Proteins Of High Biological Value: What They Are, Characteristics And Their Sources
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 essential elements for the correct development and functioning of the cells that make up our body
Proteins form a very large 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 body, such as antibodies, so much on everyone’s lips today.
Today Let’s learn a little more about what are known as proteins of high biological value those that contain fundamental organic molecules for our body, which must be incorporated through the diet, the essential amino acids.
Proteins are large molecules, or macromolecules, made up of linear chains of amino acids Generally, they are composed of between 100 and 300 of these amino acids, although they can form longer chains. Depending on the amino acids that make it up and the order in which they are arranged, each protein will have a specific function in the body.
All proteins are mainly made up of four elements: nitrogen (N), carbon (C), oxygen (O) and hydrogen (H); although they may contain sulfur (S) and phosphorus (P), and other elements in smaller proportions.
In addition to the functions that we have 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 body, although they are not the most commonly used energy source.
Types of amino acids
Amino acids are organic molecules that combine to give rise to proteins. Until now, About 500 different types of amino acids have been identified, but only 20 of them will be part of our proteins all of them being necessary for the correct functioning of the human organism.
When we eat 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 different bodily functions.
These amino acids can be classified into two groups depending on whether humans have the ability to synthesize them themselves or not: essential amino acids and non-essential amino acids.
1. Essential amino acids
essential amino acids They 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 body 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, another amino acid must be added to this list, histidine, since their body is not developed enough to be able to produce it autonomously.
2. Non-essential amino acids
For its part, Non-essential amino acids are those that can be produced by our body from other protein components , and therefore, it is not necessary that they be consumed through the diet. This group of amino acids includes: alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine (in adults), proline, serine and tyrosine.
What are proteins of high biological value?
Once the difference between essential amino acids and non-essential amino acids has been defined, we can delve a little deeper into the concept of protein of high biological value. According to the European Food Information Council (EUFIC), when we say that a protein has a high biological value, we mean that contains essential amino acids in a proportion equal to or similar to that required by human beings
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 found are not sufficient, we speak of proteins of low biological value. The essential amino acid that has the lowest values compared to the required levels is called the limiting amino acid
Calculation of biological value
The biological value (VB), as we have 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 make up the body must be divided by the nitrogen that is absorbed through the food we eat
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 100 , so that a BV of 100% indicates that all the protein that has been ingested is used and incorporated into the proteins of our body. On the contrary, 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 animal and plant origin. The differences between the protein contribution that one food or another can give us will be marked mainly by the amounts of protein in each type of food , more than by the types of proteins present. Beyond the final quantity that a food provides us, we must look at the quality of those proteins, which depends on the amino acids that make them up.
In general terms, protein sources of animal origin have a higher biological value than those proteins that come from plant sources. However, each food of plant origin usually has a different limiting amino acid, that is, 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 protein sources of plant origin by combining several foods in the same meal. In this way, by simultaneously ingesting two plant 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 much greater biological value.
People who follow an omnivorous diet do not usually have problems obtaining the appropriate amount and type of protein according to their nutritional requirements. It is in the case of diets that avoid or eliminate foods of animal origin that adequate monitoring must be carried out, as they may present some difficulties in supplying the body with the necessary levels of protein for its proper functioning.
Among the foods with proteins of animal origin, the following stand out.
1 egg
The proteins present in the egg are of excellent quality and are considered to have the highest biological value The white is the portion of the egg that has the highest concentration of protein.
2. Dairy
They are a source of high quality proteins, which also They provide another fundamental element for our development, calcium Its 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 We must take into account the type of meat we consume, as well as the type of piece, since in this way we can reduce the amount of fat ingested.
4. Fish
In addition to very good quality proteins, They are going to provide us with polyunsaturated fats of the omega 3 type being especially abundant in blue fish (sardines, salmon, tuna or anchovies).
You may be interested: “Types of fats (good and bad) and their functions”
Plant-based sources
Here are some examples of quality plant-based protein sources.
1. Nuts
They contain a large amount of protein and also provide healthy fats Its consumption should be moderate, given its high calorie content.
2. Legumes
They are another very good source of protein and a very complete food. The quality of these proteins improves when they are ingested in combination with cereals, such as rice , since it contains amino acids that complement each other. For example, soybeans are one of the legumes with the highest protein content and the best quality.
3. Cereals and pseudocereals
Cereals provide proteins, which complement very well with those provided by legumes. Quinoa stands out, a pseudocereal that is widespread today which contains all the essential amino acids.
