Role of Acupuncture on Gut Microbiome Modulation: A Systematic Review of Randomized Controlled Trials

Abstract

Importance: The gut microbiome, composed of nonpathogenic bacteria, protozoa, and viruses, plays a critical role in human health through various regulatory mechanisms. Dysbiosis has been linked to multiple diseases. Acupuncture, a widely practiced complementary therapy, has been explored for its effects on microbial balance, but systematic reviews in this area remain limited. Objective: This systematic review aims to report acupuncture's role in gut microbiome modulation. Evidence Reviews: A systematic search of PubMed/Medline and Cochrane databases was conducted up to January 30, 2024, using terms including “acupuncture,” “gut,” “intestinal flora,” and “electroacupuncture.” Of 383 articles identified, five randomized controlled trials (RCTs) met inclusion criteria, focusing on bacterial taxonomic changes measured by 16S rRNA sequencing (16S ribosomal ribonucleic acid). Findings: Five RCTs (n = 457) investigated acupuncture's effects on gut microbiota in patients with Crohn's disease (n = 96), functional constipation (n = 108), antipsychotic-related constipation (n = 133), Parkinson's disease (n = 30), and knee osteoarthritis (n = 90), along with healthy individuals (n = 88). Across studies, acupuncture was associated with improved microbial diversity and increased beneficial bacterial abundance. These changes may involve modulation of the gut–brain axis, vagus nerve activation, and anti-inflammatory neuroendocrine pathways. No meta-analysis was performed due to heterogeneity in interventions and outcome measures. Conclusion and Relevance: This review provides an overview of current evidence, highlighting acupuncture's potential to modulate gut microbiota composition. Despite promising findings, the limited number of trials, population diversity, and small sample sizes restrict generalizability. Future research is required to understand the explicit mechanisms and identify acupuncture-specific bacteria in the intestine.