The effectiveness of a plant-based milk with fermented brown rice on constipation symptoms via gut microbiota modulation: a double-blind randomized controlled trial

Clinical Snapshot

Key Findings

• P Value: P<0.05 for between-group differences in straining, bloating, and abdominal pain (secondary outcomes only)

• Effect Size: Not reported in abstract. Between-group differences in straining, bloating, and abdominal pain were statistically significant (P<0.05), but absolute effect sizes or mean differences are not provided.

• Primary Outcome: Complete spontaneous bowel movement (CSBM) rate — no statistically significant between-group difference observed. Both groups showed increases in CSBM over time.

• Nnt Or Sensitivity: NNT not calculable from available data. Machine learning models identified gut microbiota features predicting intervention responders, but model performance metrics (AUC, sensitivity, specificity) are not reported in the abstract.

• Confidence Interval: Not reported

Clinical Application

The intervention (500 mL/day of a commercially produced plant-based fermented brown rice milk for 3 weeks) is practically feasible as a dietary supplement. However, the product used is proprietary (Feihe Dairy), and equivalent products may not be available in all markets. Adherence to a daily liquid supplement for 3 weeks is generally achievable in motivated patients. Functional constipation is prevalent in Australia, affecting approximately 20–25% of the population, with significant healthcare burden. Current RACGP and Gastroenterological Society of Australia (GESA) guidelines recommend dietary fibre augmentation, adequate hydration, and physical activity as first-line management, with osmotic laxatives (e.g., macrogol, lactulose — PBS-listed) for pharmacological escalation. The intervention product is not TGA-registered or PBS-listed in Australia. Fermented foods and plant-based dietary approaches align with emerging evidence on gut microbiota modulation, but this single trial with a negative primary outcome and industry sponsorship is insufficient to support a change in Australian clinical practice. Clinicians should note that comparable dietary fibre and fermented food sources (e.g., kefir, yoghurt, high-fibre cereals) are widely available in Australia and supported by broader evidence bases. Adults with functional constipation, particularly those seeking dietary or non-pharmacological management strategies. The study population was exclusively Chinese adults, which may limit direct applicability to other populations with differing baseline dietary patterns and gut microbiota compositions.

Abstract

PURPOSE: To evaluate the effects of a plant-based milk with fermented brown rice on constipation symptoms in patients with functional constipation and to identify post-intervention gut microbial alterations that may underlie potential mechanisms. METHODS: This is a randomized controlled trial among 100 participants with functional constipation. Participants were randomly assigned to the intervention group (plant-based milk with fermented brown rice, 2 bottles/day, 500 ml in total), or the control group (an isocaloric plant protein milk, equivalent dose) for 3 weeks. The primary outcome is complete spontaneous bowel movement (CSBM) rate, while secondary outcomes include score of individual symptoms assessment of constipation, bowel movement frequency (BMF), and gut microbial changes (metagenomics). RESULTS: A total of 99 participants completed the intervention. CSBM and BMF increased, and GSRS scores decreased over time in both groups, with no significant between-group differences. The plant-based milk with fermented brown rice relieved constipation symptoms more than the control group did, with significant between-group differences in straining, bloating and abdominal pain (all P < 0.05). The intervention group showed increases in 8 species, including three beneficial species in the genus Blautia, associated with relief of abdominal pain after the intervention. Meanwhile, machine learning models identified gut microbiota features predicting intervention responders. CONCLUSION: Our study did not find between-group difference in CSBM, while the plant-based milk with fermented brown rice showed greater effectiveness in relieving constipation symptoms and optimizing gut microbiota. Functional species benefiting intestinal health in response to the intervention were also identified. CLINICAL TRIAL REGISTRY: This study has been registered in the Chinese Clinical Trial Registry (https://www.chictr.org.cn/, ChiCTR2400088688).

References

1. 1.Tang, A., Cao, Q., Wang, M., Li, W., Xu, H., Wang, Y., Niu, H., Wang, H., Ma, G., Jia, K., Feng, X., He, C., He, J., Alballa, M. M., Liao, X., Tian, T., Qin, B., Yang, N., Wei, J., Sun, J., Wang, Y., Cheng, Y., Wu, Q., Yang, J., Wang, Q., Wang, X., & Liu, X. (2026). The effectiveness of a plant-based milk with fermented brown rice on constipation symptoms via gut microbiota modulation: a double-blind randomized controlled trial. European Journal of Nutrition. https://doi.org/10.5056/jnm21202