Peculiarities of nutrition in children of early age

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For each period of childhood, as it is known, is characterized by certain features of the anatomical structure, physiological functions and metabolism. Digestive processes in children also have some special features.
The food, once in the digestive tract of a child undergoes a series of complex reactions, as a result of which it becomes a source of energy and plastic material for building structural elements of tissues.
The process of assimilation of food complicated and, according to modern concepts, consists of consecutive stages.
The process of digestion begins in the mouth and continues in the stomach and intestines is the I stage of assimilation. Food is subjected to mechanical and chemical influences, in which food substances are processed and converted into a certain chemical compounds. After this comes the II stage of assimilation is the process of absorption of nutrients in the blood; stage III - a cellular nutrition when that absorb nutrients penetrate the cell and subjected to complex biochemical changes in the intracellular structural formations. And finally, IV stage - removal of the products of metabolism of nutrients from the body.
According to the concept A. A. Pokrovsky (1966, 1971), one of the most important conditions for proper assimilation of food is the compliance of the relationship between the enzyme systems of the body and chemical structure of input of food. For optimal processes of assimilation necessary that the food was adequate to level of development, and functional maturation of the digestive system and enzyme systems of the body of the child. In newborns and children of the first months of life digestive system is still morphologically immature, and its functionality is reduced. In the process of growth, gradual improvement of the structure and function of digestive glands, increase the possibility of adaptation to a qualitatively different food [Zentre M, 1986].
Digestion begins in the mouth. Here the food is short and is exposed mainly mechanical processing. From the chewed food in the mouth formed a food lump. The important role in realization of these processes is played by the saliva produced by the salivary glands.
In newborns secretion of saliva minor, from 3 to 6 months of life salivation in infants is significantly intensified. The number of saliva depends on the nature of breastfeeding. It increases with consumption and especially when artificial feeding [Kharkiv R. M., 1978].
In early postnatal period saliva also promotes close contact breast nipple mother tongue and mucous membranes of the mouth of a child. In the mouth of the child are created vacuum conditions that facilitate the sucking. Saliva mixed with milk, promotes formation in the stomach is very soft and friable bunches of caseinto facilitate digestion. During the act of sucking the amount of saliva increases. So, in newborns speed select it on an empty stomach is 0,01-0,1 ml/min, and sucking and-0.4 ml/min
Saliva contains enzymes (amylase, peptidase and others) and bactericidal substances (lysozyme). From all components of saliva largest value in the digestion has amylase is the enzyme that breaks down carbohydrates (enzyme molecule starch and glycogen to stage three - and disaccharides). Newborn amylase activity is very low (341 ± 54 ME, Wohlgemuth). For 1-2 years, activity is increasing, reaching levels of adult (857 ± 164 ME) [Obolenskaya A. Century, 1981]. The amylase activity depends on the nature of breastfeeding: when breastfed enzyme activity is lower than in artificial.