Intensive, prolonged exercise is known to induce gastrointestinal disorders such as diarrhea, with gut dysbiosis suggested as being one of the causatives. In the present study, we wanted to investigate the relationship between intensive exercise and the gut microbiota status. To that end, the microbiota, the moisture content and the bacterial metabolites (e.g., organic acids) of female endurance runners (n = 15) and those of non-athletic but healthy, age-matching female controls (n = 14) were compared. The analysis of the gut microbiota analysis showed that, unlike control subjects, female endurance runners had distinct microbiotas, with some bacteria found in higher abundances likely being involved in gut inflammation. The concentration of succinate, a gut bacterial metabolite regarded as undesirable when accumulated in the lumen, was significantly (p<0.05) higher in the female endurance runners. Faecalibacterium, that was significantly (p<0.05) abundant in female endurance runners, can produce succinate in certain environments and hence may contribute to succinate accumulation, at least partly. The present work suggested that the gut microbiotas of female endurance runners are seemingly dysbiotic when compared with those of control subjects. Further investigation of the mechanism by which intensive, prolonged exercise affects the gut microbiota is recommended.

Alcohol‐associated liver disease (ALD), including alcoholic fatty liver, is a serious problem in many countries, and its economic costs to society are enormous. There is evidence indicating the relations between gut environments and liver disease, and thus, improvement of gut environment is expected to be an effective approach for ALD prevention. In this study, we explored the preventive effect of partially hydrolyzed guar gum (PHGG) on ALD focusing on the gut–liver axis. Two weeks of PHGG pre‐feeding suppressed the liver fat accumulation in the experimental binge alcohol model mouse. In cecal microbiome, PHGG pre‐feeding increased beneficial Bifidobacterium with its metabolite acetate concentration and suppressed the alcohol‐induced increase in the potential pathobiont Streptococcus . PHGG pre‐feeding increased colonic gene expression of angiogenin genes, which act as antimicrobial peptides and decreased expression of genes for mast cell protease, which suggests a potential involvement in leaky gut. Correlation network analysis based on evaluated parameters revealed four relations worth noticing. (i) The abundance of Bifidobacterium positively correlated with cecal acetate. (ii) Cecal acetate negatively correlated with Streptococcus via colonic angiogenin expression. (iii) Streptococcus positively correlated with liver fat area. (iv) Cecal acetate had direct negative correlation with liver fat area. Considering these relations comprehensively, acetate produced by Bifidobacterium may be a key mediator in ALD prevention; it inhibited growth of potential pathobiont Streptococcus and also directly regulated liver lipid metabolism reaching through portal vein. This study demonstrated that regularly intake of PHGG may be effective in reducing the risk of alcoholic fatty liver via gut–liver axis.

Office workers often experience gastrointestinal problems such as constipation, which can reduce labor productivity and quality of life. This study investigated the effects of continuous partially hydrolyzed guar gum (PHGG) intake on the gut microbiome, health status, and labor productivity of Japanese office workers. In this open-label, single-arm trial, 136 employees of Yoshinoya Holdings Co., Ltd. consumed 6 g of PHGG daily for two months. Outcome measures included gut microbiome composition (16S rRNA sequencing), body composition (InBody 380N), gastrointestinal symptoms (Izumo scale), sleep quality (OSA-MA), and labor productivity (WHO-HPQ). PHGG intervention was accompanied by specific genus-level alterations in the gut microbiome characterized by the enrichment of beneficial taxa including Bifidobacterium, Faecalibacterium, and Prevotella, despite no significant overall shift in beta-diversity. Notably, exploratory subgroup analysis indicated shifts in enterotypes from profiles previously associated with disease risks toward those more prevalent in healthy populations. Physiologically, whole-body phase angle, an indirect parameter associated with cellular status and fluid distribution, slightly increased during the study period. Furthermore, favorable changes were observed in absolute presenteeism, gastrointestinal symptoms and subjective sleep quality. Although verification with a more robust study design is necessary, these findings suggest that PHGG may be associated with positive shifts in the well-being and labor productivity of office workers.