The Effect of Gluten on Gut Microbiome and Metabolic Health. (3G)

Gut, Grain and Greens (3G): The Effect of Gluten on Gut Microbiome and Metabolic Health.

Objective: To identify how specific changes of the gluten content in the diet affect the host-gut microbiome interactions with implications for metabolic health.

Design: A randomized, controlled, single-blinded, cross-over intervention trial consisting of two 8-week interventions periods, separated by a 6-week wash-out period. A total number of 60 participants will be included.

Intervention: low vs high gluten intake.

Study Overview

• Status: Completed
• Conditions: Metabolic Diseases; Injury of Gastrointestinal Tract
• Intervention / Treatment: Other: Low gluten; Other: High gluten

Detailed Description

The study is designed as a randomized, controlled, single-blinded, cross-over intervention trial consisting of two 8-week interventions periods, separated by a 6-week wash-out period. A total number of 60 participants will be included. Participants consume, in randomized order, a gluten-poor diet (<5 g/d) in the active treatment period and a gluten-rich diet (>25 g/d) during the control period.

Measurements: Altered quantitative metagenomics at bacterial gene- and species levels is the primary outcome of this study. Secondary outcomes include metabolic and inflammatory markers, circulating appetite hormone levels,serum metabolomics, gastrointestinal transit time and intestinal permeability. Furthermore, selected control measures are included; 4-day food records and a study intervention dietary records.

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Denmark
  • Copenhagen, Denmark, 2100
    • The Novo Nordisk Foundation of Basic Metabolic Health, Section for Metabolic Genetics

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria, compulsory:

• Body mass index (BMI): 25 - 35 kg/m2 OR
• Abdominal obesity: waist circumference: men: ≥ 94cm; women: ≥ 80cm
• No medically prescribed diet
• Weight stable
• Intense sporting activities less than 10 h/week
• Alcohol consumption less than 14 units/week (female) and 21 units/week (male)
• Signed informed consent

Inclusion criteria, minimum one of the following:

• Fasting plasma glucose from 6.1 mmol/l to 6.9 mmol/l
• Reduced high density lipoprotein (HDL) cholesterol; HDL ≤ 1.03 mmol/L for men and ≤ 1.29 mmol/L for women
• Increased triglyceride (TG) > 1.3 mmol/L
• Systolic blood pressure > 130 mmHg

Exclusion Criteria:

• Pharmacological treatment; diabetes and blood lipid regulation
• Lactating (or lactating, 6 weeks ago), pregnant (or pregnant, 3 months ago) or wish to become pregnant during the study
• Participation in another biomedical trial 1 month prior to study start
• Diagnosed with any form of diabetes, celiac disease or chronic pancreatitis
• Reported chronic gastrointestinal disorders
• Antibiotic treatment for 3 month prior to study start
• Blood hemoglobin < 7.0 mmol/l
• Blood donation within 1 month prior to study start

Study Plan

How is the study designed?

Design Details

• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Low gluten; Poor gluten diet: Participants consume less than 5g gluten per day (estimated to correspond to a gluten intake below the 10th percentile in the population)	Other: Low gluten; Poor gluten diet: Participants consume less than 5g gluten per day (estimated to correspond to a gluten intake below the 10th percentile in the population)
Placebo Comparator: High gluten; Refined grain/ gluten rich diet : Participants consume more than 25g of gluten per day (estimated to correspond to a gluten intake around the 90th percentile in the population)	Other: High gluten; Refined grain/ gluten rich diet : Participants consume more than 25g of gluten per day (estimated to correspond to a gluten intake around the 90th percentile in the population)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Altered quantitative metagenomics at bacterial gene- and species levels.	Feces samples are collected according to standard operation procedures for subsequent standardized microbial DNA extraction. Microbial DNA will be subjected to sequencing, microbial gene analyses, taxonomy analyses including enterotypes known species and unknown meta-species and functional annotation.	Up to 3 years.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean intestinal transit time	Participants are instructed in swallowing capsules containing different small non-invasive and non-absorbable plastic pellets for 6 consecutive days. On the seventh day they are having an X-ray of the abdomen taken.	Up to 2 years.
Gastrointestinal permeability.	Lactulose/mannitol ratio in urine after four hours collection following oral intake of lactulose and mannitol.	Up to 2 years.
Colonic fermentation	Breath hydrogen after intake of standardized breakfast (30,60,90,120,180 minutes)	Up to 2 years.
Blood pressure and pulse.	Systolic and diastolic blood pressure and heart beat rate are measured after 10 min of rest according to current standard operational procedure with an automatic blood pressure meter. Participants are instructed not to talk during the measurements.	Up to 1 year.
Saliva microbial flora	Saliva is collected after the participants have taken a small piece of paraffin in their mouth and have chewed until the paraffin has turned into one coherent mass (approximately one minute). Participants are swallowing the produced saliva for that minute. After this, and for the next 3 minutes, saliva is collected in a cup and handed over to the study personnel. Saliva is stored at minus 80 degrees for later studies of saliva microbial flora and saliva biochemistry.	Up to 2 years.
Nasal fluid	Nasal fluid is collected by a non-invasive methodology for in vivo measurement of an array of immunological signalling molecules in the nasal airway lining. The method is based on a standardized collection of mucosal airway fluid from both nostrils onto small sheets of filter papers with efficient absorption properties. The technique is highly reproducible, and used for measuring immunological mediators representing the immediate response ability of the mucosal immune system.	Up to 3 years.
Appetite hormones	Glucagon like peptide 1 and 2, Gastric inhibitory polypeptide, peptide YY and Ghrelin.	Up to 3 years.
Celiac disease markers	Levels of gliadin and Immunoglobulin A and G transglutaminase.	Up to 1 year.
Blood lipid profile	Low density Lipoproteins, High density lipoproteins, Total Cholesterol, Very low density lipoproteins and Free fatty acids.	Up to 2 years.
Bioimpedance	Body composition (lean body mass and fat mass) is measured by bio-electrical impedance using multi frequency Quadscan.	Up to 1 year.
Breath hydrogen.	Breath hydrogen measurements are done before the intake of the standardized breakfast (at 30, 60, 90, 120, 180 minutes), as an indicator of colonic fermentation.	Up to 2 years.
Insulin	Fasting insulin and post prandial at 30, 60, 90, 120 and 180 minutes after standardized meal.	Up to 2 years.
Glucose	Fasting glucose and post prandial at 30, 60, 90, 120 and 180 minutes after standardized meal.	Up to 2 years.
C-peptide	Fasting.	Up to 2 years.
Inflammatory makers	High sensitive C-reactive protein, Interleukin 1, 6 and 10, Lipopolysaccharide- binding protein, Tumor necrosis factor - alfa.	Up to 3 years.
Anthropometric characteristics.	Weight, height, sagittal height and waist circumference.	Up to 1 year.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
4 days precoded food diary.	Validated method for dietary registration, based on 2 week and 2 weekend days.	Up to 2 years.
Gastrointestinal symptoms.	Changes from baseline to after intervention in individual gastrointestinal symptoms by validated VAS-questionary.	Up to 2 years.

Collaborators and Investigators

• Sponsor: University of Copenhagen
• Collaborators: Technical University of Denmark
• Investigators: Principal Investigator: Oluf B Pedersen, MD, DMSCi,Professor, University of Copenhagen

Publications and helpful links

General Publications

• Lind MV, Lauritzen L, Vestergaard H, Hansen T, Pedersen O, Kristensen M, Ross AB. One-carbon metabolism markers are associated with cardiometabolic risk factors. Nutr Metab Cardiovasc Dis. 2018 Apr;28(4):402-410. doi: 10.1016/j.numecd.2018.01.005. Epub 2018 Jan 31.

Helpful Links

• Related Info

Study record dates

Study Major Dates

• Study Start: October 1, 2012
• Primary Completion (Actual): November 1, 2013
• Study Completion (Actual): November 1, 2013

Study Registration Dates

• First Submitted: October 24, 2012
• First Submitted That Met QC Criteria: October 30, 2012
• First Posted (Estimate): November 1, 2012

Study Record Updates

• Last Update Posted (Estimate): December 5, 2013
• Last Update Submitted That Met QC Criteria: December 4, 2013
• Last Verified: December 1, 2013

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Metabolic Diseases
• Other Study ID Numbers: NNF-CBMR 3861-34275