The Effects of Hydration on Gut Health and Thinking

Study Overview
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Brief Summary
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The central hypothesis is that improving hydration through increased water consumption will change the relative abundance of mucolytic bacteria found in the stool. Therefore the specific aims are 1) to quantify intervention effects on fecal microbiota relative abundance and plasma lipopolysaccharide binding protein, 2) observe the effects of the intervention on bowel frequency and signs/symptoms of gastrointestinal stress, and 3) to investigate relations between executive function and hydration status.

Detailed Description
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A single arm 3-week hydration intervention will be employed where participants increase their water consumption to 2 (F) or 2.5(M) liters per day which is approximately 70% of the AI for daily water consumption. Pre-test and follow-up measures of fecal microbiota, urinary hydration status, cognitive function, circulating markers, and dietary intake will be assessed at baseline and at 3-week follow up via laboratory visits.

Official Title
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Investigating the Effects of Increased Water Consumption on Markers of Gut Health, Microbiota, and Executive Function

Conditions
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Dehydration, Cognitive Change, Gastrointestinal Microbiota

Intervention / Treatment
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* Dietary Supplement: Water Intake


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 19-50 years of age 18.5-34.49 kg/m2 24-hour UOsm above 500 mOsm/kg No antibiotic use over the past 3 months Absence of metabolic diseases and use of diuretics Agree to maintain typical diet intake (e.g., dietary fiber) patterns during intervention Avoid consuming prebiotic and probiotic supplements during study participation Not pregnant Agree to follow the study protocol Exclusion Criteria: <19 or >50 years of age <18.5 or >34.49 kg/m2 24-hour UOsm <500 mOsm/kg Antibiotic use over the past 3 months Metabolic diseases and use of diuretics Not agree to maintain typical diet intake (e.g., dietary fiber) patterns for the duration of the intervention Not agree with avoiding consuming prebiotic and probiotic supplements during study participation Pregnant Not agree to follow study protocol

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

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: Prevention
Intervention Model: Single Group Assignment
Interventional Model Description: Single arm hydration water intake intervention with a baseline urine concentration threshold for eligibility
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Water Intake<br>3-week intervention period during which articipants will be asked to increase their daily plain water consumption to at least 2.5 L/d of water for males and 2L/d for females. | Dietary Supplement: Water Intake<br>* Participants will increase plain water consumption to at least 70% of the daily adequate intake for Americans depending on their sex.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fecal microbiota relative abundance | changes in the relative abundance of fecal microbiota | 3 weeks (baseline vs. follow-up) | 
| Plasma lipopolysaccharide (LPS) | changes in circulating LPS | 3 weeks (baseline vs. follow-up) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Copeptin | changes in plasma copeptin concentration | 3 weeks (baseline vs. follow-up) | 
| 24hr Urine Osmolality | changes in osmolality (mOsmol/kg) of urine samples | 3 weeks (baseline vs. follow-up) | 
| Attentional accuracy | Accuracy (%) on a computerized flanker task | 3 weeks (baseline vs. follow-up) | 
| Attentional Reaction Time | Reaction time (ms) on a computerized flanker task | 3 weeks (baseline vs. follow-up) | 
| Attentional processing speed | P3 event related potential latency (ms) using a computerized flanker task | 3 weeks (baseline vs. follow-up) | 
| 24hr Urine Specific Gravity | changes in specific gravity (USG) of urine samples | 3 weeks (baseline vs. follow-up) |