--- title: Does diet affect PMS differently depending on a woman's gut bacteria? description: In this small study, women who produced equol (a chemical made by gut bacteria from soy) showed no link between eating vegetables and worse PMS, while women w url: https://niyora.com/research/papers/urinary-equol-production-capacity-dietary-habits-and-premenstrual-symptom-2026/ --- - [Niyora](https://niyora.com/) - [Research](https://niyora.com/research/) - [Library](https://niyora.com/research/library/) - Does diet affect PMS differently depending on a woman's gut bacteria? Survey study, 2026 # Does diet affect PMS differently depending on a woman's gut bacteria? In this small study, women who produced equol (a chemical made by gut bacteria from soy) showed no link between eating vegetables and worse PMS, while women without equol showed a link. The study is too small and observational to know if changing diet helps. Early or limited evidence 41 Japanese women, ages 19-20 ## What they did Researchers measured equol in urine from 41 Japanese women aged 19-20, asked them about their diet with focus on soy and fiber foods, and measured PMS symptoms using a standardized questionnaire. ## What they found Only 12% produced equol. Equol producers ate more pumpkin, soybean sprouts, and green tea. Among non-producers, higher intake of vegetables and fiber foods (broccoli, pickled radish, konjac, konjac jelly) was linked to worse PMS. This link was not seen in equol producers. ## What it means for you Equol production status may affect how diet relates to PMS and could be a useful marker. The study is very small and observational only. Larger studies are needed to test whether equol testing helps predict how diet affects PMS. 41 Women studied 12% Equol producers 19-20 Age range ## About the study Original title Urinary Equol Production Capacity, Dietary Habits, and Premenstrual Symptom Severity in Healthy Young Japanese Women Authors Kada-Kondo N, Kimura N, Isobe K et al. Journal Metabolites Year 2026 Study design Survey study Participants 41 What was tested Equol production status and dietary habits (observational) Open access Yes Read the paper [doi.org/10.3390/metabo16010055](https://doi.org/10.3390/metabo16010055) Original abstract Background/Objectives : Equol, a gut microbial metabolite of the soy isoflavone, daidzein, is associated with estrogenic activity and potential benefits for women's health. While equol production depends on individual gut microbial composition, its dietary and clinical correlates in young women remain incompletely characterized. This study explored the relationship between urinary equol production, dietary habits, and premenstrual symptom severity in healthy university-aged women. Methods : We conducted a cross-sectional study of 41 Japanese women, aged 19-20 years. Urinary equol was measured using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, following enzymatic hydrolysis. Participants were classified as either equol producers or non-producers, based on urinary concentration thresholds. Dietary intake was evaluated using a dietary questionnaire focused on soy products and dietary fiber sources. Premenstrual symptoms were assessed using a standardized Japanese questionnaire for premenstrual syndrome and premenstrual dysphoric disorder. Results : Twelve percent of participants were classified as equol producers. Compared with non-producers, equol producers reported higher consumption of pumpkin, soybean sprouts, and green tea. Among non-producers, higher consumption of certain vegetables and fiber-rich foods, including broccoli, pickled radish, konjac, and konjac jelly, was associated with greater premenstrual symptom severity, whereas such associations were not observed among equol producers. The analytical method demonstrated high sensitivity and reproducibility for urinary equol measurement. Conclusions : These findings suggest that equol production status may be associated with distinct dietary patterns and with differences in the relationship between food intake and premenstrual symptom severity in young women. Although the cross-sectional design and limited sample size preclude causal inference, these findings suggest that urinary equol is a promising candidate biomarker for future research on diet-related modulation of premenstrual symptoms. Reproduced under CC-BY. ## Topics [Premenstrual syndrome (PMS)](https://niyora.com/research/topics/condition-pms/)[Premenstrual dysphoric disorder (PMDD)](https://niyora.com/research/topics/condition-pmdd/)[Diet and nutrition](https://niyora.com/research/topics/treatment-diet/)[IBS and gut symptoms](https://niyora.com/research/topics/comorbidity-ibs-gi/)[Relationships and partners](https://niyora.com/research/topics/life-area-relationships/)[Adolescents and young people](https://niyora.com/research/topics/life-area-adolescents/) Research tells you what helps on average. Niyora helps on the day it hits. Calm down, see it another way, and decide what to say, with a PMS and PMDD app built by a doctor. ## Related studies Survey study, 2019 What lifestyle and sleep habits are linked to PMS in teenage girls? Cohort study, 2026 Are eating behaviors linked to how severe a woman's PMS symptoms are? Survey study, 2017 Is premenstrual syndrome linked to anxiety, digestive problems, and food choices? Cohort study, 2006 How should severe period pain in teenagers be treated? Survey study, 2026 What dietary, lifestyle, and psychological factors are associated with PMS in young women? Survey study, 2023 What factors make some women more likely to have PMS or PMDD? Ask AI about this page Copy prompt ChatGPT ↗ Claude ↗ Perplexity ↗ Google AI Mode ↗ Grok ↗