The term protein comes from the Greek word “protein”, which means fundamental or essential. The etymological origin of the word is not a mere coincidence nor by any means, since proteins are essential elements for the proper development and functioning of the cells that make up our body.
Proteins form a very large and structurally and functionally diverse family, in which we find some that act as hormones, such as insulin, which regulates blood sugar; others that work like enzymes, like lipases (essential for digestive processes) and even proteins with a defensive role in the body, like antibodies, so in everyone’s mouth today.
Today we will learn a little more about what are called proteins of high biological value, those which contain certain organic molecules essential to our organism, which must be incorporated through food, essential amino acids.
What are proteins?
Proteins are large molecules, or macromolecules, formed by linear chains of amino acids.. They are usually made up of 100 to 300 of these amino acids, although they can form larger 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 body.
All proteins are made up mainly 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 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 source of energy. most commonly used.
Types of amino acids
Amino acids are organic molecules that combine to form proteins. Bye now, around 500 different types of amino acids have been identified, but only 20 will be part of our proteins, all of which are necessary for the proper functioning of the human body.
When we eat food, our metabolism will be able to break down the proteins in it into the amino acids that compose it, so that these 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 on their own or not: essential amino acids and non-essential amino acids.
1. Essential amino acids
Essential amino acids are those that cannot be produced by humans and therefore we must incorporate them into the diet. When any of these amino acids are missing from the body or are below the required levels, the proper functioning of the various tissues that make up the human body can be compromised.
Within this group we find 8 amino acids: valine, leucine, isoleucine, phenylalanine, tryptophan, threonine, methionine and lysine. In the case of babies, another amino acid, histidine, must be added to this list, because their organism is not sufficiently developed to be able to produce it independently.
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 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 adults), proline , serine and tyrosine.
What are the proteins of high biological value?
Once we have defined the difference between essential amino acids and non-essential amino acids, we can dig 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 essential amino acids in a proportion equal or similar to that required by humans.
On the other hand, in cases where one or more of these essential amino acids are not present, or the levels in which it is found are not sufficient, one speaks of proteins of low biological value. The essential amino acid that has the lowest values relative to the required levels is called the limiting amino acid..
Calculation of biological value
Biological value (BV), as discussed in the previous section, refers to the quality of a protein. To calculate, it is necessary to divide the nitrogen used in the formation of the tissues that make up the body, among the nitrogen which is absorbed by the food we eat..
The final result of the biological value is expressed as the percentage of nitrogen used and gives us an idea of how efficiently the body uses the proteins ingested from the diet.
The biological value acquires values between 0 and 100, so a 100% BV tells us that all the proteins that have been ingested are used and incorporated into the proteins in our body. Conversely, negative values can also be given, when more protein is removed than ingested.
We can then conclude that a source of protein of high biological value is correlated with an adequate supply of essential amino acids, which will be used by our body for different functions.
Food sources of protein with high biological value
We can find protein in different types of food, both animal and plant origin. The differences between the protein intake that one food or another can provide us will be marked mainly by the amounts of protein in each type of food., rather than the types of protein 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 compose it.
In general, animal protein sources have a higher biological value as those proteins that come from plant sources. However, each food of plant origin generally has a different limiting amino acid, that is, an amino acid which is in a lower proportion than the rest compared to the required values.
This fact will allow us to fill these deficiencies in vegetable protein sources by combining several foods in the same food. In this way, making the simultaneous intake of two vegetable sources, for example, legumes and cereals, amino acids in one protein will compensate for limitations present in the other type of protein and vice versa, making it possible to obtain a combination of much greater biological value.
People who follow an omnivorous type diet generally have no problem getting the right amount and type of protein based on nutritional needs. It is in the case of diets that avoid or eliminate foods of animal origin that a proper control must be carried out, as they may present certain difficulties in providing the body with the levels of protein necessary for its proper functioning.
Sources of animal origin
Among the foods containing animal protein, the following stand out.
The proteins present in the egg are of excellent quality and are considered to have a higher biological value. Egg white is the part of the egg that has a higher concentration of protein.
2. Dairy products
They are a source of high quality protein, which in addition they provide another key element for our development, calcium. Its biological value is also very good, especially that of milk proteins.
They provide us with a fair amount of quality protein, although they also provide saturated fat, especially red meats. We have to take into account the type of meat we eat, as well as the type of piece, because in this way we can reduce the amount of fat ingested.
In addition to very good quality proteins, they will provide us with omega 3 polyunsaturated fats, being particularly abundant in blue fish (sardines, salmon, tuna or anchovies).
Sources of plant origin
Here are some examples of quality sources of plant protein.
They contain a high amount of protein and also provide healthy fats. Its consumption should be moderate, given its high caloric content.
They are another very good source of protein and a very complete food. The quality of these proteins improves when ingested in combination with cereals, such as rice.because it contains complementary amino acids. For example, soy is one of the highest protein and best quality legumes.
3. Cereals and pseudo-cereals
Cereals provide proteins, which complement each other very well with that provided by legumes. Highlights include quinoa, a pseudo-grain that is widely used today, which contains all the essential amino acids.
- Healthy Lifestyles – Protein (sf). Ministry of Health. Retrieved from https://estilosdevidasaludable.sanidad.gob.es/alimentacionSaludable/
- High and low biological value protein foods. (2008). Eufique. Retrieved from https://www.eufic.org/en/whats-in-food/article/the-basics-proteins
- Hoffman, JR and Falvo, MJ (2004). Protein – Which is better ?. Journal of Sports Science and Medicine, 3 (3), 118-130.