Effects of inulin on intestinal flora and metabolism-related indicators in obese polycystic ovary syndrome patients Original paper

What was studied?

The focus keyphrase inulin and PCOS gut microbiota anchors this study, which examined how three months of dietary inulin supplementation affected gut microbiota composition, metabolic markers, inflammatory cytokines, and sex steroid hormones in obese women with polycystic ovary syndrome (PCOS). Drawing on stool sequencing and detailed plasma biomarker panels, the research tracked shifts across the gut microbiota–inflammation–hormone axis. According to the figures and microbial bar plots, the investigators compared pre- and post-inulin states alongside obese and non-obese controls, capturing changes in both microbial diversity and specific taxa such as Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, Lachnospira, Sutterella, Enterobacter, Lactobacillus, and Bifidobacterium.

Who was studied?

Fifty-five women from a reproductive medicine center in China participated, grouped into obese PCOS patients, obese controls, and non-obese controls. Thirteen obese PCOS participants who adhered strictly to the protocol completed the three-month inulin intervention, forming the core analysis group (FDA). All participants provided blood and stool samples before and after the intervention. Inclusion and exclusion criteria ensured that only PCOS cases defined by the Rotterdam criteria were included, and that no recent antibiotic, hormone, or probiotic exposures confounded gut microbiome results. The clinical and microbial comparisons across groups, described in Tables and PCA plots, allowed clear interpretation of obesity- and PCOS-specific microbiome patterns.

Most important findings

Inulin supplementation improved clinical, hormonal, inflammatory, and microbial parameters relevant to obese PCOS. BMI and waist-to-hip ratio trended downward, while sex steroid abnormalities—including elevated LH, LH/FSH ratio, testosterone, AMH, and estradiol—shifted toward healthier ranges. Pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, MCP-1) were significantly reduced after the intervention, as shown in the inflammatory scatterplots. Microbiome analysis revealed key taxonomic rebalancing. At the phylum level, inulin lowered the Firmicutes/Bacteroidetes (F/B) ratio and reduced Proteobacteria abundance, a phylum linked to dysbiosis and endotoxin (LPS) load. Actinobacteria and Fusobacteria increased following treatment. At the genus level, inulin increased beneficial Lachnospira and Bifidobacterium while decreasing Sutterella, Lactobacillus, Lactococcus, and Enterobacter—patterns displayed clearly in the LEfSe biomarker charts. Correlation heatmaps showed strong associations between microbial taxa, inflammatory markers, lipid profiles, and anthropometrics, indicating that microbial shifts accompanied measurable clinical improvements.

Key implications

This study demonstrates that dietary inulin can beneficially modulate the gut microbiota–inflammation–sex hormone axis in obese women with PCOS. The intervention improved dysbiosis, reduced pro-inflammatory cytokines, and incrementally corrected sex hormone imbalances, suggesting that microbiota-targeted therapy may complement existing PCOS treatments. The consistent reduction in Proteobacteria and restoration of Actinobacteria and Lachnospira highlight potential microbial signature candidates for monitoring therapeutic response. While the sample size is limited, the findings underscore the value of prebiotic interventions as accessible, low-risk adjuncts for managing metabolic-hormonal dysfunction in PCOS.

Citation

Li X, Jiang B, Gao T, et al. Effects of inulin on intestinal flora and metabolism-related indicators in obese polycystic ovary syndrome patients. European Journal of Medical Research. 2024;29:443. doi:10.1186/s40001-024-02034-9