Diet, Insulin Sensitivity, and Postprandial Metabolism (TEF)
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|ClinicalTrials.gov Identifier: NCT02939638|
Recruitment Status : Completed
First Posted : October 20, 2016
Last Update Posted : March 20, 2019
|Condition or disease||Intervention/treatment||Phase|
|Overweight Obesity Insulin Resistance||Other: Plant-based diet Other: Control Diet||Not Applicable|
In a 16-week trial, overweight adults will be randomly assigned to two groups. Changes in beta-cell function will be the primary outcome. Changes in insulin sensitivity will be the secondary outcome. Changes in postprandial metabolism, and body weight will be the tertiary outcomes.
The Diet Group will be asked to follow a low-fat, vegan diet and will receive weekly classes and support.
The Control Group will be asked to follow a conventional control diet..
This study conducts a pilot substudy to test the hypothesis that changes in insulin sensitivity and beta-cell function observed in response to a diet intervention correlate with changes in intramyocellular and/or intrahepatocellular lipid. Another sub-study assesses the association between metabolic outcomes and gut microbiome. One additional sub-study is looking for associations between metabolic outcomes and endothelial function.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||220 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||None (Open Label)|
|Official Title:||A Randomized, Controlled Trial on Diet, Insulin Sensitivity, and Postprandial Metabolism|
|Actual Study Start Date :||October 2016|
|Actual Primary Completion Date :||December 2018|
|Actual Study Completion Date :||January 9, 2019|
Active Comparator: Plant-based diet
The diet group will be asked to follow a low-fat, vegan diet for 16 weeks
Other: Plant-based diet
Weekly instructions will be given to the participants in the intervention group about following vegan diet.
Other Name: Vegan diet
Active Comparator: Control diet
Half of the participants will be asked to continue their usual diets for the 16-week study period.
Other: Control Diet
Participants will be asked to continue their usual diets for the 16-week study period.
- Beta-cell function [ Time Frame: 16 weeks ]A 3-hour standard meal test will be performed after an overnight fast. Glucose, insulin and C-peptide will be measured at 0, 30, 60, 120, and 180 min.
- Insulin resistance [ Time Frame: 16 weeks ]Insulin resistance will be assessed by the HOMA index.
- Resting Energy Expenditure (REE) and postprandial metabolism [ Time Frame: 16 weeks ]
Participants will be asked to report to the laboratory within 60 minutes of waking and after a 12-hour fast. Following 30 minutes of quiet rest in a dimly lit room, pulse, respiratory rate, and body temperature will be measured. REE will be measured for 20 minutes through indirect calorimetry (Cosmed Quark RMR, Chicago, IL) utilizing a ventilated hood system. The laboratory temperature will be maintained at 23 degrees C throughout, and precautions will be taken to minimize any disturbances that could affect the metabolic rate.
For premenopausal women, measures will be timed so as to occur in the luteal phase of the menstrual cycle. Postprandial metabolism will be measured for three hours after the standard meal.
- Body weight [ Time Frame: 16 weeks ]Anticipated weight-loss for intervention group compared with control group.
- Changes in intramyocellular and/or intrahepatocellular lipid [ Time Frame: 16 weeks ]A subset of participants will be selected for MR spectroscopy studies quantifying hepatic lipid and/or intramyocellular and/or contents in order to provide data regarding possible causal relationships between dietary changes, ectopic lipid, and insulin sensitivity. Selected individuals with varying degrees of insulin-resistance in both groups will be assessed before and after the intervention period. These MRS studies will take place at the Magnetic Research Center at Yale University School of Medicine, New Haven, CT.
- Microbiome Analysis [ Time Frame: 16 weeks ]Microbiome analysis from participant-provided stool sample. Analysis from uBiome in a subset of participants. Anticipated changes in the dietary intervention group include changes in the microbiome composition that correlate with changes in insulin sensitivity.
- Endothelial function [ Time Frame: 16 weeks ]Endothelial function will be measured using the EndoPAT in a subset of participants.
- Diet Assessment Recall Questionnaire [ Time Frame: 16 weeks ]24-hour multi-pass dietary recalls will be used to assess dietary adherence to assist study personnel in working with individuals who need additional teaching or support.
- The Effect of Fat Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion [ Time Frame: 16 Weeks ]Regression Analysis will be used to assess The Effect of Fat Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion
- The Effect of Carbohydrate Quantity & Quality on Body Composition & Insulin Resistance [ Time Frame: 16 Weeks ]Regression Analysis will be used to assess The Effect of Carbohydrate Quantity & Quality on Body Composition & Insulin Resistance
- The Effect of Protein Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion [ Time Frame: 16 Weeks ]Regression Analysis will be used to assess The Effect of Protein Quantity & Quality on Body Composition, Insulin Resistance, & Insulin Secretion
- Levels of Advanced Glycosylation Endproducts (AGEs) [ Time Frame: 16 Weeks ]An AGE reader will be used to measure the Levels of the AGEs in the skin
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02939638
|United States, District of Columbia|
|Physicians Committee for Responsible Medicine|
|Washington, District of Columbia, United States, 20016|
|Principal Investigator:||Neal D Barnard, M.D.||President|