The purpose of this dietary intervention is to study the effects of several dietary fibers on the gut microbiota at the personal level. Hypothesis 1: Intake of specific dietary fibers improves the blood lipid profile depending on the personal microbiota of the participants. Hypothesis 2: detailed food intake analysis and continuous monitoring of gut microbiota enables to draw causative interrelationships between food components, bacteria of gut microbiome and health characteristics.
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 1. Complete preliminary study questionnaire 2. Complete orientation to the study and provide voluntary consent to join the study 3. Collection of coded intervention products, sampling supplies, and instructional materials 1-WEEK QUESTIONNAIRE AND LABORATORY VISIT 1\. 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 1. Record food intake and gastrointestinal symptoms for 7 days 2. Collect health data and provide a 3-day food frequency questionnaire 3. Provide a stool and blood sample at the laboratory BLOOD SAMPLE ANALYSES 1\. 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: 1. Baseline mapping (health questionnaire, 1 week food diary before sampling of blood and gut microbiota) 2. Dietary fiber 1, 3 weeks, analyses: health questionnaire, 1 week food diary before sampling of blood and gut microbiota 3. Wash-out period, 2 weeks, analyses: health questionnaire, 1 week food diary before sampling of blood and gut microbiota 4. 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.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
15
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Center of Food and Fermentation Technologies
Tallinn, Harju, Estonia
Evaluation of the intestinal microbiota
Fecal microbiota analysis based on the 16S ribosomal RNA (rRNA) sequencing pre- and post-dietary intervention.
Time frame: 150 days
Evaluation of food consumption data
All foods consumed were collected 1 week before the end of every study period using web-based program (tap.nutridata.ee)
Time frame: 150 days
Evaluation of blood lipid profile
Triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol after every intervention and wash-out in plasma (mmol/L).
Time frame: 150 days
Evaluation of blood glucose levels
Fasting glucose pre- and post-dietary intervention in plasma (mmol/L).
Time frame: 150
Evaluation of liver characteristics profile
Uric acid, aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), gamma-glutamyltransferase (GGT) after every intervention and wash-out in plasma (mmol/L).
Time frame: 150
Evaluation of the stool form
Stool form will be assessed using a validated 7-point scale called Bristol Stool Form Scale pre- and post-dietary intervention.
Time frame: 150 days
Evaluation of the defecation frequency
1. Evacuation frequency 7 days before every blood and microbiome sampling. 2. Evacuation frequency (number of bowel movements per week) pre- and post-dietary intervention.
Time frame: 150
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Evaluation of the gastrointestinal symptoms
Frequency and severity of the gastrointestinal symptoms (Constipation, Diarrhea, Bloating, Flatulence, Cramps, Stomach pain). Scale of frequency: Never, Less than 10 times a year, Once a month, Once a week, Every day. Scale of severity: I do not have any gastrointestinal symptoms, Mild (does not disturb), Moderate, Strong (disturbs considerably).
Time frame: 150