General principles or laws of physiological nutrition of children

The principle of physiological adequacy of nutrition is the maximum degree of compliance of a food product with the capabilities of biting, chewing, swallowing, digestion, absorption and metabolization that a child of a given age has. It is very important to rely on well-studied natural patterns of the emergence of certain fermentation capabilities, immunological tolerance or inclusion in plastic processes. The concept of "adequacy" should include the immunological, mechanical properties of the product, its osmotic and taste characteristics. In practice, one also encounters "pseudoadequacy" - the apparent good tolerance of a particular food product.

It is necessary to emphasize this because children have great adaptive plasticity and are able to quickly and effectively adapt to "tolerate" a variety of food products. It can also be said that such adaptive plasticity is used in age physiology itself. The swallowing movements of the fetus with the ingestion of amniotic fluid that occur in the middle stages of gestation are a new stage of adaptation of the gastrointestinal tract with all the enzymatic systems of parietal digestion to future enteral milk nutrition. The same very smooth system of re-adaptation measures is used by the family and the pediatrician, regulating the gradual accustoming of the child to thick food when introducing complementary foods. But it is often necessary to state that children tolerate relatively rough dietary "experiments" without rough clinical breakdowns. There are observations of a completely calm reaction of children of several days or weeks of life to supplementary feeding with simple milk formulas, including whole milk or kefir, or to the early introduction of complementary foods based on gluten-containing cereals. Children are forced to obey and trust adults. However, such adaptation always represents a "zigzag" on the path of normal development. Such phenomena can be presented as particular manifestations of the general phenomenon of "adaptative development".

Premature emergence or enhancement of a function due to forced adaptation, on the one hand, leads to a relative lag in other directions of growth and differentiation, creating heterochronies of development, and on the other hand, to the final incompleteness of the formation of the function that was induced prematurely. This is one of the general laws of the nature of development. Artificial feeding is aphysiological for a child, it inevitably generates significant biological characteristics and changes in the spectrum of morbidity in the subsequent life of older children, adolescents and adults. These include such as hyperlipidemia, hyperinsulinemia, obesity and obesity, early atherosclerosis, behavioral disorders and the ability to form relationships, reduced learning ability.

At present, there is no doubt that breastfeeding cannot be considered as an exclusively nutrient and energy supply. As an equivalent and continuation of the umbilical cord connection of the intrauterine period, breast milk carries the widest range of regulatory and information carriers - hormones, biologically active substances and stimulators of differentiation of individual systems and organs, factors of immunological regulation and tolerance. Of great importance in natural feeding is the unique system of psychological and social imprinting in the process of breastfeeding, as well as the specific mechanism of sucking effort and tension. At the same time, being only a component of the complex effect of breastfeeding, the phenomenon of nutrition through mother's milk in itself is the "gold standard" of dietetics. In the "lessons" of breastfeeding, many basic principles of developmental dietetics can be revealed.

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The principle of sufficiency of energy supply

It may seem somewhat artificial, as it repeats the formula of the main purpose of nutrition for a child of any age.

Nutrition or its energy characteristics must be sufficient to cover all energy expenditure and ensure growth. In any situation, the child's main functions - weight gain, growth and differentiation - must be performed. Children (like pregnant women) should never lose weight or stop gaining weight. Emphasis on the energy security of the child's nutrition is necessary due to the fact that it requires special attention or support from the doctor. In the general structure of energy expenditure, which includes the basal metabolism, the specific dynamic effect of food, the costs of physical activity, stress, losses associated with excretion, the costs of growth and development are always the last in order. Moreover, we can also say that they are covered "on a residual basis", after all other energy debts have been compensated. The more "other" costs increase, the higher the risk of under-provision of growth and development.

It is easy to imagine that during those periods of childhood when energy expenditure for growth becomes relatively small (5-8% of the total energy balance), even a less pronounced decrease in appetite or an increase in competing energy expenditure can cause a child to lag behind in growth and development.

Examples can be found in any situation with an increase in physical activity. For example, forcing the training regime in a sports section is accompanied by a decrease in the growth rate or even its cessation.

An illustration of this is the entire clinical picture of childhood diseases, where a decrease in the rate of growth and increase in body weight can be observed against the background of feverish conditions and stress, even with the preservation of appetite and the child's usual diet. Any, including the most objectively forced, energy deficiency in nutrition, creating restrictions on the rate of growth, is a significant alteration of development and creates irreversible changes in its qualitative characteristics. The pediatrician must understand the "systematic" nature of growth processes. It is unlikely that a "shortage" of 1-2 cm of growth in a certain age period should be considered a dramatic event. But this insignificant lag in skeletal growth can reflect a much more significant "shortage" in the mass of the brain, lymphoid and hematopoietic tissue, parenchymatous organs, reproductive organs in adolescents, etc. From the standpoint of "systematic growth", any risk of a decrease in the normal rate of development, and especially its actual decrease in a child, is an extremely significant pathological condition. It requires immediate intervention both in the content of the diet and in the methods of its "delivery" to the sick child. All these deviations are even more significant during those periods of growth when the intensity, speed and systematicity of growth-differentiation processes are maximal, i.e. in the intrauterine period or postnatally, as applied to children born with low body weight.

The principle of "multicomponent nutritional balance"

It is a continuation and confirmation of the concept of balanced nutrition, introduced into dietetics by A. A. Pokrovsky. To create the whole variety of organic molecules or structures, it is necessary to use a wide range of starting materials at once. A simplified approach to the diet with limited control of its nutritional value (like "energy and B: F: U") means our simplistic and negligent attitude to the development of children. Without including calculations of iodine or iron provision in the control of the diet, we do not consider it necessary to care about the development of intelligence and memory, neglecting the analysis of zinc provision in boys, we condemn them to problems of growth, puberty and fertility, without calculating the calcium "ration", we form juvenile osteochondropathy and osteochondrosis of adults.

There are many problems in implementing the principle of multi-component provision related to the proof of the essentiality of a particular nutrient for children. First of all, this concerns the so-called conditionally essential food substances, the range of which for newborns or sick children is often significantly wider than for adults. These may include such nutrients as long-chain polyunsaturated fatty acids (arachidonic, eicosapentaenoic and docosahexaenoic), carnitine, choline, inositol, cysteine, tyrosine, arginine, glycine, and nucleotides. In this case, the conditionality of essentiality is determined in relation to the state of complete health of children. However, in any unfavorable situation in a child's life, especially with infections, it is the provision of conditionally essential nutritional factors that can be decisive in reducing the severity or risk of chronicity of the disease. An adequate selection of nutrients for multicomponent nutrition is usually carried out taking into account the “gold standard”, i.e., human milk.

A significant problem is the transition from a list of many standardized nutrients to specific diets taking into account the possibility of fractional or periodic intake of a nutrient with food, its short-term or long-term deposition, and the level preceding the deposition of the nutrient.

It is the lessons of natural feeding that have become the basis for numerous developments of "recommended consumption rates", numbering up to 40 standardized nutrients. They also form the basis for the development of new baby food products and the corresponding international requirements or "codes" for the composition of these products.

At present, it is not possible to evaluate the diet manually for the entire range of nutrients. The only possibility and prospect is automated analysis systems based on modern computers.

The principle of "nutrient supply"

Any event in development, primarily cell division, cytoplasmic growth, differentiation of cellular structures, can adequately occur only in the presence of all chemical substances, both those involved in tissue "new constructions" and those participating in the regulation of plastic processes. Thus, provision must necessarily precede and in advance accompany all processes of growth and development. Obviously, with a borderline or relatively insufficient supply of nutrients in children, there will always be a contradiction between their direction to plastic processes and the necessary provision of active life or stress. In growth physiology, there is a system of insurance for such emergencies through the use of various tissue depots. In the absence of a sufficient nutrient depot, this competition most often leads to a deficit in the provision of development, to its alterations. Thus, the task of pre-provision emphasizes the importance of the processes of nutrient deposition, their vital importance for the quality of development. The principle of pre-provision can be illustrated especially vividly and convincingly by examples related to the nutrition of pregnant women. The most studied is iodine deficiency in the diet of pregnant women.

The spectrum of consequences of iodine deficiency during pregnancy

• Stillbirth.
• Congenital developmental anomalies.

Neurological cretinism:

• mental retardation;
• deaf-muteness;
• strabismus.

Myxedema cretinism (hypothyroidism, dwarfism):

• mental retardation;
• short stature, hypothyroidism;
• psychomotor disorders.

The table shows the results of the effectiveness of iodine supplementation by intramuscular administration (in oil or water solution) before conception or in the first weeks after it.

Preventive iodine administration before conception or during pregnancy and the incidence of cretinism in children

Indicator	Introduction of iodine
	Before conception	After conception
Total number of births	593	95
Newborns with cretinism	1	5
Frequency per 1000 live births	1.7	52.6

The data provided on iodine can be supplemented with numerous other examples of the importance of pre-supply in developmental dietetics. Convincing developmental and health disorders can also occur with many, more rarely observed nutritional deficiencies in pregnant women, such as copper.

Prenatal copper deficiency

Effects on the fetus and newborn

• Stillbirth or early neonatal death.
• Neurological disorders:
  • defective myelin synthesis;
  • hypoplasia of the cerebrum or cerebellum.
  • Changes in the cardiovascular system:
  • aneurysms and varicose veins;
  • fragility and fragility of blood vessels.
• Skeletal matrix changes:
  • abnormal collagen structure;
  • elastin abnormality.
• Energy metabolism disorders.
• Disorders of phospholipid metabolism.
• Slowing growth.

This principle to a certain extent falls outside the stereotypes of thinking and activity of doctors, focused on the establishment of a pathological condition and subsequent decision-making. Pre-provision, as well as all prevention through maintaining the development environment, must be carried out permanently in relation to each child, both sick and healthy.

The principle of provision for infants must also be interpreted in terms of a systemic understanding and absolute inseparability of the problems of feeding a child, the nutrition of a nursing mother during the period of breastfeeding, the nutrition of a pregnant woman, the nutrition of a woman (and a man to some extent) in the period of preparation for conception, the nutrition of women of childbearing age and adolescent girls.