Alteration of gut microbiota composition in patients with prediabetes and type 2 diabetes mellitus

Prediabetes is a risk factor for the development of type 2 diabetes mellitus (T2DM) and its complications. The prediabetes and diabetes mellitus prevalence has increased dramatically in recent decades. It is known that unhealthy diet and sedentary lifestyle promote the T2DM occurrence. However, more and more attention has been paid to the role of gut microbiota in the carbohydrate metabolism disorders pathogenesis and progression recently. The gut microbiota plays a key role in metabolism, immunomodulation and overall human health. Changes in the gut microbiota composition are associated with many diseases, including impaired fasting glucose, impaired glucose tolerance, increased insulin resistance and chronic low-grade inflammation. The review purpose is to consider the gut microbiota composition changes in patients with prediabetes and T2DM and its effect on metabolism. The review will also highlight the role of factors such as diet, exercise, taking metformin, glucagon-like peptide-1 receptor agonists (GLP-1 RA), probiotics, and synbiotics in changing the gut microbiota composition. Several studies confirm that structural and functional changes in the intestinal microbiota are present not only in T2DM, but also in prediabetes. These data suggest that the gut microbiota may be a target for new approaches to prevent the T2DM development. Modulation of gut microbiota with probiotics, synbiotics may have positive effects in the treatment of T2DM and related complications, but more studies are needed.