Modifying Diet to Improve Gut Microbiome

Study Overview
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Brief Summary
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The investigators will conduct a 2-arm randomized controlled pilot, feasibility feeding study in which 28 participants will be randomized to receive either a calorie-restricted Dietary Approaches to Stop Hypertension (DASH) diet or a calorie-restricted standard American diet provided by the study for 4 weeks. Participants will be non-Hispanic black or white, generally healthy females (14 black, 14 white). The investigators will collect fecal samples at multiple time points before, during, and after the dietary intervention to analyze for changes in the gut microbiota and functional-level metabolic products. This work will be led by an interdisciplinary team including expertise in bio-behavioral science, microbiology, nutrition science, bioinformatics, and biostatistics all with cross-cutting expertise in health disparities, prevention research, nutrition, the gut microbiota, inflammation and other biomarkers. The rationale for the proposed research is that once the interactions between race, diet, and the gut microbiota are more fully understood, targeted diet modifications may provide new and innovative approaches for the prevention and treatment of obesity and obesity-related diseases.

Official Title
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Modifying Diet and the Gut Microbiota to Reduce Obesity and Health Disparities

Conditions
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Obesity

Intervention / Treatment
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* Behavioral: DASH diet
* Behavioral: standard American diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: female non-Hispanic, black or white age 19-65 years BMI >= 30 kg/m^2 able to visit Bionutrition Unit daily Exclusion Criteria: gastrointestinal (GI) conditions i.e., irritable bowel, diverticulitis, peptic ulcers, Crohn's, GI cancers, and adenatomous polyps antibiotic or probiotic use in the previous 90 days tobacco use heavy alcohol consumption major medical conditions (e.g., renal disease, diabetes, cancer)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: DASH diet<br>calorie-restricted DASH diet (25% fat; 57% carbohydrate; 18% protein; 34 g fiber | Behavioral: DASH diet<br>* brief description<br>|
| Active Comparator: standard American diet<br>calorie-restricted standard American diet (35% fat; 51% carbohydrate; %15 protein; 14 g fiber | Behavioral: standard American diet<br>* describe<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean Weight Change of Participants | Weight change as measured by a scale in kilograms at multiple time points will be calculated and averaged. | Baseline to day 28 | 
| Mean Weight Change of Participants | Weight change as measured by a scale in kilograms at multiple time points will be calculated and averaged. | Day 28 to Day 42 | 
| Mean Weight Change of Participants | Weight change as measured by a scale in kilograms at multiple time points will be calculated and averaged. | Baseline to day 42 | 
| Diet-specific changes in secondary bile acid | The investigators will calculate changes in cholic acid in milligrams. | Baseline to day 28 | 
| Diet-specific changes in secondary bile acid | The investigators will calculate changes in cholic acid in milligrams. | day 28 to day 42 | 
| Diet-specific changes in secondary bile acid | The investigators will calculate changes in cholic acid in milligrams. | baseline to day 42 | 
| Diet-specific changes in inflammatory marker | The investigators will calculate changes in c-reactive protein in mg/L. | baseline to day 28 | 
| Diet-specific changes in inflammatory marker | The investigators will calculate changes in c-reactive protein in mg/L. | day 28 to day 42 | 
| Diet-specific changes in inflammatory marker | The investigators will calculate changes in c-reactive protein in mg/L. | baseline to day 42 | 
| Diet-specific changes in short chain fatty acids | The investigators will calculate changes in acetic acid in mmol/L | baseline to day 28 | 
| Diet-specific changes in short chain fatty acids | The investigators will calculate changes in acetic acid in mmol/L | day 28 to day 42 | 
| Diet-specific changes in short chain fatty acids | The investigators will calculate changes in acetic acid in mmol/L | baseline to day 42 |