Relationship between taste sensitivity and oral microbiota composition : exploring their role in obesity development

Obesity in childhood and adolescence is considered the most prevalent nutritional disorder, in which diet and related eating behaviors represent important factors of influence. Although many aspects contribute to eating behaviors, taste is considered the main predictor. It has been suggested that obese subjects might have a reduced or distorted taste sensitivity that could increase the willingness to ingest foods that involve greater stimulation of the taste and oral somatosensory system. Recently, it has been suggested that oral bacteria could have a direct role in obesity development and a relationship between taste sensitivity and oral bacteria was proposed. In this context, the aim of the present study was to investigate the relationship among aspects potentially affecting weight gain , especially sensory perception and oral microbiota composition, in obese (OB) and normal-weight (NW) children and adolescents. In a cross-sectional study thirty-four OB (BMI ≥ 95th percentile; 45% F) and thirty-three NW subjects (56% F) aged between six and fourteen years old were recruited. Taste ability was assessed through gustatory function screening (using the ‘Taste Strips’ method) and Fungiform Papillae count. Unstimulated whole saliva samples were collected and the bacterial composition of saliva was determined by 16S rRNA gene profiling. Results showed that OB subjects presented a significantly lower ability to identify the correct taste qualities and were characterized by a greater number of FP/cm2 compared to NW subjects. The structure of the bacterial consortia, at the phylum level as well as at finer taxonomic rankings, resulted very similar in the two groups. Nonetheless, the levels of Bacteroidetes were different in children and adolescents characterized by a greater ability in identifying the bitter taste, independently of their nutritional status. The potentiality of this multidisciplinary approach could help to better understand and deepen the sensory-driven and microbiological factors related to weight gain.