Impact of Blueberry Consumption on Gastrointestinal Health

Not Applicable

Completed

• Conditions: Obesity; Circadian Dysregulation
• Interventions: Dietary Supplement: Placebo powder; Dietary Supplement: Blueberry powder

• Registration Number: NCT03934177
• Lead Sponsor: University of Nebraska Lincoln

Brief Summary

This study will evaluate the impact of blueberry consumption on markers of gastrointestinal health including gut microbiota, intestinal permeability, and gut-derived inflammation in those vulnerable to a unhealthy gut milieu. All participants will consume a blueberry powder and a placebo in this crossover study.

Detailed Description

The commensal bacteria that reside in the human gut, known as the gut microbiota, is a complex system that modulates local gut homeostasis and systemic biological processes. Several environmental factors have been shown to influence the gut milieu (including microbiota), and thus both gastrointestinal and host health. Relevant to the current proposal is the influence of body weight, diet, and circadian rhythms. In the current study, the investigators propose to use these common disruptors of gastrointestinal health through recruiting obese shift workers with a low-fiber diet to identify if these disrupted individuals can benefit from blueberry intake. Specifically, the study objectives are to determine if 24 g whole blueberry powder consumed daily can beneficially modify intestinal permeability, gut microbiota, microbial metabolites, and both gut-derived and systemic inflammation in those most susceptible to a pro-inflammatory milieu. This will be accomplished through a 14-week crossover study in which 28 individuals will be randomized by treatment group order to 4 weeks of whole blueberry powder and placebo powder, with a 4-week wash out in between the treatment periods.

Study Timeline

• Study Start: 2019-03-26
• Study First Submitted: 2019-04-15
• Study First Submitted QC: 2019-04-28
• Study First Posted: 2019-05-01
• Status Verified: 2023-03
• Primary Completion: 2023-03-02
• Study Completion: 2023-03-02
• Last Update Submitted: 2023-03-20
• Last Update Posted: 2023-03-22

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 28

Inclusion Criteria

• obese (BMI +/- 30.0 kg/m2)
• shift workers (shift work overnight (third shift) +/= 3 days/week for the past 3 months)
• 19-70 years of age

Exclusion Criteria

• patient history of gastrointestinal diseases except for hiatal hernia, GERD, or hemorrhoids, mild gastrointestinal symptoms
• elevated laboratory values from a comprehensive metabolic panel (CMP) and complete blood count (CBC) with the exception of glucose (+/= 126 mg/dL; if elevated, confirmed with HA1c of greater than or equal to 6.5%) and ALT, AST, or ALP over 2 times normal levels (to allow for mild elevations resulting from fatty liver often seen in obese) unless approved by study physician
• currently pregnant or plans to become pregnant during the study as determined by participant report
• antibiotic use within the last 12 weeks prior to enrollment
• presence of chronic metabolic disease (e.g., cardiovascular disease, diabetes, cancer) or per physician discretion
• recent (past 4 weeks) major change in dietary habits or a plan to have a major change in dietary habits during the study
• habitual blueberry consumption of more than 0.5 cups 2x/week or a 4-week washout period if consumes
• allergy or intolerance to blueberries
• consumption of supplemental fiber, probiotics or prebiotics without an appropriate 4-week washout period
• restrictive dietary patterns (e.g., ketogenic, Paleolithic) or a diet high in fiber (+/= 14 g/1000 kilocalories) to increase study result generalizability to the U.S. population (low-fiber diet), as well as provide another stimuli for gut leakiness
• unwillingness to consent to the study.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Placebo powder	Placebo powder	4 weeks of supplementation of 24 g placebo powder (maltodextrin)
Blueberry powder	Blueberry powder	4 weeks of supplementation of 24 g whole blueberry powder

Primary Outcome Measures

Name	Time	Method
intestinal permeability	28 days	urinary sugar measurement by gas chromatography (GC): Sucralose, lactulose, mannitol, sucrose as a percent of oral dose.

Secondary Outcome Measures

Name	Time	Method
Microbiota	28 days	Microbiota composition through shotgun sequencing. Composition includes relative abundance of all microbes in stool.
Microbial metabolites	28 days	Quantity of stool short-chain fatty acid (butyrate, propionate, acetate) per dry stool weight by gas chromatography
Gut-derived/systemic inflammation	28 days	Concentration of serum lipopolysaccharide (LPS), LPS-binding protein (LBP), and interleukin-6 (IL6)

Trial Locations

Locations (2)

University of Nebraska; 🇺🇸 Lincoln, Nebraska, United States

University of Nebraska Medical Center; 🇺🇸 Omaha, Nebraska, United States