We are accustomed to rush smart words, like food, energy, biological value and are confident that all this relates to what interests us the most - calories . But in fact, nutrition studies not only the calorie content of food. First of all, the basic, the broadest concept in relation to products is nutritional value.
What is the nutritional value?
The nutritional value of food is a very broad concept that reflects the fullness of the useful properties of the product. Including, and the degree of replenishment of the needs of the human body with this product, as well as the energy released during its oxidation.
Nutritional value is determined by the chemical composition of this product, and the composition, in turn, predetermines not only the utility, but also the taste, aroma, color of the product. Thanks to the nutritional value, we can calculate the ratio of calorie intake, digestibility, and, of course, the quality of food.
There is even a classification of the nutritional value of the products. All food products are divided into two groups - organic and mineral substances. The organic substances in the products include:
- proteins;
- carbohydrates;
- fats;
- vitamins;
- acids;
- enzymes.
Mineral substances include:
- water;
- macronutrients;
- microelements.
In order not to calculate independently the nutritional value of each eaten product, special tables are created - the best assistants of those who follow their food.
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Energy value of food products
This is the very thing we love about caloric content. Food is the only source of energy for a person, so calorie needs to be considered as a process of obtaining energy to meet the needs of the body.
The energy value of food is the energy that can be released from products when they are oxidized in the human gastrointestinal tract. We emphasize - "can", but not necessarily free. There is a theoretical and actual energy value.
The theoretical energy value of food is the amount of gross energy that is released when food is oxidized. Pay attention to the following indicators:
- 1 g of fat - 9 kcal;
- 1 g protein - 4 kcal;
- 1 g of carbohydrates - 3.75 kcal.
But the actual value is that we get net. We do not assimilate any of the substances by 100%. So, proteins are assimilated by 84.5%, fats - by 94%, carbohydrates - by 95.6%. As a result, in order to calculate how much and what we get, we must multiply the gross by a factor in percent:
- 1 g fat - 8.46 kcal;
- 1 g protein - 3.38 kcal;
- 1 g of carbohydrates - 3.58 kcal.
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Biological value of food products
How much the product is valuable to our body depends on the presence in its composition of irreplaceable components that are not synthesized in our body, or are produced slowly and under certain conditions.
That is, the biological value of food is characterized by the degree of conformity of food to our needs.
For man there are several categories of irreplaceable substances, whose biological value, respectively, is the highest:
- 8-10 amino acids - 8 amino acids are indispensable for us throughout life, and histidine and cystine are indispensable for infants.
- 3-5 polyunsaturated fatty acids;
- all vitamins;
- almost all mineral substances (including water);
- substances with high biological activity - phospholipids, glucoproteins, protein-lecithin complexes.
Thus, in order for the nutrition to correspond to both energy and biological value, we must follow not only the caloric content of our diet , but also the contents of all indispensable components for our people.