• Gut–Brain Axis and Premenstrual Syndrome: The Role of Microbiota and Nutrition in Psychological Symptom Regulation
  • Zahra Nasrollahi,1,*
    1. Kermanshah University of Medical Sciences, Faculty of Medicine


  • Introduction: Premenstrual Syndrome (PMS) is a highly prevalent condition, affecting up to 80% of women of reproductive age worldwide. While physical symptoms such as bloating and breast tenderness are common, psychological manifestations—irritability, anxiety, depression, and mood instability—are among the most distressing features that impair quality of life. Despite decades of research, the precise pathophysiology of PMS remains elusive. Hormonal fluctuations in the luteal phase of the menstrual cycle play a critical role, yet they do not fully explain the wide inter-individual variability observed. In recent years, attention has shifted toward the gut–brain axis, a bidirectional communication network linking intestinal microbiota, the immune system, neuroendocrine pathways, and the central nervous system. Dysbiosis, or imbalance in gut microbial composition, has been associated with mood disorders, sleep disturbance, and altered stress responses. Similarly, dietary factors influence microbiota composition and, consequently, neurotransmitter synthesis, including serotonin and gammaaminobutyric acid (GABA). Given that approximately 95% of the body’s serotonin is synthesized in thegut, exploring the relationship between nutrition, microbiota, and PMS is of growing scientific and clinical interest. The present review summarizes current evidence on the link between gut microbiota, nutrition, and psychological symptoms in PMS, highlighting both observational findings and interventional trials using probiotics and dietary modification.
  • Methods: A narrative review was conducted by searching PubMed, Scopus, and Web of Science databases for studies published between 2010 and 2025. Keywords included “premenstrual syndrome,” “PMS,” “gut microbiota,” “nutrition,” “diet,” “probiotics,” and “psychological symptoms.” Eligible studies included: 1.Observational studies evaluating gut microbial composition in women with PMS. 2.Interventional studies assessing dietary modification or probiotic supplementation. 3.Review articles focusing on gut–brain interactions in premenstrual disorders. In total, 28 studies were identified, of which 12 met inclusion criteria. These comprised 3 observational studies, 6 interventional trials, and 3 systematic or narrative reviews. Data on study design, population, interventions, and main outcomes were extracted and synthesized.
  • Results: Evidence from cross-sectional studies indicates that women with PMS exhibit distinct gut microbial signatures compared to healthy controls. Reduced microbial diversity and lower abundance of Lactobacillus and Bifidobacterium species have been consistently reported. These alterations are associated with heightened inflammatory markers and increased severity of psychological symptoms. Interventional studies provide preliminary but encouraging findings: Lactobacillus gasseri CP2305 supplementation significantly improved irritability, anxiety, and sleep quality in women with PMS (n=60, RCT, 8 weeks). Lactobacillus paragasseri OLL2809 intake over three menstrual cycles reduced mood swings and improved overall symptom scores in a double-blind trial (n=40). Nutritional interventions such as increased intake of omega-3 fatty acids, magnesium, and vitamin B6 demonstrated synergistic effects with probiotics in reducing psychological distress. High sugar and low-fiber diets were linked to greater symptom severity, likely due to their negative effects on microbial diversity and inflammatory responses. Mechanistic studies further support the role of microbial modulation: specific gut bacteria influence tryptophan metabolism and serotonergic pathways, thereby affecting mood regulation. Moreover, gut-derived short-chain fatty acids (SCFAs) have anti-inflammatory effects that may mitigate neuroinflammation associated with PMS. Despite these findings, results remain heterogeneous. Sample sizes are generally small, follow-up durations are short, and diagnostic criteria for PMS vary across studies, limiting comparability.
  • Conclusion: he emerging evidence suggests a significant role of the gut–brain axis in the pathophysiology of PMS, particularly in the regulation of psychological symptoms. Altered gut microbiota composition and poor dietary patterns may exacerbate PMS-related distress, while probiotic supplementation and targeted nutritional interventions show promise as non-pharmacological therapeutic strategies. However, the current literature remains limited by methodological variability and insufficient large-scale randomized controlled trials. Future research should aim to standardize PMS diagnostic criteria, employ metagenomic sequencing for precise microbial characterization, and evaluate long-term efficacy of combined nutritional and probiotic therapies. Understanding the interplay between microbiota, nutrition, and hormonal cycles has the potential not only to improve PMS management but also to shed light on broader applications of the gut–brain axis in women’s mental health.
  • Keywords: PMS, Gut–Brain Axis, Microbiota, Nutrition, Probiotics