eng Science and Education Publishing Journal of Food and Nutrition Research 2333-1240 2024-04-06 12 4 168 172 10.12691/jfnr-12-4-1 JFNR20241241 article Kanako Sugawara k.sugawara.ye@juntendo.ac.jp 1 Ailing Hu 1 Takuji Yamaguchi 1 Masahiro Tabuchi 1 Yasushi Ikarashi 1 Hiroyuki Kobayashi 1 Personalized Kampo Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan Bananas, rich in prebiotics, dietary fibre, oligosaccharides, vitamins and minerals, have positive effects on gut health. However, their impact on oral cavity-derived gut microbiota and the intestinal environment remains unclear. This study investigated changes of the gut microenvironment and oral cavity-derived gut microbiota populations induced by banana intake. Twenty-six healthy women were instructed to consume two bananas per day for 2 weeks. We measured urinary indoxyl sulfate levels (a general gut microenvironment index) and the proportion of oral microbiota species within the gut microbiota before and after the 2-week banana consumption period. Banana intake significantly reduced urinary indoxyl sulfate levels. Additionally, participants aged < 40 years showed decreased indole levels, while no significant change occurred in those aged 40 years. The total number of bacterial species decreased due to banana intake. However, oral microbiota and Porphyromonas spp. populations remained unchanged in all participants. Nevertheless, participants with a high urinary indoxyl sulfate levels before banana intake showed slightly reduced oral microbiota and Porphyromonas spp. prevalence after banana intake, along with significantly lower urinary indoxyl sulfate levels. Therefore, the decreases in urinary indoxyl sulfate and the prevalence of oral cavity-derived bacteria and Porphyromonas spp. indicates the regulatory activity of bananas on gut microbiota. https://pubs.sciepub.com/jfnr/12/4/1/jfnr-12-4-1.pdf oral bacteria gut microbiota Porphyromonas spp indoxyl sulfate banana intake