Inorganic nitrate: A potential prebiotic for oral microbiota dysbiosis associated with type 2 diabetes.

Oral microbiota dysbiosis, concomitant with decreased abundance of nitrate (NO3-)-reducing bacteria, oral net nitrite (NO2-) production, and reduced nitric oxide (·NO) bioactivity, is associated with the development of cardiometabolic disorders. Therefore, restoring the oral microbiome to a health-associated state is suggested as a therapeutic approach to potentiate the NO3--NO2--·NO pathway and provide a backup resource for insufficient NO production in conditions including cardiovascular disease and type 2 diabetes mellitus (T2DM). The current review discusses how inorganic NO3- can improve the oral microbial community in patients with T2DM and act as a prebiotic. Both animal and human experiments indicated that inorganic NO3- modulates the oral microbiome by increasing the abundance of health-associated NO3--reducing bacteria (e.g., Neisseria and Rothia) and decreasing the plenty of species Prevotella and Veillonella, leading to oral NO2- accumulation and improved systemic ·NO availability. Supplementation with NO3- reduces caries- and periodontitis-associated bacteria and the pathogenic genus related to insulin resistance and glucose intolerance. In addition, inorganic NO3- may provide a more optimal environment for NO3- reductase activity in the oral cavity, as it increases salivary flow rate and prevents decreased pH by inhibiting acid-producing bacteria.