Prebiotic Inulin for Late-Reproductive Individuals

Overview

This study aims to evaluate the effects of 2 weeks of inulin supplementation in perimenopausal women with overweight or obesity. The primary questions this study seeks to answer are: 1. Does 2 weeks of inulin supplementation alter the gut and vaginal estrobolome compared with placebo? 2. Does 2 weeks of inulin supplementation affect cardiovascular health compared with placebo? 3. Does 2 weeks of inulin supplementation affect skeletal muscle health compared with placebo? Researchers will compare inulin with a placebo (a similar-looking supplement that does not contain inulin) to determine whether inulin influences gut and vaginal microbial function, cardiovascular health, and skeletal muscle health during the perimenopausal transition. Participants will: * Take either inulin or a placebo for 2 weeks, followed by a 2- to 4-week washout period, and then switch to the other supplement for an additional 2 weeks. * Attend 8 study visits over approximately 12 to 16 weeks for assessments and sample collection. * Complete weekly phone calls to monitor symptoms, supplement adherence, and dietary intake. * Wear a Fitbit device throughout the study to monitor physical activity.

This proposal presents a proof-of-concept study of the Prebiotic Inulin for Late Reproductive Individuals (PILI) intervention, a prebiotic fiber supplementation among women with perimenopause and overweight or obesity. More specifically, the PILI intervention integrates multi-omics, physiological, and cardiometabolic assessments to examine the effects of inulin supplementation on overall health during the menopausal transition. Outcomes include changes in the gut and vaginal microbiome and their functional activity, gut-derived metabolites, vascular health, metabolic flexibility, skeletal muscle oxidative capacity, body composition, physical activity, sleep, dietary intake, and other cardiometabolic health markers. The target age range for this intervention is 40-55 years, reflecting the perimenopausal stage of life. Participants must also have overweight or obesity. Participants will be randomly assigned to receive both the study intervention, inulin, and placebo, in a blind crossover design. Each participant will complete two intervention periods, separated by a washout period, allowing every participant to serve as her own control. Throughout the study, participants will consume the assigned supplement daily and attend scheduled in-person research visits before and after each intervention period. At these visits, the research team will collect biological samples, including blood, stool, and vaginal swabs, and perform a comprehensive series of clinical assessments. These assessments include body composition, vascular health, metabolic flexibility, skeletal muscle oxidative capacity using near-infrared spectroscopy, physical function, and cardiometabolic testing. Participants will also complete questionnaires related to dietary intake, physical activity, sleep, menopausal symptoms, and quality of life, while wearing a Fitbit device to objectively monitor physical activity and sleep throughout the study. The PILI study team will evaluate the feasibility of the intervention by assessing recruitment, retention, adherence to supplement consumption and study procedures, participant acceptability and tolerability, and completion of biological sample collection and clinical assessments. Preliminary changes in microbiome composition and function, microbial metabolites, and cardiometabolic health outcomes will also be evaluated to generate data that will inform the design of a future larger clinical trial. This research has the potential to advance understanding of how prebiotic supplementation influences the gut-muscle-metabolism axis during the menopausal transition and to identify a safe, low-cost nutritional strategy to improve cardiometabolic health among perimenopausal women.