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The Effect of Low or High Dietary Fiber Diet on Volatile Organic Compounds in Exhaled Breath of Healthy Individuals
Sponsor: Örebro University, Sweden
Summary
The aim of this crossover intervention study is to evaluate the volatile organic compounds (VOCs) present in participants at baseline and how these levels change after consuming either a low- or high-dietary fiber diet for three days. This study will involve adults, 18-65 years old, without any gastrointestinal diseases. The primary objectives are to characterize baseline VOC profiles, assess changes in these profiles after a short-term dietary fiber intervention, determine if specific VOC patterns correlate with dietary fiber intake, and identify the time points at which VOC levels peak. This information will help establish the optimal timing for breath sampling and potentially provide insight into how VOC patterns relate to dietary fiber consumption and degradation. The expected outcome is that a high-dietary fiber diet will produce a VOC profile enriched in metabolites associated with fiber fermentation compared to a low-dietary fiber diet, and that these VOCs will be consistent with those identified in vitro during fecal fermentation. Each participant will serve as an internal control, enabling within-subject comparisons of VOC levels at baseline and following the dietary fiber intervention. Participants will receive a whole-food product that is rich in dietary fiber and will consume either a low-fiber diet (10 g/day) or a high-fiber diet (40 g/day) for three days. On the first day of each intervention, participants will also ingest a pH capsule to monitor gastrointestinal pH continuously throughout the three days. After a three-week washout period, participants will cross over to the other intervention arm and undergo another round of gastrointestinal pH monitoring. In addition to the dietary intervention, participants will complete food and health questionnaires to assess habitual fiber intake and dietary habits. Fecal samples will be collected for in vitro fermentation to functionally profile the gut microbiota by assessing fecal VOCs, short-chain fatty acids (SCFA), and the microbial enzymatic activity and its pH-dependent modulation.
Official title: Characterization of Fiber-degrading Microbiota in Individuals Without Gastrointestinal Diseases
Key Details
Gender
All
Age Range
18 Years - 65 Years
Study Type
INTERVENTIONAL
Enrollment
20
Start Date
2026-05
Completion Date
2027-03
Last Updated
2026-05-26
Healthy Volunteers
Yes
Conditions
Interventions
Low, High Fiber Diet
Dietary Intervention: Low Fiber Diet Whole food dietary fiber product, 10g of dietary fiber consumed per day for 3 days Dietary Intervention: High Fiber Diet Whole food dietary fiber product, 40g of dietary fiber consumed per day for 3 days
High, Low Fiber Diet
Dietary Intervention: High Fiber Diet Whole food dietary fiber product, 40g of dietary fiber consumed per day for 3 days Dietary Intervention: Low Fiber Diet Whole food dietary fiber product, 10g of dietary fiber consumed per day for 3 days