The Effect of Whole Grain on Gut Microbiome and Metabolic Health

University of Copenhagen60 enrolled

Overview

Objective: To identify how specific changes of the whole grain 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 intervention periods, separated by a 6-week wash-out period. A total of 60 participants will be included. Intervention: low vs. high whole grain 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 diet rich in whole grain in the active treatment period and a refined grain diet during the control period. Measurements: Insulin sensitivity will be assessed by means of a meal challenge test and by the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) which is the primary outcome of this study. Secondary outcomes include metabolic and inflammatory markers, appetite hormones, transit time, and GM composition. Furthermore, selected control measures are included; 4-day food records and a study intervention diary.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Masking

SINGLE

Enrollment

Conditions

Metabolic Disease Injury of Gastrointestinal Tract

Interventions

Whole grainOTHER

Whole grain diet: Participants consume more than 75g of whole grain per day (corresponds to the whole grain intake of the 90th percentile of the population)

Refined grainOTHER

Refined grain diet: Participants consume less than 10 g of whole grain per day (corresponds to the whole grain intake below the 10th percentile of the population)

Eligibility

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

Medical Language ↔ Plain English

Inclusion Criteria: * Body mass index (BMI): 25 - 35 kg/m2 * No medical prescribed diet * Weight stable * No blood donation during the study * Intense sporting activities less than 10h/ week * Alcohol consumption less than 14 units/ week (female) and 21 units/ week (male) * Signed written consent Exclusion Criteria: * Pharmacological treatment; hypertension, 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 * Intake of vitamin, mineral, or pre- or probiotic supplements for 1 month prior to study start * Blood hemoglobin \< 7.0 mmol/l * Blood donation within 1 month prior to study start

Locations (1)

Department of Human Nutrition, University of Copenhagen

Fredriksberg, Denmark

Outcomes

Primary Outcomes

HOMA-IR

Homeostasis Model Assessment of fasting Insulin Resistance (HOMA-IR: glucose (mmol/l( x insulin (pmol/l)/22.5)