into proximity with high concentrations of molecules. In many neurons, a myelin sheath, rich in cholesterol and derived from tight layers of Schwann cell membrane, provides insulation for more efficient conduction of impulses.

Inside cells, cholesterol is the precursor molecule in several biochemical pathways. In the liver, cholesterol is converted into bile, stored in the gallbladder.

Bile contains bile salts, which solubilize fats in the digestive tract and help intestinal absorption of fat molecules, as well as the fat-soluble vitamins A, D, E, and K.

Cholesterol is an important molecule and precursor for the synthesis of vitamin D and steroid hormones, including the adrenal gland of cortisol and aldosterone and the sex hormones progesterone, estrogens, and testosterone, their derivatives. Some research indicates cholesterol may act as an antioxidant.

In addition to all the above, it must be remembered that cholesterol can be treated by drugs such as Lipitor.

In summary, nine main functions of cholesterol in our body are presented below.

  1. Your body uses cholesterol to make the hormone that helps fight stress and protect you against heart disease and cancer.
  2. Your body needs cholesterol to make all the sex hormones, including androgens, testosterone, estrogen, and progesterone.
  3. Your body uses cholesterol to make vitamin D, vital for your bones and nervous system, growth, mineral metabolism, muscle tone, insulin production, reproduction, and immune system function.
  4. Bile salts are made from cholesterol. Bile is vital for digestion and assimilation of dietary fat.
  5. Cholesterol acts as an antioxidant, protecting us against free radical damage that leads to heart disease and cancer.
  6. Cholesterol is required for the proper function of serotonin receptors in the brain. Since serotonin is a chemical that promotes wellness, it is not surprising that low cholesterol is correlated with aggressive and violent behavior, depression, and suicidality.
  7. Breast milk is especially rich in cholesterol and contains a particular enzyme that helps the baby use this nutrient. Babies and children need cholesterol-rich foods for their growth, ensuring brain and nervous system development.
  8. Cholesterol from your diet plays a vital role in maintaining a healthy gut. That is why a vegetarian diet with low cholesterol can lead to porous bowel syndrome and other intestinal problems.
  9. The body uses cholesterol to repair damaged cells. This means that high cholesterol levels are beneficial. What is said about fat and cholesterol to harden the arteries is like accusing the white blood cells of the cause of infection instead of helping the immune system repair the problem.