Dietary Fiber and Gut Microbiome Study

The study design is a cross-over, pre-post intervention trial. All participants are enrolled into all study periods. Study consists of baseline period, four periods of dietary fiber intervention and four periods of wash-outs.

The main goal of this study was to elucidate the patterns between individual dietary fibers and gut microbiota at the personal level. Each person has a unique (individual) intestinal microbiological profile that changes according to lifestyle (diet, environment, physical activity), age and health status. With next generation sequencing methods to map microbial communities and detailed nutritional analysis including blood tests, it is possible to identify the specific effects of specific fiber on a selected (individual) microbiota. TFTAK researchers have long-term experience in microbiota analysis as well as diet design and nutrition analysis, which can be successfully applied in this project.

PRELIMINARY STUDY EVALUATION AND TESTING

• Complete preliminary study questionnaire
• Complete orientation to the study and provide voluntary consent to join the study
• Collection of coded intervention products, sampling supplies, and instructional materials

1-WEEK QUESTIONNAIRE AND LABORATORY VISIT

• Record food intake and gastrointestinal function for 7 days 2. Collect health data and provide a 7-day food diary using web-based program Nutridata (tap.nutridata.ee) 3. Provide a stool and blood sample at the laboratory 3-WEEK QUESTIONNAIRE AND

LABORATORY VISITS

• Record food intake and gastrointestinal symptoms for 7 days
• Collect health data and provide a 3-day food frequency questionnaire
• Provide a stool and blood sample at the laboratory BLOOD SAMPLE

ANALYSES

• Provide the blood sample at the laboratory in the morning in an overnight fasted state.

DIETARY INTERVENTION

Study consists of baseline period, four periods of dietary fiber intervention and four periods of wash-outs:

• Baseline mapping (health questionnaire, 1 week food diary before sampling of blood and gut microbiota)
• Dietary fiber 1, 3 weeks, analyses: health questionnaire, 1 week food diary before sampling of blood and gut microbiota
• Wash-out period, 2 weeks, analyses: health questionnaire, 1 week food diary before sampling of blood and gut microbiota
• Repeating 3 times periods of 2 and 3. In each dietary fiber period 15 g/day of oat fiber, rye fiber, mix I and mix II of dietary fibers are used as test compounds. Dietary fiber mix I and mix II are inulin, beta-glucan, polydextrose, citrus pectin and psyllium, and beta-glucan, citrus pectin and psyllium, respectively.

Inclusion criteria

• Age 20-60

• Normal bowel function
• Omnivorous diet
• Ability to provide a signed written informed consent
• Willing to provide stool and blood specimens over the 22-week study period

Exclusion criteria

• Diagnosed history of chronic diseases including coronary heart disease, stroke, cancer, type 1 or 2 diabetes mellitus, inflammatory bowel disease, gastritis, autoimmune disease, or rheumatoid arthritis

• Medication: statins, blood pressure medications, antidepressants, other prescription medications
• History of bariatric operation, removal of the gallbladder.
• Food allergies, lactose intolerance
• Recent (previous 3 months) use of antibiotics
• Intake of highly dosed pre- or probiotics 2 weeks prior and during the study
• Current pregnancy or breastfeeding
• Volunteers showing previously unrecognized illness will also be excluded
• Individual unable to give informed consent