The Effects of Postbiotic Supplementation in Female Athletes

Female athletes are often overlooked in scientific research, including the understanding of their digestive system and its impact on overall health, training, and performance. The gastrointestinal (GI) system plays a critical role in supporting digestion, nutrient absorption, and acting as a protective barrier for the body. While there is some knowledge about the differences in GI structure and function between males and females at rest, there is a lack of understanding regarding how these differences manifest during exercise, especially among female athletes and at different phases of the menstrual cycle. It has been observed that female athletes commonly report a higher prevalence of GI symptoms compared to males, with many experiencing an increase during menstruation. These symptoms, including bloating, abdominal discomfort, and irregular bowel movements, can significantly disrupt an athlete's training and performance. Elite female athletes have acknowledged that GI symptoms associated with the menstrual cycle have led to altered or disrupted training routines. While these symptoms are commonly recognized to affect a large portion of the female population, few interventions have been studied to assist in managing this discomfort. Some clinicians may direct their patients to take pain-relieving medications without any thoughts on the consequences of chronic use. One potential strategy to reduce GI symptoms during endurance exercise is probiotic-postbiotic supplementation. Various probiotic supplements have been shown to effectively decrease diarrhoea, constipation stress, and intestinal permeability, as well as impact immunologic outcomes. Postbiotics differ from probiotics in that they are made from microorganisms that are not alive. They allow the modulation of the composition and function of the gut microbiota and enhance the intestinal barrier to prevent unwanted substances from entering the body proper. While these biotics can relieve lower GI symptoms in irritable bowel syndrome (IBS), there is less consensus regarding their efficacy in modulating exercise-associated GI symptoms. Previous research by Pugh et al., 2019 has demonstrated that four weeks of probiotic supplementation was able to reduce GI symptoms during a marathon race, however this work was predominantly conducted in males and did not take menstrual cycle in consideration. This is important given that symptoms are commonly higher in the early follicular phase when a female experiences their period. Therefore, the aim of this study is to assess the effects of postbiotic supplementation on GI symptomology in female athletes. The aim of this present study is to investigate the influence of postbiotic supplementation on menstrual cycle symptoms and exercise-associated GI symptoms in female endurance athletes while exercising compared to symptoms while taking a placebo.

NCT Number	NCT07580118
Lead Sponsor	Liverpool John Moores University Collaborators: dsm-firmenich Switzerland AG
Conditions	Gastrointestinal Symptoms, Menstrual Cycle
Enrollment	100 participants
Start Date	2026-05-05
Primary Completion	2026-07-30 (estimated)
Study Completion	2026-09-30 (estimated)
Updated on ClinicalTrials.gov	2026-06-02