High-Fiber Diet or Combined With Acarbose Alleviates Heterogeneous Phenotypes of Polycystic Ovary Syndrome by Regulating Gut Microbiota Original paper

What was studied?

This randomized controlled clinical trial investigated the effects of a high-fiber diet, alone or combined with the alpha-glucosidase inhibitor acarbose, on the clinical phenotypes of polycystic ovary syndrome (PCOS) through modulation of the gut microbiota. The study specifically aimed to determine how dietary fibers and delayed carbohydrate absorption impact hormonal, metabolic, and inflammatory markers, as well as gut microbiome composition, in women with PCOS.

Who was studied?

Twenty-five women diagnosed with PCOS according to the Rotterdam criteria were recruited and randomly assigned into two groups. Fourteen participants received a whole-grain, traditional Chinese medicinal, and prebiotic-rich high-fiber diet (WTP diet), while eleven received the same diet combined with acarbose. The intervention lasted 12 weeks. All participants were treatment-naïve and not on hormone therapy, insulin sensitizers, or antibiotics for at least three months prior to enrollment. The study population spanned a reproductive age range (15–41 years), and measurements included hormonal, glycolipid, inflammatory, and microbiota parameters at weeks 0, 4, 8, and 12.

What were the most important findings?

Both interventions improved PCOS clinical phenotypes, but the combination of a high-fiber diet and acarbose yielded significantly better outcomes in lowering testosterone, LH/FSH ratio, fasting insulin, and HOMA-IR. Moreover, participants in the combination group experienced a more pronounced reduction in ovarian volume, hirsutism score, and immature follicles. These improvements paralleled significant shifts in the gut microbiota.

Gut microbiota analysis revealed enrichment of beneficial taxa, including Bifidobacterium and Lactobacillus, which were negatively associated with PCOS-related markers such as testosterone, LH/FSH ratio, fasting insulin, leptin, and a-AGP, while positively correlated with anti-inflammatory markers like adiponectin and spexin. In contrast, CAGs rich in Bacteroides vulgatus, Alistipes, Bilophila, Lachnospira, and Roseburia were significantly inhibited, particularly in the combination group, and positively associated with hyperandrogenism, insulin resistance, and inflammatory markers. These microbial changes suggest that the beneficial effects were mediated through enhanced SCFA production, gut-brain peptide modulation, and reduced LPS-related inflammation.

What are the greatest implications of this study?

This study provides compelling clinical evidence that gut microbiota-targeted nutritional therapy, particularly high-fiber intake enhanced with acarbose, can modulate endocrine and metabolic disturbances in PCOS. By enriching SCFA-producing probiotics like Bifidobacterium and Lactobacillus, and suppressing pro-inflammatory taxa such as Bacteroides vulgatus and Alistipes, the intervention directly impacted core pathogenic mechanisms: hyperandrogenism and insulin resistance. Additionally, changes in gut–brain peptides like leptin, spexin, and orexin highlight a robust gut-brain axis involvement in PCOS pathophysiology. For clinicians, this trial supports incorporating microbiome-informed dietary strategies, including the use of prebiotic-rich foods and agents like acarbose, into PCOS management. While limited by small sample size, the mechanistic depth, hormonal modulation, and microbial specificity make a strong case for larger multicenter trials to validate this therapeutic paradigm.