Proteins: what they are and where they are found

What are proteins and where are they found? We are the first to mention them many times, but who among us would be able to define them or explain what types of proteins exist? It is certainly not obvious, as it is not to list foods and foods that contain them. Keep calm, then, and read on!

We will try to clarify precisely these points: what proteins are, how they work, why they are so important for our body and in which foods to find them. But to start with, here are 5 super-protein foods you should never miss:

Proteins: what they are and what they are

Let's start with the name: the term "protein" comes from the Greek "proteios" which means "in the first place". This should already be enough to make us clear the importance of this constituent element and how fundamental it is for the human body!

Proteins are molecules with a well-defined structure, discovered in 1953 by the scientist Frederick Sanger, who was studying insulin. This fixed structure is made up of amino acids, whose sequence depends on the type of protein and its function.

Each amino acid is composed of a carbon atom to which a carboxylic group, an amino group, a hydrogen atom and a side chain (called R group) are bonded, and it is the latter that differentiates one protein from the other. Each protein has a specific role and carries genetic information within it.

There are, in all, 20 types of amino acids, of which 8 are called "indispensable" or "essential" because the human body cannot manufacture them by itself.

We can distinguish proteins in different ways: in monomeric or polymeric depending on whether they are made up of one or more polypeptide chains (ie in which the amino acids are repeated at least once each); in simple and conjugated, if they are composed only of amino acids or also of other chemical elements.

We also remember that proteins are subject to continuous replacement, the so-called "protein turnover", which allows to eliminate the degraded ones and replace them with new proteins.

See also

Protein foods: the 15 foods richest in protein

How much protein per day? How many do our pro needs really require

Dissociated diet: separate proteins and carbohydrates at lunch and dinner to lose weight

What are they for? The function of proteins and our needs

After better understanding what proteins are and what their structure is, let's try to understand what they are for. Proteins are essential for the proper functioning of the organism and play numerous roles and properties.

First of all, they can be considered the "building blocks" of the body: they participate in the development and maintenance of organs and muscles (they are found in the cells of the latter and allow them to contract).

They then govern the functioning of the organism: from the hormonal system (in which they perform a regulatory function) to the transmission of information and substances in the blood vessels, from the immune system (they are essential for counteracting the risk of infections and diseases) to maintaining internal temperature Enzymes have the function of accelerating biological reactions, acting as catalysts.

They also contribute to weight loss (have you ever heard of a protein diet?), Reducing appetite and ensuring the maintenance of lean mass (muscles) at the expense of fat mass.

Every day we renew about 2.5% of our protein reserve (from 250 to 300 g per day on the 11 kg of protein that the body of an adult contains). That is why, since the body does not stock up on proteins, the daily diet must provide at least an amount of protein equivalent to what we burn. Otherwise there is a risk of alterations to the muscles and organs. Therefore, it is recommended to take 1 g of protein for every kg of body weight, that is, for a person weighing 50 kilos, 50 g of protein.

Protein in food: where is it found? In which foods?

Proteins are present in many foods, both in foods of plant origin and of animal origin. Animal proteins are those contained in meat, fish, but also in their derivatives, such as eggs, cheeses and dairy products.

A few examples: 100 g of chicken breast = 22 g of protein; 100 g of minced meat = 26 g; 100 g of hake = 19 g; 100 g of eggs = 13 g; 100 g of gruyere = 29 g.

Vegetable proteins, on the other hand, are found mainly in cereals, some vegetables and legumes (lentils, peas, broad beans ...). Some examples: 100 g of cooked lentils = 8 g of protein; 100 g of whole wheat petals = 11 g.

Find out about the protein diet in the book The 7 Day Dukan Diet on offer on Amazon at € 9.26
Browse our album now to find out which are the most protein-rich vegetables:

See also: Vegetable protein: the list of all the most high-protein vegetables

© iStock Vegetable proteins

Animal and vegetable proteins: the differences

Proteins determine the nutritional value of a food, but also its physical characteristics. It will be based on the presence of essential amino acids and their digestibility that a food can be considered a carrier of proteins with high biological value (BV) or not.

The biological value required of a food is equal to or greater than 100, otherwise it means that it does not have a correct protein intake. Vegetable proteins are to be considered incomplete compared to animal proteins, because they lack some essential amino acids. So pay attention to your diet: you will have to find a way to satisfy the daily protein requirement for a correct functioning of the organism.

Every self-respecting diet should focus on increasing the consumption of high VB proteins, in parallel with the decrease in the intake of fats and carbohydrates: in this way you will be able to maintain lean mass while maintaining metabolism active (the process of protein turnover burns a lot of calories!) and affecting only the fat mass.

To find out more, see the book Green proteins. The bible. by Fern Green available on Amazon for € 12.66

Check out the plant-based protein options available on Amazon

Supplements: are protein powders bad for you?

Taking the right daily amount of protein is essential for our health and, in specific and particular cases, it may be necessary to take supplements to meet this requirement.

However, protein powders should always be taken under medical supervision and it is important that your doctor recommended them. Consuming them without specific expertise could decrease their effectiveness or cause a series of side effects ranging from kidney fatigue to swelling and cramps, from headaches to loss of appetite, up to skin reactions.

Protein supplements are also not recommended for pregnant or breastfeeding women.

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