Effect of a Dietary Intervention on Intracellular Lipid Levels, Insulin Sensitivity, and Glycemic Control in Type 2 Diabetes
- Conditions
- Diabetes Mellitus, Type 2
- Interventions
- Behavioral: Dietary intervention
- Registration Number
- NCT04088981
- Lead Sponsor
- Physicians Committee for Responsible Medicine
- Brief Summary
The purpose of this study is to compare the effects of a low-fat, plant-based dietary intervention and a portion-controlled dietary intervention (compliant with current American Diabetes Association (ADA) guidelines) on changes in intramyocellular and hepatocellular lipid content in adults with type 2 diabetes. Changes in insulin sensitivity and glycemic control will also be assessed in this study. The study duration is 44 weeks.
- Detailed Description
Type 2 diabetes is a disease characterized by discordance between the amount of insulin produced by pancreatic β-cells and the amount of insulin required to overcome insulin resistance in the liver and peripheral tissues. The development of insulin resistance has been strongly associated with the prolonged accumulation of lipids (fats) in the liver cells ("hepatocellular lipid") and muscle cells ("intramyocellular lipid"). Conventional pharmacologic therapeutics for type 2 diabetes, like metformin, are designed to reduce the accumulation of hepatocellular and intramyocellular lipids and, thereby, augment insulin sensitivity. Research has shown that a low-fat, plant-based diet, in which the consumption of lipids is limited, is a similarly effective therapeutic intervention for the reduction of hepatocellular and intramyocellular lipid content and the improvement of insulin sensitivity in type 2 diabetes.
The purpose of this study is to compare the effects of low-fat, plant-based dietary intervention and a portion-controlled dietary intervention (compliant with current American Diabetes Association (ADA) guidelines) on hepatocellular and intramyocellular lipid content in adults with type 2 diabetes. Using a cross-over design, participants with type 2 diabetes will be randomly assigned to start with a plant-based or a portion-controlled diet for 22 weeks. The two groups will then switch to the opposite diet regimen for an additional 22 weeks. Before and after each intervention period, the investigators will measure intramuscular and liver fat content. The investigators will also assess the relationship between these variables, insulin sensitivity, and glycemic control.
The investigators hypothesize that both dietary interventions will result in reductions in intramuscular and liver fat content, and that these changes will be associated with improvements in insulin sensitivity and glycemic control in individuals with type 2 diabetes. The investigators further hypothesize that the low-fat, plant-based dietary intervention will elicit greater changes in intracellular lipid concentration, compared with the portion-controlled dietary intervention.
Recruitment & Eligibility
- Status
- SUSPENDED
- Sex
- All
- Target Recruitment
- 60
Not provided
Not provided
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description Low-fat, vegan diet Dietary intervention For a 22-week period, participants will be asked to follow a low-fat vegan diet which consists of whole grains, vegetables, legumes, and fruits, with no restriction on energy intake. Animal products and added oils will be excluded. In choosing grain products and starchy vegetables (e.g., bread, potatoes), participants will be encouraged to select those retaining their natural fiber and having a glycemic index \<70, using tables standardized to a value of 100 for glucose. Portion-controlled diet Dietary intervention For a 22-week period, participants will be asked to follow a portion-controlled diet which will include individualized diet plans that reduce daily energy intake by 500 kcal for overweight participants, and keep carbohydrate intake reasonably stable over time. It will derive 50% of total energy from carbohydrates, 20% from protein, and less than 30% from fat (≤7% saturated fat), with less than 200 mg/day of cholesterol/day.
- Primary Outcome Measures
Name Time Method Intramyocellular lipid content 1.) Change from week 0 to week 22; 2.) Change from week 22 to week 44 Proton magnetic resonance (MR) spectroscopy at 4T (Bruker) will be implemented to quantify intramyocellular lipid concentrations.
Hepatocellular lipid content 1.) Change from week 0 to week 22; 2.) Change from week 22 to week 44 Proton magnetic resonance (MR) spectroscopy at 4T (Bruker) will be implemented to quantify intramyocellular lipid concentrations.
Insulin sensitivity Change from baseline to 22 weeks and change from 22 weeks to 44 weeks Insulin resistance will be assessed by the Homeostatic Model Assessment (HOMA) PREDIM indexes
Concentration of glucose 1.) Change from week 0 to week 22; 2.) Change from week 22 to week 44 Concentration of glucose will be assessed during a standard meal test (Boost Plus, Nestle, Vevey, Switzerland; 720 kcal, 34% of energy from fat, 16% protein, 50% carbohydrate). Plasma concentrations of glucose will be measured at 0, 30, 60, 120, and 180 min.
Concentration of C-peptide 1.) Change from week 0 to week 22; 2.) Change from week 22 to week 44 Concentration of C-peptide be assessed during a standard meal test (Boost Plus, Nestle, Vevey, Switzerland; 720 kcal, 34% of energy from fat, 16% protein, 50% carbohydrate). Concentration of C-peptide will be measured at 0, 30, 60, 120, and 180 min.
Rate of glycemic control 1.) Change from week 0 to week 22; 2.) Change from week 22 to week 44 Rate of glycemic control will be assessed through HbA1C.
- Secondary Outcome Measures
Name Time Method Resting energy expenditure Change from baseline to 22 weeks and change from 22 weeks to 44 weeks Resting energy expenditure REE (pulse, respiratory rate and body temperature) will be measured for 20 minutes through indirect calorimetry utilizing a ventilated hood system in fasting participants.
Concentration of plasma lipids Change from baseline to 22 weeks and change from 22 weeks to 44 weeks Change in plasma cholesterol \& triglycerides.
Body weight Change from baseline to 22 weeks and change from 22 weeks to 44 weeks Change in body weight measured on a calibrated scale.
Gut microbiome composition Change from baseline to 22 weeks and change from 22 weeks to 44 weeks Quantitative determination of microorganisms and global analysis of microbial diversity from stool sample. The mean of the change between time points in bacteria counts.
Postprandial metabolism Change from Baseline to 22 weeks and change from 22 weeks to 44 weeks Postprandial metabolism will be measured by indirect calorimetry. 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. Resting energy expenditure will be measured for 20 minutes through indirect calorimetry utilizing a ventilated hood system. Postprandial metabolism will be measured four times, 20 minutes each time, over the course of 3 hours after the standard breakfast.
Body Composition Change from baseline to 22 weeks and change from 22 weeks to 44 weeks Body composition will be measured by dual energy x-ray absorptiometry (Lunar iDXA, GE Healthcare; Madison WI), assessing visceral adipose tissue volume and mass.
Trial Locations
- Locations (1)
Physicians Committee for Responsible Medicine
🇺🇸Washington, District of Columbia, United States