Types of fats (good and bad) and their functions

Fats, lipids and their functions in our organism. How are they classified?

Lipids are organic biomolecules generally made up of carbon and hydrogen and, to a lesser extent, oxygen. and, to a lesser extent, oxygen. However, they can sometimes also contain phosphorus, nitrogen and sulfur.

The world of lipids can be a confusing terrain, as the terms lipids, fats, fatty acids or triglycerides can be used interchangeably even though they do not mean the same thing. In this article we will focus on fats and their nutritional significance, so we will not go into detail about other important functions of lipids, such as their structural or transport function.

Simple lipids and complex lipids

The lipid group includes many organic compounds that basically share two essential characteristics: they are insoluble in water and soluble in organic solvents. Traditionally, a distinction is made between simple lipids and lipids that are soluble in water and organic solvents.n the traditional way, a distinction is made between simple lipids (fatty acid esters with alchols) and complex lipids..

The most important simple lipids are triglycerides, which are usually called fats because they are stored in adipose tissue and are the main constituents of vegetable oils and animal fats, and their function is basically energetic, but also insulating. Triglycerides are largely composed of fatty acids, e.g., malic acid. Complex lipids, on the other hand, often have structural and functional tasks.

The fact that the properties of all these substances are different means that their metabolism is also significantly different.

Functions of lipids

In general, the functions of lipids are:

• EnergeticFor each gram, lipids provide 9 Kcal. If the intake of fats exceeds the daily needs, they are stored directly in the adipose tissue in the form of triglycerides.
• StructuralStructural: Some lipids such as cholesterol are part of cell membranes and are precursors of steroid hormones, bile acids and vitamin D.
• TransportTransport of fat-soluble vitamins (A, D, E, K and carotenoids).
• Increase palatabilityThey enrich the taste of food.

In addition, lipids provide essential fatty acids for the organism.

Essential and non-essential fatty acids

Fatty acids, like amino acids, can be divided into essential and non-essential fatty acids. The difference between them is that the essential ones must be ingested from the diet and the non-essential ones can be produced by the organism. Although the essential ones are classified in families such as Omega 3 fatty acids, the best known are, for example, linoleic acid or alpha-linolenic acid.

• You can learn more about essential amino acids in our post: "The 20 types of proteins and their functions in the body".

Saturated, unsaturated or trans fats (or fatty acids).

Fatty acids, according to their chemical structure, can also be classified in different ways:

Saturated fats

All fat-containing foods are composed of different types of fat, but the amounts of each type usually differ depending on the food. For example, pork is rich in saturated fat, while almonds are rich in unsaturated fats (also known as healthy fats).

The fatty acids in these fats do not have double bonds in their chain and are generally solid at room temperature.. The body cannot take full advantage of this type of fat, so in the long run it accumulates in the arteries, which can cause serious health problems. That is why different organizations specialized in this subject warn that the consumption of this type of fat should be moderate.

Saturated fat increases cholesterol more than any other type of fat (except trans fat, which we will discuss later), so excessive consumption can increase cholesterol biosynthesis and has a thrombogenic effect. It is found in foods of animal origin such as meats, sausages, milk and its derivatives (cheese, ice cream).

Unsaturated fats

Unsaturated fats are known as healthy fats because they increase good cholesterol.They stabilize the Heart rhythm, relieve inflammation and, in addition, provide other beneficial functions for our organism. This type of fat is found predominantly in plant foods and fish.

Two types can be distinguished:

• Monounsaturated fats.Monounsaturated fats: This type of fat is found, for example, in olive oil, and the best known monounsaturated fatty acid is oleic acid. They are usually liquid at room temperature and have only one double bond in their structure.
• PolyunsaturatedThey are found in foods of vegetable origin, fish and seafood. They have two or more double bonds in their structure and are essential. They are classified in groups such as Omega-6 (linoleic and arachidonic acid) or Omega-3 (linolenic, eicosapentaenoic or docosahexaenoic acid).

Trans fats

If saturated fats are harmful to the body in the long term, trans fats (transformed fats) found in hydrogenated oils and certain processed foods are even worse. Technological processes, such as hydrogenation, oil refining, etc., cause a chemical transformation, cause a chemical transformation in certain fatty acids, which turns them into a harmful substance for our body.

Health professionals have long warned that diets high in trans fats increase beta-amyloid in the brain, which is associated with Alzheimer's disease. In addition, the journal Neurology published research that found that this type of fat is associated with brain shrinkage and an increased risk of stroke.

Other classifications of fat:

In addition to the above, fat can be classified differently:

According to its origin.

Fat can also be classified depending on the source from which it is obtained and can be of vegetable or animal origin. Examples of animal fat is the one that we can find in the eggs or the veal meat; whereas those of vegetable origin are, for example, the one that is found in the dry fruits or the olives.

According to their form

According to their form they can be solid or liquid. The liquid ones are known as oils and the solid ones as fats, simply. This difference can be appreciated with the naked eye, although it is certain that the consistency of the fats can vary and have a gelatinous texture that resembles that of the liquids.

This classification of the fats can be made at a glance.

According to their visibility

Finally, fat can be classified as visible or invisible. The visible fat is, for example, that one that is in a piece of loin, reason why it is possible to retire it and not to consume it. On the other hand, invisible fat is, for example, the one found in milk.