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 the management of type 1 diabetes in adults. The primary outcome measure of this study is insulin requirements (measured as the total daily dose (TDD) of insulin or basal and bolus insulin units injected per day). The study duration is 12 weeks.
Type 1 diabetes is a chronic autoimmune disorder characterized by loss of β-cell mass and function in the pancreas, leading to reduced secretion of insulin and hyperglycemia. The management of type 1 diabetes requires the administration of exogeneous insulin. Total daily dose (TDD) of insulin, a measure of the total amount of exogeneous insulin utilized per day, can be affected by multiple factors including insulin resistance, carbohydrate intake, body weight, and body composition. While the pathogenesis of type 1 diabetes and type 2 diabetes differ, a low-fat, plant-based diet has been shown to reduce insulin resistance, reduce body weight, improve body composition, and improve glycemic control in individuals with type 2 diabetes. A low-fat, plant-based diet has also been shown to improve β-cell function in individuals who are overweight. This finding is consistent with other research that shows that therapies that reduce body fat, or modify the distribution of body fat, improve β-cell function and glucose homeostasis. To date, a low-fat, plant-based diet has never been adequately tested in adults with type 1 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 insulin requirements in adults with type 1 diabetes. Using a parallel group design, participants with type 1 diabetes will be randomly assigned to follow a low-fat, plant-based diet or a portion-controlled diet (compliant with current ADA guidelines) for 12 weeks. The principal dependent measures of this study are TDD of insulin, hemoglobin A1c (HbA1c), interstitial fluid glucose levels, and 24-hour carbohydrate: insulin ratio. Secondary and tertiary dependent measures include inflammatory biomarkers, blood lipids, body weight, diet quality, diet acceptability, and medication use. The investigators hypothesize that both the low-fat, plant-based dietary intervention and the portion-controlled dietary intervention will elicit changes in insulin requirements, HbA1c, variability in interstitial glucose levels, insulin sensitivity, and body weight in participants with type 1 diabetes. The investigators further hypothesize that the low-fat, plant-based dietary intervention will confer a more substantial effect on changes in insulin requirements, HbA1c, insulin sensitivity, variability in interstitial glucose levels, and body weight in participants with type 1 diabetes.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
35
Low-fat, plant-based diet
Portion-controlled diet (compliant with ADA guidelines)
Physicians Committee for Responsible Medicine
Washington D.C., District of Columbia, United States
Total Insulin Dose
A sum of basal and bolus insulin units (U) injected per day. An average from three (3) days (two (2) workdays and one (1) weekend day) will be utilized.
Time frame: Change from week 0 to week 12
Glycemic Control
Hemoglobin A1c (HbA1c), an index of glycemic control, will be utilized.
Time frame: Change from week 0 to week 12
Glycemic Variability
Glycemic variability will be assessed through use of a continuous glucose monitoring (CGM) system that will measure the concentration of glucose in the interstitial fluid. Participants will be instructed to wear a CGM (Dexcom g6 Platinum CGM System with an enhanced algorithm, software 505, Dexcom, Inc.) and record its readings at preset increments (after an overnight fast, before each meal, 2 hours after each meal, and before going to bed) daily. Participants will be prompted to submit CGM data to investigators on a weekly basis.
Time frame: Change from week 0 to week 12
24-hour Carbohydrate to Insulin Ratio
Calculated as the total number of grams (g) of dietary carbohydrate to total units (U) of insulin administered.
Time frame: Change from week 0 to week 12
Body Weight
Change in body weight measured on a calibrated scale.
Time frame: Change from week 0 to week 12
Concentration of Plasma Lipids
Change in plasma cholesterol \& triglycerides.
Time frame: Change from week 0 to week 12
High-sensitivity C-reactive Protein (hs-CRP)
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Implemented as a biomarker for absolute cardiovascular disease risk prediction.
Time frame: Change from week 0 to week 12
Tumor necrosis factor - α (TNF-α)
Implemented to assess levels of systemic inflammation.
Time frame: Change from week 0 to week 12
Interleukin (IL) - 1 (IL-1) and interleukin-6 (IL-6)
Implemented to assess levels of systemic inflammation.
Time frame: Change from week 0 to week 12
Food costs
Food costs will be assessed, using the U.S. Department of Agriculture Thrifty Food Plan, 2021, at baseline and 12 weeks.
Time frame: 12 weeks
Insulin costs
Insulin costs will be assessed, using the Federal Supply Schedule (FSS) for insulin prices, at baseline and 12 weeks.
Time frame: 12 weeks