Probiotics in current medical practice: From myths to scientific evidence

In recent years, probiotics have gained increasingly greater attention of clinicians due to their use in the prevention and treatment of multiple diseases. At the same time, the number of myths imposed by different media is also growing. The main mechanisms of action of probiotics include improvement of the mucosal barrier function, direct antagonistic activities against pathogens, inhibition of bacterial adhesion and invasion in the intestinal epithelium, enhancing of immunity and central nervous system regulation. Normal gut microbiota plays a critical role in maintaining the human health. Gut microbiota imbalance and dysbiosis may give rise to such diseases as infections, autoimmune diseases, allergies, etc. Probiotics seem to be a promising approach to the prevention and even relief of symptoms of such clinical conditions as an adjuvant therapy by preserving the normal gut microbiota balance and boosting the immunity. The present review refutes common myths that prevent from recommending and using probiotics for various indications. To date, stronger evidence in favour of their clinical use is provided in the prevention of gastrointestinal disorders, antibiotic-associated diarrhea, allergy and respiratory infections. Numerous in vitro studies, preclinical and clinical trials showed the significance of the human microbiota, improvement and restoration of its functions by probiotic treatment. In this review, we tried to summarize current knowledge on probiotics’ use and therapeutic potential in different diseases of not only digestive system, but also outside the gastrointestinal tract.