Systematic review and meta-analysis demonstrates improved bowel movement frequency and transit time in healthy adults, suggesting fermented foods support digestive health.
Key Points
To systematically review and meta-analyze available evidence evaluating the impact of fermented food consumption on gastrointestinal wellbeing in healthy adults.
Searched MEDLINE, Scopus, and Cochrane CENTRAL databases up to January 31, 2025, synthesizing 25 studies with 4,328 participants.
Conducted meta-analyses on 19 randomized controlled trials evaluating outcomes using mean differences (MD) or standardized mean differences (SMD), with certainty evaluated via GRADE.
Fermented food consumption significantly increased bowel movement frequency (MD 0.60, 95% CI 0.04 to 1.16, p = 0.04, I² = 74%) and improved stool consistency on the Bristol Stool Form Scale (MD 0.25, 95% CI 0.03 to 0.47, p = 0.03, I² = 72%).
Intervention significantly shortened intestinal transit time (MD −13.65, 95% CI −21.88 to −5.43, p = 0.001, I² = 95%) and alleviated overall gastrointestinal symptoms (SMD −0.60, 95% CI −1.05 to −0.15, p = 0.009, I² = 90%), though overall certainty of evidence was mostly low.