Lipids: what are they, types and functions

Lipids play important roles in the body. They not only serve as an energy reserve, but also intervene in the transport of some nutrients. How are they classified?

Lipids play a very important role in health. Not only are they key as an energy reserve for the body, but they also intervene in essential processes of the body such as, for example, the transport of nutrients, the regulation of body temperature, among others.

Together, these substances are diverse and come from various sources. In fact, they are known for the role they play in feeding living beings, since they are key for the assimilation of some vitamins and for an optimal functioning of the metabolism.

What exactly are lipids? Its duties? Since we usually read or hear this term when it comes to health and nutrition, it is convenient that we solve these questions. We will detail more about it below.

What are lipids?

Lipids are a group of biological molecules that intervene in relevant processes in the body. In particular, they are part of the cell membrane, are the basis for the production of hormones and, above all, are responsible for storing energy. 

They are composed of hydrogen and carbon, although to a lesser extent they can contain sulfur, nitrogen or phosphorus. In any case, they are characterized by being insoluble in water and by representing one of the main energy reserves for the body.

Now, although the term lipid is often used to refer to fat, it is important to note that not all lipids are fats , but all fats are lipids. Thus, we find several types of lipids, which are classified according to their physical properties and the functions they perform.

Types of lipids

As detailed in an article published in the scientific research, the term lipids groups together various compounds that have relevant biological functions. Therefore, when talking about these substances, it is important to know how they are classified. What types of lipids are there?


Phospholipids are made up of chains of fatty acids, phosphate, and glycerol. They form hydrophobic structures, which means that they repel water. Its most important function is the formation of cell membranes.

In addition, they also carry out other actions, such as the digestion of other fats in the small intestine. The body is capable of generating all the phospholipids it needs.


Cholesterol is an essential molecule for the body. Contrary to what many people think, it is not always bad. It is part of cell membranes; In addition, it is the precursor of different substances, such as some vitamins or hormones such as steroids.

Therefore, a certain amount of cholesterol is essential for the body to function properly. However, too much of it can cause it to accumulate in the blood vessels. This is a problem, since these vessels can become clogged and, consequently, there is a greater risk of heart attacks or ischemic problems.


Glycolipids are fats that also contain sugar molecules in their structure. Its most important function is related to the immune system. They are found on the outside of the cell membrane and function as a signal for it.


The triglycerides are composed of fat and alcohol. Specifically, they are the molecules into which excess energy or sugars in the body are transformed. That is, they will form its energy reserves.

As with cholesterol, an excess of triglycerides also tends to accumulate in the blood vessels and in the rest of the body. Because of this, its high levels are associated with health problems.


The steroids are molecules formed by cholesterol and hormones. Some examples may be testosterone or estrogens. These need cholesterol to be synthesized in the body. Specifically, they perform regulatory and activating functions.

What are its functions in the body?

Lipids, depending on their type, carry out different essential functions in the body. According to a publication in Molecular Biology of the Cell, these are structural or signaling functions. In the following space we detail some of the most important ones.

Energy reserve

The main function of this substance is to serve the body as an energy reserve. One gram of fat can provide 9 kilocalories to the body. When a person has an excess of sugars, these are stored in the form of fat deposits. They will be used when other sources of energy, such as carbohydrates, are lacking.

Structure formation

Some lipids form important structures in the body. The most important example is about cell membranes. They are made up of a specific type of lipid; in turn, they are essential to shape and protect the cell. 

Cellular communication

Cells communicate with each other through different substances that function as signals, such as vitamins, hormones, and glycolipids. These have the function of regulating some secretions and various responses of the body.


There are lipids that function as transporters for other substances through the body, such as nutrients. In general, this function is performed in conjunction with bile acids and lipoproteins. 

Thermal regulation

The fat deposits that accumulate under the skin and around the organs act as protectors from the cold. Fat prevents heat from dissipating out, which prevents the body from cooling down.

What to remember about lipids?

Although the types and functions of lipids are varied and complex, in general they are organic compounds essential for life. To a certain extent, they are decisive for the proper functioning of the body. However, in excess, some varieties are harmful.

Therefore, it is convenient to maintain healthy lifestyle habits, especially in relation to food, and to carry out regular medical check-ups. In case of any abnormality in its levels, it is essential to follow medical treatment.

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