2019 Volume 2019 Issue 29 Pages 101-111
Purpose In previous studies, brown rice eaters had regular bowel movements and the monitoring of their stool microbiota showed a normal microbial diversity profile. A subpopulation among participants to the GENKI I cohort study was studied to explore the relationship between the subjective feeling of being healthy (positive emotions) and the profile of the intestinal bacterial flora.
Method Ninety-seven participants who had been enrolled in the GENKI I Study had their fecal bacteria analyzed at phylum and genus levels by 16S rDNA amplicon sequencing, and correlations with epidemiological data were examined. The subjective feeling of being healthy was measured by a self-rated assessment tool.
Results Participants scoring high on the subjective sense of health showed a higher abundance of Roseburia in their stools (ｐ= 0.013). Eaters of brown rice diet also tended to carry more butyric acid-producing bacteria, especially of the Faecalibacterium prausnitzii (ｐ=0.026). The proportion of bacteria producing short-chain fatty acids such as Bilophila (ｐ=0.048) was also higher in brown rice eaters.
Discussion It has been reported that butyric acid and derived metabolites produced by intestinal bacteria could affect emotions mediated through the gut-brain nervous system. The subjective feeling of being healthy has complex determinants. Butyrate-producing bacteria could be one of them. However, a limitation of this study is that being healthy was a criterion for being enrolled in the GENKI cohort. A selection bias might therefore have influenced the observed results. Our hypothesis should thus be further explored through an intervention study.
Conclusion We have identified a possible correlation between a high subjective sense of health and the presence of butyric acid-producing bacteria in the gut. In addition, Faecalibacterium prausnitzii was more abundance detected among brown rice eaters. Participants scoring high on the subjective sense of health showed a higher abundance of Roseburia in their stools. It was revealed that the occupancy rate of the short - chain fatty acid - producing bacteria, such as Blautia, and Bilophila is high.
