Yeast Mannans and Stool Frequency
Efficacy of Yeast Mannan Supplementation on Increasing Stool Frequency in Generally Healthy Adults: A Randomized Controlled Trial
University of Florida
70 participants
Jul 17, 2025
INTERVENTIONAL
Conditions
Summary
Findings from an open-label pilot study of 20 adults suggested that supplementation with 15 g/day of yeast mannans was highly tolerable and demonstrated specific modulation of the microbiota and increased stool frequency in a subset of subjects reporting ≤1 stool per day at baseline. The primary aim of this randomized, double-blind, controlled trial is to determine if yeast mannan supplementation at 12 g/day will increase stool frequency in generally healthy adults reporting ≤1 stool per day. Secondary aims will determine the effect of yeast mannans on intestinal transit time, gastrointestinal symptoms, fecal microbiota composition, and urinary and fecal metabolomics.
Eligibility
Inclusion Criteria5
- Adults who report a stool frequency of ≤ 1 per day.
- Able to provide written informed consent in English.
- Willingness to consume 1 supplement (12 g of yeast mannans or control) daily for 28 days.
- Willingness to maintain their usual diet and physical activity patterns throughout the study and refrain from the consumption of any yeast-based foods (e.g. Marmite or Vegemite) or yeast extract supplements.
- Willing to comply with study procedures, including stool and urine colle
Exclusion Criteria12
- Stool frequency of \< 3 per week
- Yeast allergy
- Vegan dietary pattern
- Self-reported kidney disease
- Elite athletes or long-distance runners
- Use of antibiotic drugs within 1 month of screening
- Current use of laxatives or antidiarrheal medications
- Use of other investigational products within 3 months of the screening
- Previously or currently being treated for intestinal diseases or conditions, including irritable bowel disease (i.e., IBS-D or IBS-mixed), Crohn's disease, ulcerative colitis, celiac disease, or gastrointestinal cancer.
- Previous gastrointestinal surgery (e.g., gastric bypass, fundoplication, bowel resection).
- Current cancer treatment.
- Currently pregnant.
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Interventions
Yeast cell wall fraction of manno-oligosaccharides and mannoproteins supplemented at 12 g/day.
A supplement containing yeast protein, yeast extract, and maltodextrin, provided at 12 g/day.
Locations(1)
View Full Details on ClinicalTrials.gov
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NCT06911177