Effects of probiotics, prebiotics, and synbiotics on polycystic ovary syndrome: a systematic review and meta-analysis

Systematic review and meta-analysis of 17 randomized controlled trials including 1049 women with PCOS, most diagnosed by Rotterdam criteria. Studies were conducted mainly in Iran, with two trials from China, and compared probiotic, prebiotic, or synbiotic supplementation against placebo.

This systematic review evaluated probiotic, prebiotic, and synbiotic supplementation in women with polycystic ovary syndrome. The included randomized trials used varied formulations and doses, with interventions lasting 8 weeks to 3 months or 12 weeks in most studies, compared with placebo.

Overall, probiotic, prebiotic, and synbiotic supplementation improved several metabolic markers in women with PCOS. Pooled results showed lower insulin resistance indices, including HOMA-IR, FPG, and FINS, with higher QUICKI, and improved lipid profiles, including lower TG, TC, LDL-c, and VLDL-c. The interventions did not significantly change anthropometric indices or CRP. Subgroup analyses suggested probiotics were more effective for insulin resistance and prebiotics for lipid outcomes, with larger effects seen at longer durations and higher probiotic doses.

The meta-analysis was limited by substantial heterogeneity across trials, varied supplement formulations and doses, and mostly short intervention durations. Generalizability was limited because most studies were conducted in Iranian populations, and the authors called for larger, better-designed randomized trials.