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 (center dot 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- center dot 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 center dot 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.