The effects of probiotics, prebiotics, and synbiotics on polycystic ovarian syndrome Original paper

What was reviewed?

This overview synthesized evidence from eight systematic reviews and meta-analyses investigating the effects of probiotics, prebiotics, and synbiotics on the management of polycystic ovarian syndrome (PCOS). The reviews collectively evaluated randomized controlled trials (RCTs) focusing on metabolic, hormonal, and inflammatory markers to clarify how microbiota-modulating interventions influence PCOS-related outcomes. The analysis spanned data from over 4,000 women with PCOS and assessed diverse probiotic strains, prebiotic compounds (like inulin and fructooligosaccharides), and their combinations (synbiotics), typically over 8–12 week periods.

Who was reviewed?

The population under review consisted of women with clinically diagnosed PCOS from multiple RCTs conducted predominantly in Iran and China. The trials included in the systematic reviews examined interventions using specific bacterial strains and dosages. Outcomes measured included anthropometrics (BMI, weight), glycemic indices (fasting glucose, insulin, HOMA-IR), lipid profiles, inflammatory biomarkers (CRP, hsCRP), oxidative stress markers (TAC, MDA), and hormone levels (testosterone, SHBG).

What were the most important findings?

The compiled reviews demonstrated that probiotic supplementation led to modest yet statistically significant reductions in fasting plasma glucose, fasting insulin, HOMA-IR, total cholesterol, triglycerides, VLDL-C, and BMI in women with PCOS. Some reviews noted increased levels of SHBG and improved insulin sensitivity indices such as QUICKI.

The microbial associations of clinical relevance include a restoration of beneficial bacteria often depleted in PCOS, such as Faecalibacterium prausnitzii, Bifidobacterium spp., and Lactobacillus spp.—species known for producing short-chain fatty acids (SCFAs) like butyrate. SCFAs modulate insulin sensitivity, reduce gut permeability, and regulate inflammatory responses. Furthermore, synbiotics had mixed effects; while some reviews reported improvements in glucose and lipid profiles, the benefits were generally less consistent or weaker than probiotics alone.

What are the implications of this review?

This review reinforces the emerging role of the gut microbiota in PCOS pathophysiology and highlights the therapeutic potential of microbiota-targeted interventions. Probiotics demonstrated the most consistent benefits across glycemic, inflammatory, and hormonal parameters. These findings support the integration of microbiome-based strategies, such as targeted probiotic supplementation, into clinical practice for PCOS management. Clinicians should be aware that although results are promising, there remains high heterogeneity among studies in terms of strains used, dosages, and intervention durations. Larger, standardized clinical trials are necessary to define optimal regimens. Still, this growing body of evidence supports a microbiome-informed approach to PCOS care, particularly for improving insulin sensitivity, lowering inflammation, and potentially reducing androgen excess.