Effectiveness of Probiotics, Prebiotics, and Synbiotics in Managing Insulin Resistance and Hormonal Imbalance in Women with Polycystic Ovary Syndrome (PCOS): A Systematic Review of Randomized Clinical Trials

Abstract

Background/Objectives: Polycystic ovary syndrome is a common endocrine disorder in women of reproductive age characterized by insulin resistance and hormonal imbalances. Recent research suggests that probiotics and synbiotics may improve these parameters by modulating the gut microbiota. This study systematically reviewed randomized clinical trials evaluating the impact of probiotic, prebiotic, and synbiotic supplementation on insulin resistance and hormonal parameters in women with PCOS. Methods: Exhaustive searches were conducted in PubMed, Cochrane CENTRAL, Scopus, Web of Science, and Embase, following PRISMA guidelines. Randomized trials assessing supplementation with probiotics, prebiotics, or synbiotics for at least 8 weeks in women diagnosed with PCOS according to the Rotterdam criteria were included. Data on participants, interventions, and outcomes related to insulin resistance and hormones were extracted. Results: Eleven studies from Iran involving overweight or obese women aged 15 to 48 were included. Probiotic and synbiotic supplementation showed significant improvements in insulin resistance (reductions in HOMA-IR, fasting glucose, and insulin), lipid profiles (decreased LDL and triglycerides; increased HDL), and hormonal balance (increased SHBG, decreased total testosterone). Synbiotics had more pronounced effects than probiotics or prebiotics alone. Adherence was high, and side effects were minimal. Conclusions: Despite promising results, limitations such as small sample sizes, homogeneous populations, and short intervention durations limit the generalization of the findings. Larger, longer, multicenter trials with diverse populations and standardized methodologies are needed to confirm the efficacy and safety of synbiotics in managing PCOS. Integrating these interventions could improve clinical management and quality of life for affected women, but additional evidence is required to support widespread use.

Keywords: gut microbiota; hormonal imbalance; insulin resistance; metabolic health; polycystic ovary syndrome (PCOS); probiotics; randomized controlled trials; synbiotics; systematic review; women’s health.

Figure 1

PRISMA flowchart. A Cohen’s kappa of 0.95 and 0.82 indicates a high level of agreement between reviewers, ensuring the validity of the results.

Figure 2

Clinical outcomes of prebiotic, probiotic, and synbiotic interventions in patients with PCOS. (A) Distribution of prebiotics, probiotics, and synbiotics used in interventions. (B) Changes in HOMA-IR, FBS, and insulin by intervention group. HOMA-IR (Homeostatic Model Assessment for Insulin Resistance) is marked in red. FBS (fasting blood sugar) is in orange. Insulin is in yellow. The bars reflect how each parameter changed based on the type of supplement used (probiotic, synbiotic, prebiotic, and control). (C) Relationship between duration of intervention and change in clinical parameters (Δ). Red dots represent changes in HOMA-IR. Green dots represent changes in FBS. Blue dots represent changes in insulin [38,39,40,45,46].

Figure 3

Cochrane risk-of-bias assessment for randomized studies of interventions in this systematic review. (A) Risk-of-bias summary: Review of the authors’ judgments about each risk-of-bias item for each included study. The symbol “+” indicates a low risk of bias, the symbol “?” indicates an unclear risk of bias. The colors used are green for low risk of bias, yellow for unclear risk of bias [37,38,39,40,45,46,48,49,50,51,52]. (B) Risk-of-bias graph: Review of the authors’ judgments about each risk-of-bias item presented as percentages across all included studies. Figure created by RevMan 5 (accessed on 24 August 2024).