Proteins of high biological value: what they are, characteristics and their sources.

A review of the characteristics of proteins of high biological value and where you can find them.

The term protein comes from the Greek word "proteios", which means fundamental or essential. The etymological origin of the word is not a simple coincidence, far from it, since proteins are indispensable elements for the human body. Proteins are indispensable elements for the correct development and functioning of the cells that make up our organism..

Proteins form a very broad and diverse family at a structural and functional level, in which we find some that act as hormones, such as insulin, which regulates Blood sugar levels; others that function as enzymes, such as lipases (essential in digestive processes) and even proteins with a defensive role in the organism, such as antibodies, which are so popular nowadays.

Today we are going to know a little more about the proteins known as proteins of high biological value.Those that contain some fundamental organic molecules for our organism, which must be incorporated through the diet, the essential amino acids.

What are proteins?

Proteins are large molecules, or macromolecules, formed by linear chains of amino acids.. They are generally composed of between 100 and 300 of these amino acids, although they can form longer chains. Depending on the amino acids that compose it and the order in which they are arranged, each protein will have a specific function in the organism.

All proteins are mainly made up of four elements: nitrogen (N), carbon (C), oxygen (O) and hydrogen (H); although they can contain sulfur (S) and phosphorus (P), and other elements in smaller proportions.

In addition to the functions described above, proteins act as an essential structural component in different types of tissues and can also be used as a source of energy for the organism, although they are not the most commonly used energy source.

Types of amino acids

Amino acids are organic molecules that combine to form proteins. So far, some 500 types of amino acids have been identified, about 500 different types of amino acids have been identified, but only 20 of them are going to form part of our proteins.all of which are necessary for the correct functioning of the human organism.

When we ingest food, our metabolism will be able to break down the proteins they contain into the amino acids that make them up, so that they can be used for the different bodily functions.

These amino acids can be classified into two groups depending on whether the human being has the capacity to synthesize them by himself or not: essential amino acids and non-essential amino acids.

1. Essential amino acids

Essential amino acids are those that cannot be produced by man, and, therefore, we have to incorporate them through the diet.. When any of these amino acids is absent in the organism or is below the necessary levels, the correct functioning of the different tissues that make up the human body can be put at risk.

Within this group we find 8 amino acids: valine, leucine, isoleucine, phenylalanine, tryptophan, threonine, methionine and lysine. In the case of newborns, one more amino acid has to be added to this list, histidine, as their body is not sufficiently developed to be able to produce it autonomously.

2. Non-essential amino acids

On the other hand, non-essential amino acids are those that can be produced by our body from other protein components, and therefore, it is not necessary to produce them autonomously.Therefore, they do not need to be consumed through the diet. This group of amino acids includes: alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine (in adult individuals), proline, serine and tyrosine.

What are high biological value proteins?

Having defined the difference between essential amino acids and non-essential amino acids, we can delve a little deeper into the concept of high biological value protein. According to the European Food Information Council (EUFIC), when we say that a protein has a high biological value, we mean that it contains the essential amino acids in a proportion equal or similar to that required by humans..

On the other hand, in those cases in which one or more of these essential amino acids is not present, or the levels in which it is present are not sufficient, we speak of proteins of low biological value. The essential amino acid that presents the lowest values in comparison to the required levels receives the name of limiting amino acid..

Calculation of the biological value

The biological value (BV), as indicated in the previous section, refers to the quality of a protein. To calculate it, the nitrogen used in the formation of the tissues that compose the organism must be divided by the nitrogen that is absorbed through the food we ingest..

The final result of the biological value is expressed as a percentage of nitrogen used and gives us an idea of the efficiency with which our body uses the proteins ingested through the diet.

The biological value takes on values between 0 and 100The biological value takes on values between 0 and 100, so that a BV of 100% indicates that all the protein that has been ingested is utilized and incorporated into our body's proteins. Conversely, negative values can also occur, when more protein is eliminated than is ingested.

We can conclude then that a protein source of high biological value correlates with an adequate supply of essential amino acids, which will be used by our body in different functions.

Dietary sources of proteins of high biological value.

We can find proteins in different types of foods, both of animal and vegetable origin. The differences between the protein contribution that can be made by one food or another will be marked mainly by the amounts of protein in each type of food, rather than by the types of proteins.more than by the types of proteins present. Beyond the final quantity that a food provides us, we must look at the quality of these proteins, which depends on the amino acids that form it.

Generally speaking, protein sources of animal origin have a higher biological value. than those proteins that come from vegetable sources. However, each food of vegetable origin usually has a different limiting amino acid, that is to say, an amino acid that is found in a lower proportion than the rest with respect to the required values.

This fact will allow us to make up for these deficiencies in vegetable protein sources by combining several foods in the same meal. In this way, making the simultaneous intake of two vegetable sources, for example, legumes and cereals, the amino acids of one protein will compensate for the limitations present in the other type of protein and vice versa, allowing us to achieve a combination of protein sources in the same meal.This allows us to achieve a combination of a much higher biological value.

People who follow an omnivorous diet do not usually have problems in obtaining the right amount and type of proteins according to their nutritional requirements. It is in the case of diets that avoid or eliminate foods of animal origin in which appropriate monitoring should be carried out, since they may present some difficulties in supplying the body with the necessary levels of protein for its proper functioning.

Sources of animal origin

Among the foods with proteins of animal origin the following stand out.

1. Egg

The proteins present in the egg are of an excellent quality and are considered to have the highest biological value.. The white is the portion of the egg with the highest protein concentration.

2. Dairy products

They are a source of proteins of great quality, which in addition another fundamental element for our development, calcium.. Their biological value is also very good, especially that of milk proteins.

3. Meats

They provide us with a good amount of quality proteins, although they also provide saturated fats, especially red meats. also provide saturated fats, especially red meats.. We must take into account the type of meat that we consume, as well as the type of piece, since we can reduce in this way the amount of ingested fat.

4. Fish

In addition to proteins of very good quality, they will provide us with polyunsaturated fats of the omega 3 type, being especially abundant in the fish.being especially abundant in oily fish (sardines, salmon, tuna or anchovies).

Sources of vegetable origin

These are some examples of quality protein sources of vegetable origin.

1. Nuts and dried fruits

They contain a large amount of protein and also provide healthy fats.. Their consumption should be moderate, given their high caloric content.

2. Legumes

They are another very good source of proteins and a very complete food. The quality of these proteins improves when ingested in combination with cereals, such as rice, as they contain amino acids that complement each other.as they contain amino acids that complement each other. For example, soy is one of the legumes with the highest and best quality protein content.

3. Cereals and pseudocereals

Cereals provide proteins, which complement very well with those provided by legumes. Quinoa, a pseudocereal very extended nowadays, stands out.It contains all the essential amino acids.