Introduction: Insomnia is the most common sleep disorder in women. Many metabolic processes are involved in sleep regulation and depend on nutritional status, suggesting a link between diet and sleep1. Over the past decade, there has been increased interest in the analysis of ellagitannins—a group of polyphenols whose metabolites involve ellagic acid (EA) and urolithins (Uros). Uros are microbial-derived metabolites with high bioavailability, blood–brain barrier permeability, and documented antioxidant, anti-inflammatory, and neuroprotective properties2. However, Uros have not yet been analysed in the context of insomnia. This preliminary study will aim to evaluate the associations between urine metabolites of ellagitannins and insomnia occurrence among peri- and postmenopausal women.
Methods: This preliminary cross-sectional study involved 80 women aged 50–70, including 38 women with insomnia. Due to the direct impact on insomnia, the exclusion criteria for the study included neurological and psychiatric diseases. The occurrence of insomnia was assessed using the five-point WHIIRS scale (Women's Health Initiative Insomnia Rating Scale)3. The profile of ellagitannins metabolites in urine was analysed using the LC-MS technique.
Results: Three ellagitannin metabolites were identified in all urine samples (mean concentration): EA (12.6 nM), Uros C (2.8 nM), and Uros D (7.9 nM). Women without insomnia had slightly but significantly higher Uros C concentrations compared to women with insomnia (3.0 vs. 2.5 nM; p=0.0470). Uros A (1.3 nM) and B (1.0 nM) were identified in 80% and 14% women without insomnia and 74% and 8% women with insomnia, respectively.
Conclusions: The obtained findings provide promising preliminary data to design prospective studies involving diet and microbiome analyses to confirm the inverse association between Uros C concentration and insomnia occurrence and explain the mechanisms underlying them.
Research funding: This research was funded by the National Science Centre, Poland, grant number: 2024/08/X/NZ9/00854.
References: 1Binks et al., Nutrients 2020; 2Zhao et al. Mediators Inflamm. 2020; 3Hery et al. Sleep Health. 2020.
