We have been coming up with several interesting questions lately about proteins and their intake.
With this in mind, we have decided to write a series of themed articles to clarify some issues and help you choose and maintain a healthy diet.
The proteins in the body are not present as stable entities, but are subject to continuous turnover; they are in fact continuously demolished and replaced by new and similar protein molecules through a process known as protein turnover.
Humans and animals therefore constantly need proteins and amino acids to survive. Introduction with food is essential to ensure a correct response to protein needs and maintain good health.
Meat, fish, eggs, nuts, milk and derivatives are all foods with a high content of noble proteins as they are rich in essential amino acids.
Rice, wheat, cereals and legumes contain a fair amount.
Fruits and vegetables are foods that are deficient in this nutrient.
Dietary proteins are defined as having a high biological value (BV) or noble proteins if they contain all the essential amino acids in an adequate proportion for the body.
The efficiency and nutritional quality of food proteins was also assessed in terms of its digestibility or assimilable.
In fact, during digestion, some amino acids can be lost or eliminated without real assimilation. This feature further influences the nutritional value of the food.
The protein that has a perfect balance between absorbed amino acids and eliminated amino acids has a biological value of 100 or higher.
The reference food protein in this sense is that of egg which has a VB equal to 100%. However, the highest VB is due to whey protein with a value of 104.
Casein, Fish, Beef
In general, we can define animal protein sources as noble, that is, with high biological value; it is enough to remember that the first protein source of life is represented by milk.
The sources of vegetable proteins are less noble.
Cereals, for example, contain little lysine while legumes are low in methionine.
However, the association of these two foods (e.g. pasta and beans) is able to ensure the needs of the reciprocal amino acids, as the limiting amino acid of a protein, that is the one present in the least quantity, is compensated by its greater availability. in the other; in this case we speak of complementary proteins.
Diets that provide incomplete protein can lead to malnutrition.
For this reason, nutrition must be balanced, not only in terms of calories, but also in the qualitative composition of the elements that constitute it.
It is of fundamental importance to introduce the right amount of protein in the diet every day, necessary to maintain good health.
This amount is called protein requirement.
It is individual and complex to define exactly in numerical terms; in fact, it depends on various variables, such as lifestyle, body composition and the amount of dietary protein introduced.
There are also physiological conditions that increase protein requirements such as the stages of growth and development, pregnancy and breastfeeding, the presence of trauma, burns, surgery, convalescence and intense sporting activity there.
To give an example, a sedentary 60 kg person, who performs office work and does not engage in any physical activity, should consume 45 to 60 grams of protein per day.
Type of Person
Proteins (g per kg of body weight)
0,75 - 1 g/kg
Active, Endurance Sports
1 - 1,5 g/kg
Children, pregnant / breastfeeding women
1,5 - 2 g/kg
Competitive athletes, strength sports
> 2 g/kg