DASH INtervention to INvestigate the Gut

Study Overview
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Brief Summary
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The study investigators will recruit a generally healthy sample of 112 black and white adults from Birmingham, AL to participate in a 28-day randomized, controlled feeding study. Participants will be randomized to receive either the DASH diet or a standard American diet. All meals will be provided by the study. Fecal samples will be collected at multiple time points before, during, and after the dietary intervention and will be analyzed using PCR to amplify the V4 region of the 16S rRNA gene and to sequence bases using the MiSeq platform. Sequenced data will then be analyzed using QIIME. The investigators hypothesize that participants receiving the DASH diet will have a greater increase in alpha diversity and greater changes in abundances of CRC-associated microbes than participants receiving the standard American diet. The investigators will also evaluate functional-level markers including bile acid and short chain fatty acid (SCFA) production and inflammatory markers. If the investigator's hypothesis is supported, they expect to see reduced production of secondary bile acids (e.g., deoxycholic acid), greater SCFA production (e.g, butyrate), and reduction in gut and systemic inflammation (e.g, calprotectin, IL-6) among participants receiving the DASH diet compared to the standard American diet. The investigator's findings will provide preliminary evidence for the DASH diet as an approach for cultivating a healthier gut microbiota across racially diverse populations. These findings can impact clinical, translational, and population-level approaches for modification of the gut microbiota to reduce risk of chronic diseases like CRC.

Official Title
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Determining the structural-and Functional-level Effects of Diet-specific Interventions on the Gut-microbiota of a Diverse Sample of Southern United States Adults

Conditions
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Microbiota, Cancer

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: black or white race non-Hispanic ethnicity age 19-65 years able to travel to the UAB Bionutrition Unit daily to retrieve meals 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 smoking/tobacco use heavy alcohol consumption major medical conditions (e.g., renal disease, diabetes, cancer

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 65 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
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


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>* Participant will receive foods following the DASH dietary pattern for 28 days.<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>* Participants will receive foods following the standard American diet for 28 days.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean change in alpha diversity | The investigators will assess the difference in alpha diversity determined by analyzing fecal samples. | baseline - day 28 | 
| Mean change in alpha diversity | The investigators will assess the difference in alpha diversity determined by analyzing fecal samples. | day 28 - day 42 | 
| Diet specific changes in secondary bile acids | The investigators will calculate changes in cholic acid in milligrams | baseline - day 28 | 
| Diet specific changes in secondary bile acids | The investigators will calculate changes in cholic acid in milligrams | day 28 - day 42 | 
| Diet-specific changes in inflammatory marker | The investigators will calculate changes in interleukin-6 in pg/L | baseline - day 28 | 
| Diet-specific changes in inflammatory marker | The investigators will calculate changes in interleukin-6 in pg/L | day 28 - day 42 |