What exactly are proteins?

Proteins are large organic molecules made up of long chains of amino acids that are linked by bonds known as peptide bonds.

Human proteins are made up of 20 amino acids. There are 8 of them (essential amino acids) that are not synthesized in our body and it is necessary to acquire them through diet intake and the other 12 (non-essential amino acids) can be manufactured by our body.

When dietary recommendations talk about providing the necessary proteins to our body, they are really talking about essential amino acids.

Proteins are present in all cells of the body and they are responsible for around half weight of the whole tissues of our body. In addition, they participate in practically all biological processes that occur.

How do proteins work?

Each species, whether animal or plant, is made up of its own type of proteins and they are totally incompatible with those of other species.

That is why our body is unable to directly assimilate proteins from food. In order to absorb, assimilate and use them, it is essential that during digestion, by means of enzymes and gastric juices, they are previously broken down into amino acids.

Once this process is completed, the amino acids enter in to the blood and are distributed throughout the tissues, combining with other amino acids from other proteins that have been degraded.

What is the function of proteins?

Proteins are essential for our body, since without them our muscles would not exist. But they are not only necessary for this, they perform many important tasks which are also very important. It could be said that they are used for almost everything since they are present in most of the vital functions of the body.

In addition to help to build muscles, they also provide the materials which make bones, internal organs, glands, hair, skin, and nails.

Proteins help to slow the aging of the body and act as an energy source when carbohydrates and fats are scarce. Likewise, the transmission of nerve impulses, muscle contraction and immune protection depend on them.

Where are proteins found?

Proteins are found in all tissues and practically in all foods as they are a constituent element of all cells.

What does vary, depending on its origin, is its concentration and its nature. Due to this, two major sources of protein can be established: proteins of animal origin (meat, fish, eggs and dairy) and proteins of plant origin (legumes, cereals and nuts).

Are all proteins the same?

Obviously not. There are proteins of different qualities depending on the amount of essential amino acids they contain and in what proportion.

Due to the simple fact that a single amino acid is missing, the protein significantly loses quality since, for our body to be able to form its proteins, it is necessary that it have all the essential components. Similarly, the amount of amino acids does not compensate for each other. That is, the increase of one amino acid does not compensate for the absence of another. For this reason, proteins animal origin are considered of better quality than proteins of plant origin.

In addition to the quality of the proteins, we must take into account the amount that our body can take advantage and assimilate once digested. For example, within vegetable proteins, soybeans have a higher net protein contribution than others because our digestive system assimilates their proteins better even though their biological value is lower.

Definitely, and due to its biological value and its complete composition, proteins of animal origin are the most valued and recommended to obtain a complete supply of all the nutrients that our body needs. Another good option is to combine these proteins of animal origin with others of plant origin in our diet intake.

How much protein do we need?

Here it is important to distinguish between various factors but, above all, if we lead a sedentary life, where the needs will always be lower and if we lead an active life and practice some kind of sport.

We are going to focus on the second option because it is recommended and practically necessary to practice some sport activity and lead a healthy lifestyle.

A healthy adult who practices an aerobic endurance sport should consume between 1.2-1.4 grams of protein per day for every kilo of weight, increasing slightly for those who practice marathon or long-duration and high-intensity sports due to its high energy expenditure.

For a healthy adult, who practices strength sports with the aim of increasing and enhancing his muscle mass, can take between 1.6-2 grams of protein per day for every kilo of body weight.

Problems derived from a lack of proteins:
  • If we do not provide the necessary daily amount that our body needs, it will look for them in its own tissues, causing a loss of muscle mass.
  • We will have an immune system which is more vulnerable to infection.
  • We will find ourselves more both tired and physically and mentally.
  • Metabolic processes slow down.
  • The ability to eliminate waste products, such as free radicals, which causes aging in our body, is reduced.