A probiotic blend improves defecation, mental health, and productivity in healthy Japanese volunteers under stressful situations

We investigated whether a blend of probiotics (KABP-021, KABP-022, and KABP-023) improved diarrhea-related problems in healthy Japanese adults who routinely lived under stressful conditions. Twenty-six females and 34 males were divided randomly into the probiotic and placebo groups in this double-blind, placebo-controlled, parallel-group comparison study. All participants ingested 1 capsule of probiotics or placebo per day for 4 weeks. Intervention with probiotics significantly reduced diarrhea-related problems assessed by the Izumo scale compared with placebo treatment (P < 0.001). In the Short Form-8 questionnaire, probiotic intervention improved mental component scores (P = 0.002), role emotional scores (P = 0.002), and mental health scores (P < 0.001). Treatment with probiotics also reduced the effects of diarrhea on daily activities (P < 0.001) and overall working habits (P = 0.010), including missing work (absenteeism) and impaired productivity (presenteeism), as assessed by the Work Productivity and Activity Impairment Questionnaire: General Health. Furthermore, there was a correlation between improved scores for diarrhea on the Izumo scale and increased abundance of Faecalibacterium, a butyric acid-producing bacterium, in the gut in the probiotic group (P = 0.047), whereas no such a correlation or trend was found in the placebo group. Our strategy of supplementation for 4 weeks with a specific blend of probiotics reduced diarrhea-related symptoms and may improve the mental health and daily activities of healthy individuals under stress.