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| Name | Class |
|---|---|
| Wageningen University and Research | OTHER |
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The aim of this study is to understand how the gut microbiome influences how much dietary energy humans excrete via feces. This study is based on the hypothesis that levels of methane in exhaled breath represent two different gut microbiome community structures, and therefore influence fecal energy excretion differently. Moreover, this study is assessed in the context of two different diets, both isocaloric and equal in macronutrient composition, but differing in contents of fiber, resistant starch, and large particles; which are hypothesized to impact the gut microbiome differently.
The trial is a cross-over trial including two controlled isocaloric dietary interventions of three days duration. The two diets are isocaloric but with different contents of fiber, resistant starch, and food particle sizes. Each intervention is separated by a wash-out period of at least 10 days where participants adhere to their habitual diet. The trial includes a total of five visits (one screening visit and four regular visits).
Before the trial, participants undergo a screening period of 4 days. During the 4-day screening period, participants measure the levels of methane in their exhaled breath. Based on median breath methane levels, participants are allocated to one of the two arms: (HMP: high methane producers; LMP: low methane producers). Enrollment in the intervention trial will be conducted so there are similar numbers of participants in both arms.
At the beginning and at the end of each 3-day intervention period, participants consume a blue muffin, containing a royal blue dye that changes the stool color. The appearance of the color in stool following the first muffin will mark the beginning of the stool collection period, which will continue until the stool color change is no longer noticeable following consumption of the second muffin. Therefore, the duration of the stool collection period, which is estimated to be on average 3 days, will ultimately depend on the participants' passage time of food (i.e., intestinal transit time).
During the screening period, participants are asked to:
Before each intervention period, participants are asked to:
At the visits before each intervention period, the following samples are collected:
During the intervention periods, participants are asked to:
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| High-methane producers | Experimental | Individuals exhaling high levels of methane (median exhaled methane >= 5 ppm), as measured 3-times daily during the screening period. |
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| Low-methane producers | Experimental | Individuals exhaling low levels of methane (median exhaled methane < 5 ppm), as measured 3-times daily during the screening period. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Diet A group | Other | Diet high in fiber (> 40g/10MJ), high in resistant starch (> 10g/10MJ), and containing large food particles. Diet is provided for 3 full days, consists of three meals per day (breakfast, lunch, and dinner) and in-between meals, and covers 100% of the participants' energy requirements. |
| Measure | Description | Time Frame |
|---|---|---|
| Total fecal energy excretion (between high- and low-methane producers) | Differences in total fecal energy excretion, determined as total kilocalories excreted via feces, between low and high methane producers following intake of the two controlled, isocaloric diets. | During each stool collection period (following each 3-day intervention period) |
| Measure | Description | Time Frame |
|---|---|---|
| Total fecal energy excretion (between diet A and diet B) | Differences in total fecal energy excretion, determined as total kilocalories excreted via feces, between the two isocaloric diets (that differ in fiber, resistant starch, and particle size). | During each stool collection period (following each 3-day intervention period) |
| Measure | Description | Time Frame |
|---|---|---|
| Gut microbiome-derived metabolites (fecal samples) | Differences in gut microbiome-derived metabolites, such as short-chain fatty acids, bile acids, amino acid-derived metabolites, and other metabolites derived from microbial proteolytic and saccharolytic fermentation measured from fecal samples, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
Inclusion Criteria:
Exclusion Criteria:
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University of Copenhagen, Department of Nutrition, Exercise and Sports | Frederiksberg | Capital Region | 1958 | Denmark |
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Overall, there are two parallel arms - high- (HMP) and low- (LMP) methane producers, to which the participants are allocated in a ratio 1:1 after a 4-day screening period, where individual levels of methane in exhaled breath are measured multiple times.
In both arms, participants undergo two 3-days dietary interventions in a crossover design and separated by a +10-day washout period. Participants are randomized to receiving diet A first or diet B first. These two diets are isocaloric and equal in macronutrient composition, but differ on dietary fiber, resistant starch and food particle size.
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| Diet B group | Other | Diet low in fiber (< 10g/10MJ), low in resistant starch (< 3g/10MJ) and containing small food particles. Diet is provided for 3 full days, consists of three meals per day (breakfast, lunch, and dinner) and in-between meals, and covers 100% of the participants' energy requirements. |
|
| Fecal energy density |
Differences in fecal energy density, determined as fecal energy (kcal) relative to fecal weight, between high- and low-methane producers. |
| During each 3-day intervention period and its following stool collection period |
| Total fecal weight excreted | Differences in total fecal weight excreted, determined as dry weight (grams), between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Breath hydrogen and methane levels | Differences in breath methane and hydrogen concentration in exhaled breath, measured in parts per million (PPM), between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Whole-gut transit time | Differences in whole-gut transit time, determined by the passage time of muffins with blue dye, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Stool consistency | Differences in stool consistency, determined by Bristol Stool Scale, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Stool frequency | Differences in stool frequency, determined by defecation records registered by the participants, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Stool moisture | Differences in stool moisture, determined as fecal water content relative to fecal weight, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Fecal pH | Differences in fecal pH between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Fecal microbial load | Differences in fecal microbial load, determined as total microbial DNA reads in feces, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Fecal host DNA concentration | Differences in fecal host DNA concentration, determined as total human DNA reads in feces, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Fecal short-chain fatty acids | Differences in fecal short-chain fatty acid concentrations between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Gut microbiome composition (16S) | Differences in gut microbiome composition, determined by 16S amplicon sequencing of fecal DNA, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Gut microbiome composition and functions (shotgun sequencing) | Differences in gut microbiome taxonomic composition and functions, determined by shotgun sequencing of fecal DNA, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Gut microbiome-derived metabolites (urine samples) | Differences in gut microbiome-derived metabolites, such as short-chain fatty acids, bile acids, amino acid-derived metabolites, and other metabolites derived from microbial proteolytic and saccharolytic fermentation measured from urine samples, between high- and low-methane producers. | Before and during each 3-day intervention period |
| Gut microbiome-derived metabolites (blood samples) | Differences in gut microbiome-derived metabolites, such as short-chain fatty acids, bile acids, amino acid-derived metabolites, and other metabolites derived from microbial proteolytic and saccharolytic fermentation measured from blood samples, between high- and low-methane producers. | Right before each 3-day intervention period |
| Fecal metabolome (untargeted metabolomics) | Differences in the fecal metabolome, measured by LC-MS/MS untargeted metabolomics, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Urine metabolome (untargeted metabolomics) | Differences in the urine metabolome, measured by LC-MS/MS untargeted metabolomics, between high- and low-methane producers. | Before and during each 3-day intervention period |
| Blood metabolome (untargeted metabolomics) | Differences in the blood metabolome, measured by LC-MS/MS untargeted metabolomics, between high- and low-methane producers. | Right before each 3-day intervention period |
| Gastrointestinal symptoms | Differences in the gastrointestinal symptoms during the 3-day intervention period, measured using a visual analog scale, between high- and low-methane producers. | During each 3-day intervention period |
| Habitual diet records | Differences in habitual diet records registered by participants, between high- and low-methane producers. | Right before each 3-day intervention period |
| Habitual physical activity records | Differences in habitual physical activity records registered by participants, between high- and low-methane producers. | Baseline (before the first 3-day intervention period) |
| Body weight | Differences in body weight before intervention, between high- and low-methane producers. | Right before each 3-day intervention period |
| Body fat composition | Differences in body fat composition, measured through Dual-Energy X-ray Absorptiometry (DXA scan), between high- and low-methane producers. | Baseline (before the first 3-day intervention period) |
| Muscle composition | Differences in muscle composition, measured through Dual-Energy X-ray Absorptiometry (DXA scan), between high- and low-methane producers. | Baseline (before the first 3-day intervention period) |
| Bone composition | Differences in bone composition, measured through Dual-Energy X-ray Absorptiometry (DXA scan), between high- and low-methane producers. | Baseline (before the first 3-day intervention period) |
| Biomarkers of food intake (fecal samples) | Differences in biomarkers of food intake, measured by untargeted metabolomics and food DNA in fecal samples, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Biomarkers of food intake (urine samples) | Differences in biomarkers of food intake, measured by untargeted metabolomics in urine samples, between high- and low-methane producers. | Before and during each 3-day intervention period |
| Biomarkers of food intake (blood samples) | Differences in biomarkers of food intake, measured by untargeted metabolomics in blood samples, between high- and low-methane producers. | Right before each 3-day intervention period |
| Fecal particle size | Differences in fecal particle size between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Fecal carbon-to-nitrogen ratio | Differences in fecal carbon-to-nitrogen ratio between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Fecal redox potential | Differences in fecal redox potential, measured in millivolts (mV), between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Fecal biomarkers of inflammation: calprotectin | Differences in fecal biomarkers of inflammation, determined by fecal calprotectin, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Fecal biomarkers of intestinal permeability: zonulin | Differences in fecal biomarkers of intestinal permeability, determined by fecal zonulin, between high- and low-methane producers. | During each 3-day intervention period and its following stool collection period |
| Blood markers of glucose metabolism | Differences in blood markers of glucose metabolism, such as glucose, insulin and HbA1C, between high- and low-methane producers. | Right before each 3-day intervention period |
| Blood markers of lipid metabolism | Differences in blood markers of lipid metabolism, such as total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglycerides, between high- and low-methane producers. | Right before each 3-day intervention period |
| Blood markers of inflammation | Differences in blood markers of inflammation, such as CRP, IL-6, TNF-α, and other cytokines, between high- and low-methane producers. | Right before each 3-day intervention period |
| Blood markers of appetite | Differences in blood markers of appetite, such as glucagon, GLP-1, GLP-2, PYY, leptin, ghrelin, GIP, and CCK, between high- and low-methane producers. | Right before each 3-day intervention period |
| Blood markers of intestinal permeability: LBP | Differences in blood markers of intestinal permeability, such as lipopolysaccharide-binding protein (LBP), between high- and low-methane producers. | Right before each 3-day intervention period |