Effect of Dietary Flavonoids on Intestinal Microbiota, Intestinal Inflammation and Metabolic Syndrome

Not Applicable

Completed

• Conditions: Inflammation; Metabolic Syndrome X
• Interventions: Other: High Dietary Flavonoids; Other: Low Dietary Flavonoids

• Registration Number: NCT02728570
• Lead Sponsor: Utah State University

Brief Summary

The investigators have hypothesized that dietary flavonoids reduce insulin resistance and subclinical inflammation secondary to reductions in intestinal inflammation and permeability and that these events are mediated through alterations in gut microbiota composition. To test this hypothesis, 30 overweight/obese men and women will be provided two well-controlled diets that are identical in macronutrient content (Protein, 17% en; Fat, 30% en; Carbohydrate, 53% en), but differ markedly in flavonoid content (Low Flavonoid Diet, 10 mg/1000 Kcals; High Flavonoid Diet, 340 mg/1000 Kcals). All meals for both diets will be prepared and fed for 6 weeks each in a randomized cross-over design with endpoints determined in duplicate during the last week of each diet period.

Detailed Description

Not available

Study Timeline

• Study Start: 2013-11
• Primary Completion: 2015-03
• Study Completion: 2015-10
• Study First Submitted: 2016-03-30
• Study First Submitted QC: 2016-03-30
• Status Verified: 2016-04
• Study First Posted: 2016-04-05
• Last Update Submitted: 2016-04-14
• Last Update Posted: 2016-04-15

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

• BMI between 25 and 35 kg/m2

Exclusion Criteria

• Documented presence of atherosclerotic disease;
• Diabetes mellitus
• Uncontrolled hypertension
• Renal, hepatic, endocrine, gastrointestinal or other systemic disease
• For women, pregnancy, breast feeding or postpartum < 6 months
• History of drug or alcohol abuse
• History of depression or mental illness requiring hospitalization within the last 12 months
• Use of antibiotics within the last 6 months
• Multiple food allergies or significant food preferences or restrictions that would interfere with diet adherence
• Chronic use of over-the-counter medication which would interfere with study endpoints including NSAIDS, laxatives and antacids
• Lifestyle or schedule incompatible with the study protocol
• Other medical, psychiatric, or behavioral conditions that in the view of the principal investigator may present a safety hazard to the participant or interfere with study participation or the ability to follow the intervention protocol.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
High Flavonoids then Low Flavonoids	High Dietary Flavonoids	Participants receive a prepared diet with High Dietary Flavonoids (340 mg of flavonoids/1000 Kcals) for six weeks. After a minimum washout period of 2 weeks, participants receive a prepared diet with Low Dietary Flavonoids (10 mg of flavonoids/1000 Kcals) for six weeks.
Low Flavonoids then High Flavonoids	High Dietary Flavonoids	Participants receive a prepared diet with Low Dietary Flavonoids (10 mg of flavonoids/1000 Kcals) for six weeks. After a minimum washout period of 2 weeks, participants receive a prepared diet with High Dietary Flavonoids (340 mg of flavonoids/1000 Kcals) for six weeks.
Low Flavonoids then High Flavonoids	Low Dietary Flavonoids	Participants receive a prepared diet with Low Dietary Flavonoids (10 mg of flavonoids/1000 Kcals) for six weeks. After a minimum washout period of 2 weeks, participants receive a prepared diet with High Dietary Flavonoids (340 mg of flavonoids/1000 Kcals) for six weeks.
High Flavonoids then Low Flavonoids	Low Dietary Flavonoids	Participants receive a prepared diet with High Dietary Flavonoids (340 mg of flavonoids/1000 Kcals) for six weeks. After a minimum washout period of 2 weeks, participants receive a prepared diet with Low Dietary Flavonoids (10 mg of flavonoids/1000 Kcals) for six weeks.

Primary Outcome Measures

Name	Time	Method
Fecal calprotectin	6 weeks	Primary endpoint for intestinal inflammation
Serum C-reactive protein	6 weeks	One of two primary endpoints for systemic inflammation
Serum soluble tumor necrosis factor receptor-1	6 weeks	One of two primary endpoints for systemic inflammation
Serum insulin	6 weeks	Primary endpoint for insulin resistance

Secondary Outcome Measures

Name	Time	Method
Fecal microbiome composition	6 weeks	Includes relative abundances of operational taxonomic units and assigned taxonomy as well as alpha and beta diversity measurements
Fecal short chain fatty acids	6 weeks	Measure of fecal microbiome metabolic capabilities and includes acetate, propionate, butyrate, valerate and caproate.
Fecal eosinophil protein X	6 weeks	Secondary endpoint for intestinal inflammation
Fecal myeloperoxidase	6 weeks	Secondary endpoint for intestinal inflammation
Intestinal permeability by four sugar differential absorption test	6 weeks	Secondary endpoint for intestinal inflammation
Serum endotoxin	6 weeks	Secondary endpoint for intestinal inflammation
Serum interleukin-6	6 weeks	Secondary endpoint for systemic inflammation
Serum soluble tumor necrosis factor receptor-2	6 weeks	Secondary endpoint for systemic inflammation
Serum fasting glucose	6 weeks	Secondary endpoint for insulin resistance
Calculated Homeostatic Model Assessment-Insulin Resistance	6 weeks	Secondary endpoint for insulin resistance
Serum C-peptide	6 weeks	Secondary endpoint for insulin resistance
Plasma lipids	6 weeks	Secondary endpoint for insulin resistance. Includes LDL-cholesterol, HDL-cholesterol and triglycerides
Blood pressure	6 weeks	Secondary endpoint for insulin resistance. Includes systolic and diastolic blood pressure

Trial Locations

Locations (1)

Utah State University, Center for Human Nutrition Studies; 🇺🇸 Logan, Utah, United States