Dietary interventions and the gut microbiota: a systematic literature review of 80 controlled clinical trials.
Level 1 - systematic review of randomized trials
Systematic review of 80 controlled clinical trials
PubMed 41501909 · doi:10.1186/s12967-025-07428-9
What was done
Authors conducted a systematic review following PRISMA guidelines across PubMed, EMBASE, Cochrane CENTRAL, CINAHL, and Scopus to evaluate the effects of dietary interventions on gut microbiota and biological markers in healthy and clinical adult populations. Eligible studies were controlled trials reporting within-group changes from baseline in microbial taxonomy, diversity, or blood/faecal/urine biomarkers. Screening, data extraction, and risk-of-bias assessments were conducted by two independent reviewers.
What was found
Eighty controlled trials covering 13 distinct dietary interventions were identified. Diets induced within-group taxonomic shifts but were not consistently associated with changes in alpha or beta diversity. Mediterranean, Japanese, Korean, calorie-restricted, high-polyphenol, high-fibre, plant-based, low-fat, and low-protein diets were associated with increased abundance of short-chain fatty acid (SCFA)- or lactic acid-producing taxa, decreased opportunistic pathogens, and lower inflammatory markers. Western, animal-based, low-FODMAP, ketogenic, and gluten-free diets were associated with reduced SCFA-producing bacteria. Specific numeric effect sizes and statistical values were not reported in the abstract.
Why it matters
This review compiles controlled trial evidence showing distinct microbial shifts across diverse dietary patterns, identifying which dietary interventions reliably enrich beneficial SCFA producers versus those that deplete them.
Limits
The total number of human participants was not reported in the abstract. Synthesis relied on within-group changes rather than quantitative between-group meta-analysis, and the authors noted substantial methodological and reporting heterogeneity across included studies.
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