Unravelling the interplay between the oral microbiota and the salivary environment: links with body mass index and taste perception.

Taste perception, a key determinant of eating behavior, arises from a complex interaction between the oral cavity and the brain. Increasing evidence suggests that oral microbiota metabolism may contribute to this process. This study aimed to advance understanding of the connection between salivary bacteria and taste perception in a cohort of 108 adults by exploring the relationship between microbiota profile (16S rRNA gene amplicon sequencing), their metabolic products (lactate, acetate, propionate, and butyrate) and the salivary environment (flow rate, total protein content, antioxidant capacity) with taste perception, while accounting for biological variables (body mass index and age). The results identified 39 bacterial genera associated with the concentration of salivary acids, most of them related to oral diseases like periodontitis and dental caries. The association between short-chain fatty acids (acetate, propionate, butyrate) and salivary protein content suggests they may originate from the degradation of salivary proteins. Additionally, individuals with overweight presented higher salivary organic acids and protein content levels than the normal-weight counterparts. Twenty-nine bacterial genera were associated with the perception of basic tastes. Although taste-specific associations varied among taste modalities, members of the Clostridia class were consistently linked to all tastes. While heightened sweet, salty, and sour taste perceptions appeared to be linked to bacterial consortia associated with lower concentrations of salivary organic acids, bitter taste was associated with bacteria positively related to acids and inflammation. These findings underscore the complex interplay between oral microbiota metabolism, salivary composition, and taste perception, with potential implications for dietary behavior.