Effects of Adding Raisins to the American Diet on Fecal Microbiota Composition

Raisins contain a significant amount of dietary fiber and polyphenolic compounds that represent an important substrate for microbiota fermentation which generates potentially beneficial end products, such as short-chain fatty acids. The mammalian gut contains a phylogenetically as well as functionally diverse microbiota that contributes to host physiology. To date, little is known about how increased raisin intake affects human gut microbiota composition.

This research study will assess the effects of adding raisins to the diet of healthy adults on the bacteria from feces of human subjects and resulting self-reported GI symptoms as well as markers of immune function. The hypothesis is that by adding raisins to the diet this will result in changes in gut microbiota. Furthermore, the changes in microbiota will largely be beneficial, as evaluated by an increase in butyrate producers and bacteria associated with anti-inflammatory properties.

Study Overview

• Status: Completed
• Conditions: Inflammation
• Intervention / Treatment: Other: Raisins

Detailed Description

The research study design is a 14 day international focus on increasing raising intake. Participants will be provided with a commercial raisin product for a 14 day period. Participants will consume 2 servings/day (84g of raisins). While participants will be told to substitute raisins for other diet ingredients, they will be free to choose what to substitute according to their preferences. Participants will keep daily food records and will be told that raisin consumption will be monitored in their fecal samples (qPCR). Fecal samples will be collected before the start (Day1), during (Day5-7) and at the end (Day 12-14) of the intervention using a stool collection kit (Sigma). Participants will complete a GI health questionnaire on a weekly basis to determine tolerance to increased raisin intake.

• Study Type: Interventional
• Enrollment (Actual): 18
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Florida
    • Gainesville, Florida, United States, 32608
      • Emerging Pathogens Institiute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Good Health
• No systemic antibiotics during the preceding two months
• No medication suppressing immune function
• Willingness to provide basic demographic as well as medical history data

Exclusion Criteria:

• Gastric Ulcers
• Inflammatory Bowel Disease (IBD) or Irritable Bowel Syndrome (IBS)
• Chronic constipation/diarrhea
• Body Mass Index (BMI) > 30
• Dietary restrictions that prevent legume intake
• Currently on any medication that can affect GI transit time
• Consumption of >3 servings/week of raisins BEFORE study begins

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Raisins Enhanced Diet; Participants will be provide with a Raisin Enhanced Diet over a short term period of time.	Other: Raisins; Participants will consume 84g of raisins per day for 14 days.; Other Names: Sun-Maid California Raisins

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in diversity of gut microbiota 16S rRNA gene sequences with regard to time.	Compare the overall gut microbial diversity of individual subjects before and after the implementation of a controlled and observed diet of raisins, using 16S ribosomal RNA (rRNA) sequencing of fecal samples.	Change in Baseline (Day 1), Day 9, and Day 14

Collaborators and Investigators

• Sponsor: University of Florida
• Collaborators: Sun-Maid Growers of California
• Investigators: Principal Investigator: Volker Mai, PhD, MPH, Associate Professor

Publications and helpful links

General Publications

• Wijayabahu AT, Waugh SG, Ukhanova M, Mai V. Dietary raisin intake has limited effect on gut microbiota composition in adult volunteers. Nutr J. 2019 Mar 7;18(1):14. doi: 10.1186/s12937-019-0439-1.

Study record dates

Study Major Dates

• Study Start: January 1, 2016
• Primary Completion (Actual): May 1, 2016
• Study Completion (Actual): June 1, 2016

Study Registration Dates

• First Submitted: March 15, 2016
• First Submitted That Met QC Criteria: March 15, 2016
• First Posted (Estimate): March 18, 2016

Study Record Updates

• Last Update Posted (Actual): September 11, 2017
• Last Update Submitted That Met QC Criteria: September 7, 2017
• Last Verified: September 1, 2017

More Information

Terms related to this study

• Keywords: Gut Microbiota
• Additional Relevant MeSH Terms: Pathologic Processes; Inflammation
• Other Study ID Numbers: IRB201500607

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No