The use of probiotics in the prevention of seasonal acute respiratory infections
The problem of seasonal incidence in children and adults with acute respiratory infections in recent decades has become increasingly important. This is due not only to an increase in the number of urban population and a naturally increasing frequency of contacts, but also to the nutritional characteristics of modern man. The diet of most residents in different countries of the world today is very different from the diet of generations who lived more than a century ago. When there were no technologies for long-term storage of finished products, the population ate foods rich in vitamins and sour-milk bacteria. Naturally grown vegetables, fruits and berries provided an adequate level of vitamin C, which plays a significant role in the immune response. In addition, for many centuries, fermentation or fermentation was used for long-term storage of products, resulting in food enriched with sour-milk bacteria. These microorganisms actively participated in the formation of microflora of the gastrointestinal tract and other human systems. It has now been proven that the complex of microorganisms not only plays an important role in the digestive processes, absorption of various substances, the synthesis of vitamins, but also forms an immune response. Recently, more and more people are beginning to think about the quality of food consumed, while before, attention was paid mainly to the taste and quantity of food. An analysis of the current information on the role of microflora indicates that dysbiotic disorders are one of the main reasons for the increase in the number of patients with recurrent acute respiratory infections. Of greatest importance is the problem in pediatrics. Pneumonia remains the leading cause of death in children under 5 years old. Infections of the respiratory tract, among which influenza remains in first place in the number and severity of complications, are one of the main causes of adult disability worldwide.
Numerous studies show that the main representatives of the normoflora – bifidobacteria and lactobacilli play an important role in the formation of immunity, both acquired and innate, as well as in modulating it in response to an infectious process. Microflora interacts with dendritic cells – antigen-presenting structures in the intestine that regulate the activity of acquired T- and B-cell immunity, macrophages, and membranous cells (M-cells). The result of the interaction is the formation of cytokines and antibodies by lymphocytes, in particular the production of immunoglobulin A (IgA) by the plasmocytes, which is the basis of the local immune defense of the mucous membranes. In addition, probiotic strains inhibit apoptosis by activating the antiapoptotic Akt protein kinase, which stabilizes and improves the condition of the epithelium.
Currently, it is well known that different types of probiotics have their own characteristics, depending on which they can exhibit different properties. The results of most experimental and clinical studies suggest that only certain strains stimulate intestinal dendritic cells, due to which regulatory T cells (Tr cells) are formed and interleukins-10 are produced that contribute to the formation of immunological tolerance to their own microbiota and food antigens. This selectivity is due to the ability of some probiotics to bind adhesion molecules within the cell, which facilitates the formation of Tr cells by dendritic cells. Under the influence of probiotics, there is a change in the balance of adaptive immunity regulated by dendritic cells, due to which there is a decrease in the pro-inflammatory response and IgE synthesis. According to the journal Therapeutic Advances in Gastroenterology, studies have been conducted that have shown that some genetic elements of the intestinal microbiota can functionally complement the genes of intestinal cells necessary for its normal functioning.
After the birth of a child, bacteria colonize the entire surface of the intestinal mucosa. The nature of the composition and concentration of the intestinal microbiome during the period of the first childhood is very different from that of the adult microbiome, therefore achieving optimal balance of the intestinal flora, providing an immune response and at the same time immunological tolerance in the first 3-4 years of a child’s life, is crucial for maintaining health at throughout all subsequent years. Given the changes in the nutritional nature of the population, the need for the use of probiotic strains for the prevention of repeated acute infectious diseases and allergic pathology is now obvious, which in turn is a factor that increases susceptibility to pathogenic microorganisms.