Characteristics of the Gut Microbiota in Japanese Patients with Premenstrual Syndrome Original paper

What was studied?

The focus keyphrase gut microbiota in Japanese women with PMS captures the heart of this original research study, which investigated how the gut microbiota differs in Japanese women experiencing premenstrual syndrome compared with healthy controls. Through 16S rRNA gene sequencing of stool samples, the researchers quantified bacterial diversity and genus-level composition to determine whether PMS is associated with a characteristic microbial signature. The analysis included alpha-diversity (within-sample diversity), beta-diversity (between-sample differences), and differential abundance testing. The authors emphasized microbial patterns that may contribute to PMS-related symptoms, particularly genera involved in carbohydrate metabolism. These findings help extend the growing recognition that the gut–brain–hormone axis influences women’s health.

Who was studied?

The study examined 24 Japanese women diagnosed with PMS and 144 Japanese women without PMS serving as healthy controls, all aged 24–49 years. Participants were drawn from two databases, with careful exclusion of individuals who were pregnant, nursing, using antibiotics within the previous week, non-Japanese, or lacking complete microbiome data. Stool samples were collected between February and November 2021, and participant diet and lifestyle data were recorded. Despite a small PMS group, the dataset allowed comparison across age brackets, although women in their 20s were underrepresented. The two groups differed significantly in age but not BMI, and dietary patterns differed in several categories.

Most important findings

The gut microbiota in Japanese women with PMS showed distinct features compared with controls. Alpha-diversity measured by the Simpson index was significantly higher in the PMS group, indicating a broader distribution of dominant taxa. Beta-diversity analysis, visualized through NMDS plots, demonstrated clear group separation, suggesting meaningful structural differences between communities. The genus-level comparison identified Collinsella, Bifidobacterium, and Blautia as significantly more abundant in the PMS group, with Collinsella enriched 4.5-fold (3.96% vs. 0.88%) and exhibiting the largest effect size across age groups (pages 5–6). These taxa are metabolically active carbohydrate-utilizing bacteria known to produce lactate and other metabolites that may influence blood glucose fluctuations and mood. The table below summarizes key genera that differed significantly.

Key implications

These results suggest that gut microbiota in Japanese women with PMS harbors characteristic microbial signatures, especially elevated Collinsella. Because Collinsella abundance is sensitive to diet—including low-fiber intake and animal-protein–rich patterns—nutritional strategies or targeted prebiotics may help mitigate PMS symptoms by moderating microbial metabolism. The findings also raise the possibility that blood glucose instability, influenced by lactate-producing genera, contributes to emotional and physical symptoms. Further research using metabolomics and functional pathway analyses is needed to clarify mechanistic roles and develop evidence-based microbiome-informed interventions for PMS.

Citation

Okuma K, Kono K, Otaka M, et al. Characteristics of the gut microbiota in Japanese patients with premenstrual syndrome. Int J Womens Health. 2022;14:1435-1445. doi:10.2147/IJWH.S377066