Cholesterol: A Definition And Function

High cholesterol is linked to heart disease. However, good cholesterol plays a vital role in the body.

Meat, eggs, and some dairy products are high in cholesterol.
Meat, eggs, and some dairy products are high in cholesterol.

Cholesterol is an organic substance that has a bad reputation, but this molecule actually plays an essential role in the human body since it helps to digest fats and synthesize hormones.

In this article, you'll find out more about cholesterol, including what it is and its function. Besides, we'll tell you about its discovery and the health implications of this debated nutrient.

What is cholesterol?

Cholesterol is a waxy substance found in animal tissue and a key component in the human body's composition. More specifically, this organic compound is not soluble in water, and its chemical formula is C27H46O. Also, it belongs to the biochemical lipid family.

This compound is made in the liver and then sent to all parts of the body through the bloodstream. When it accumulates in the blood, it can cause circulation problems.

Animals also have this substance in their bodies, which is why meat and other animal products tend to contain high levels of this. For example, foods like red meat, poultry, seafood, and dairy products all have cholesterol.

But, the body actually needs this organic molecule to digest fat from foods, to synthesize hormones, build cell walls and to participate in other crucial functions.

High cholesterol or LDL levels (low-density lipoproteins) is a contributing factor in heart disease. The plaques that are created by this substance accumulate in the heart's arteries. Over time, this restricts or blocks the blood supply, which causes atherosclerosis, which can eventually lead to a heart attack.

When was it discovered?

In 1770, cholesterol was discovered for the first time.  However, research on its structure didn't begin until the 20th century. This research was led by the chemist Adolf Windaus, who looked at its molecular composition. Windaus created a detailed structure for this compound -however, later, it was deemed inaccurate. Subsequently, in 1930, its true composition was uncovered.

Afterward, in 1951, the American chemist Robert B. Woodward completed these studies when he was able to synthesize it with simple compounds. Thanks to this achievement and his other work involving the creation of large molecules, Woodward was granted the Nobel Prize in chemistry in 1965.

Eggs and bacon is a high cholesterol breakfast favorite.
Eggs and bacon is a high cholesterol breakfast favorite.

Cholesterol function

As we said, cholesterol is a compound that is essential to the body. It is made in the liver and then used to produce bile, hormones, and nerve tissue.

More specifically, it belongs to a class of compounds known as steroids. Most steroids are natural compounds that play a critical role in physiology and the biochemical make up of both plants and animals.

However, as we mentioned, it's also part of the human diet. Organ meats are unusually high in cholesterol since 85 grams of beef liver contains an astounding 372 mg of cholesterol.

Because of cultural differences, the amount of cholesterol consumed varies depending on the local diet. For example, on average Europeans eat approximately 500 mg of this substance per day, while the Japanese consume about 130 mg per day -less than half since they tend to eat more fish.

Besides, the human body has a feedback mechanism that maintains serum levels of this substance. The liver itself produces approximately 600 mg every day, but this production rate changes depending on how frequently high LDL foods are eaten.

When a person eats more cholesterol, the liver cuts back its production of this compound. If intake goes well over the body's limits, this could cause arterial or heart disease.

Health implications

In 1910, the Russian biologist Nikolai Anitschkow discovered some of the first hints regarding the harmful effects that ingesting too much cholesterol could have on the body. This scientist gave rabbits food high in this organic molecule and found out that these animals became particularly susceptible to circulatory disorders, and post-mortem, they presented plaques on their artery walls.

Currently, eating a low cholesterol diet is the key to reducing the  risk  of heart disease.

On the same note, although further studies still need to be carried out, in 2001, a connection was found between cholesterol levels and Alzheimer's disease. Cutting back the LDL levels in the cells seems to block the senile plaques from connecting to the brain's neurons.


Newton, D. E. (2004). Cholesterol. In K. L. Lerner & B. W. Lerner (Eds.), The Gale Encyclopedia of Science (3rd ed., Vol. 2, pp. 864-865). Detroit: Gale.

Wells, K. R., & Odle, T. G. (2005). Cholesterol. In J. L. Longe (Ed.), The Gale Encyclopedia of Alternative Medicine (2nd ed., Vol. 1, pp. 468-472). Detroit: Gale.