Журнал «Здоровье ребенка» 3 (46) 2013

Current data suggest that in human organism there are 10¹⁴ of different microorganisms, mainly in the intestine. In this case of normal microflora plays an important role in metabolism, immune resistance and digestion in a whole. The priority significance in the functioning of endoecological system belongs to prebiotic properties of carbohydrates.

Dietary fibers have a wide range of effects on the human body: stimulate intestinal peristalsis and react its motor function, reduce the absorption of cholesterol and fatty acids, absorb toxic products, foreign substances, carcinogens, radionuclides, and some proteins, fats and carbohydrates in the intestines; stimulate processes of bile secretion, prevent its assimilation and normalize the function of the biliary tract, create feeling of fullness and reduce energy consumption, form and increase fecal masses, dilute intestinal contents, help to excrete from the organism the products of incomplete digestion of nutrients, slow down glucose absorption from the intestine, which leads to reduction in insulin requirements, reduce the content of glucon, immunoreactive insulin blood levels, increase sensitivity of tissue receptors to insulin and tolerance to carbohydrates, reduce cholesterol synthesis and reduce blood cholesterol levels; positively impact on intestinal microflora, accelerate the processes of fat metabolism in the organism.

Traditional sources of dietary fibers are cereals, legumes, vegetables, roots, berries, nuts, citrus fruits, mushrooms. Most fibers are found in bran of whole grains, shelling beans, peel of vegetables (beets, carrots, squash, eggplant, cabbage) and fruits (apples, plums, apricots, strawberries, currants, raspberries, figs, cranberries, mountain ash, plums, gooseberries, dill and raisins). Among the green vegetables significant amount of dietary fiber is found in green vegetables (spinach, lettuce, chicory, leeks, asparagus beans). Cooking and heat treatment affect their number: they are not saved after removing the pulp when cooking juices, after heat treatment more than half of cellulose is lost. Alternative sources of dietary fiber in the modern period are: seaweed, corn and reed stalks, grass, and wood fiber. The main methods of commercial production of dietary fiber from the raw material is cleaning cereals or vegetables in neutral, acidic, neutral and acidic medium, or treatment with enzymes.

Intestinal microflora requires constant provision by carbohydrates. The greatest practical importance belongs to dietary fiber, polymers of monosaccharides and their derivatives which are contained in plant foods and digested in the stomach and intestines. However, some of their parts (pectin, hemicellulose, gums, mucus) are dissolved by intestinal microbes. Prebiotic properties of carbohydrates enhance the biological effects of endoecological system: regulation of proliferation and differentiation of epithelium, antibacterial activity, blocking adhesion of pathogens to the epithelium, increased local immunogenesis and nonspecific immunostimulation.

Development of qualitative and quantitative disorders of healthy symbiotic intestinal microflora causes metabolic and immunological disorders. At present the priorities of preventive medicine is to prevent the development of disease on pre-nosological level. In this regard, the leading situation of hygienic early diagnostics is that complete or partial elimination of bifidobacteria leads to the dominance of opportunistic microorganisms. Hygienic early pre-nosological diagnostics of dysbiotic phenomena is based on the following criteria: reduction of bifidobacteria, lactobacilli and Bacteroides, changing the balance between aerobic and anaerobic microflora, changing the ratio between microbial populations of obligate and facultative representatives of normal microflora; appearance of hemolyzing Escherichia  and staphylococci, increasing the total number of E. coli with depressed biological properties; unprofitable colonization of the small intestine.

The leading risk factors of dysbiotic phenomena are as follows: iatrogenic (antibiotics, medicines, diagnostic and therapeutic procedures), biological (viruses, bacteria, fungi, protozoa, rickettsia), chemical (xenobiotics of different nature) and physical (radiation, electromagnetic fields, air ions, noise, vibration) factors. Nutrition disorders, internal diseases, psychosocial conditions are also promote development of dysbiosis. Mechanism of dysbiosis development under these factors schematically looks as follows: stress syndrome – changes of homeostasis – disorders of the metabolic conveyor – change of value in microbial community – the development of dysbiosis.

Thus, prebiotic properties of carbohydrates determinate formation of health by synthesis of two types of metabolites. The first are synthesized by macro-organism (dextrins, maltose, dextrose, fructose, maltoptoza). The second type of metabolites (butirat, lactate, formate, propianat, acetate, muramid dipeptide, etc.) are synthesized by intestinal microflora. It provides the strengthening of local immunogenesis, antibacterial effect, non-specific immune stimulation. The leading risk factors of dysbiosis are iatrogenic, biological, chemical and physical factors, nutritional disorder. Prospects for the further research are related to the justification children food rations with prebiotic orientation based on selective use of products and foods with a high content of dietary fiber.