Bifidobacterium bifidum G9‐1 Intake Improves Gastrointestinal Symptoms in Type 2 Diabetes Mellitus: An Open‐Label, Randomized Controlled Trial (Binary STAR Study)

ABSTRACT Aims To evaluate the effects of probiotics Bifidobacterium bifidum G9‐1 (BBG9‐1) on gastrointestinal symptoms in patients with Type 2 diabetes mellitus (T2DM) with diarrhoea or constipation. Materials and Methods In a 12‐week open‐label randomised controlled trial, 100 participants were randomized 1:1 to a control or BBG9‐1 group, with 12 mg of Bifidobacterium administered daily. The primary endpoint was the change in total Gastrointestinal Symptom Rating Scale (GSRS) score (range: 1–7) in the full analysis set (BBG9‐1: n = 43; control: n = 51). Results BBG9‐1 intake significantly improved the GSRS total score (from 2.22 ± 0.67 to 1.83 ± 0.62) compared with control (from 2.08 ± 0.67 to 2.06 ± 0.63; between‐group difference, −0.34 [95% CI: −0.55 to −0.14; p = 0.001]). Subgroup analyses indicated greater GSRS total score improvement in women, participants with constipation, aged ≥ 65 years, and BMI < 25 kg/m 2 . Among the GSRS subscales, BBG9‐1 showed a significantly greater mean reduction in constipation scores than control (−0.79 ± 1.38 vs. −0.13 ± 1.04; p = 0.013). Although the mean change in diarrhoea scores did not differ significantly (−0.42 ± 1.14 vs. −0.06 ± 1.08; p = 0.14), the follow‐up diarrhoea score was significantly lower with BBG9‐1 (2.04 ± 1.00 vs. 2.58 ± 1.44; p = 0.049). Through gut microbiota analysis, the relative abundance of genera Phocaeicola increased significantly in the BBG9‐1 group (from 15.98 ± 13.75 to 19.56% ± 14.79% vs. from 18.14 ± 14.17 to 18.21 ± 13.58, p = 0.042). Assessment of faecal short‐chain fatty acids (SCFAs) revealed no significant changes associated with BBG9‐1 administration. The incidence of adverse effects were similar between the groups. Conclusions BBG9‐1 administration significantly improved gastrointestinal symptoms in patients with T2DM. Trial Registration Japan Registry of Clinical Trials (jRCTs051220127)