The Effect of Drinking-Water pH on the Human Gut Microbiota

Study Overview
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Brief Summary
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This study evaluates the effect of alkaline (pH=9) versus neutral (pH=9) drinking-water on the gut microbiota of healthy male volunteers.

Conditions
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Healthy Participants

Intervention / Treatment
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* Other: Alkaline drinking-water
* Other: Neutral drinking-water


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male Non-smoker Age 18 - 35 years Weight stabile for at least 2 months BMI between 20.0 - 27.0 kg/m^2 Exclusion Criteria: Habitual consumption of caloric or artificially sweetened beverages in excess of 1L/week Habitual average consumption of alcohol in excess of 7 drinks/week Antibiotic treatment within two months of inclusion Chronic or acute illness Previous abdominal surgery

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Alkaline water<br>Two liters (minimum) daily of alkaline drinking-water (pH=9) for 14 days | Other: Alkaline drinking-water<br> <br> |
| Active Comparator: Neutral Water<br>Two liters (minimum) daily of neutral drinking-water (pH=7) for 14 days | Other: Neutral drinking-water<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Shannon's alpha diversity index | Diversity of the gut microbial community | Intervention day 14 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Simpsons' reciprocal diversity index | Diversity of the gut microbial community | Intervention day 14 | 
| Observed richness | Observed number of operational taxonomic units | Intervention day 14 | 
| Estimated richness | Number of operational taxonomic units estimated using the Chao1 method | Intervention day 14 | 
| Unweighted UniFrac | Inter-individual diversity of the gut microbial community assessed using principal coordinate ordination of unweighted UniFrac distances | Intervention day 14 | 
| Weighted UniFrac | Inter-individual diversity of the gut microbial community assessed using principal coordinate ordination of weighted UniFrac distances | Intervention day 14 | 
| Bray-Curtis | Inter-individual diversity of the gut microbial community assessed using principal coordinate ordination of Bray-Curtis distances | Intervention day 14 | 
| Operational taxonomic unit | Relative abundance of individual operational taxonomic units | Intervention day 14 | 
| Bacterial genera | Relative abundance of operational taxonomic units aggregated at genus level | Intervention day 14 | 
| Plasma glucose; global | Global test of intervention effect on plasma glucose concentration during an oral glucose tolerance test | Intervention day 14 | 
| Serum insulin; global | Global test of intervention effect on serum insulin concentration during an oral glucose tolerance test | Intervention day 14 | 
| Serum insulin; individual timepoints | Intervention effect on serum insulin concentration at individual timepoints druing an oral glucose tolerance test | Intervention day 14 | 
| Plasma glucose; individual timepoints | Intervention effect on plasma glucose concentration at individual timepoints druing an oral glucose tolerance test | Intervention day 14 | 
| High sensitivity C-reactive protein |  | Intervention day 14 |