The Effect of Gluten on Gut Microbiome and Metabolic Health.

N/ACompletedNCT01719913

University of Copenhagen60 enrolled

Overview

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.

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

Allocation

RANDOMIZED

Masking

NONE

Enrollment

Conditions

Metabolic Diseases Injury of Gastrointestinal Tract

Interventions

High glutenOTHER

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)

Low glutenOTHER

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)

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Locations (1)

The Novo Nordisk Foundation of Basic Metabolic Health, Section for Metabolic Genetics

Copenhagen, Denmark

Outcomes

Primary Outcomes

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.

Time frame: Up to 3 years.

Secondary Outcomes

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.

Time frame: Up to 2 years.

Gastrointestinal permeability.

Lactulose/mannitol ratio in urine after four hours collection following oral intake of lactulose and mannitol.

Time frame: Up to 2 years.

Colonic fermentation

Breath hydrogen after intake of standardized breakfast (30,60,90,120,180 minutes)

Time frame: 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.

Time frame: 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.

Data from ClinicalTrials.gov

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