Diabetes Mellitus, Type 1
Conditions
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 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.
Detailed description
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.
Interventions
BEHAVIORALDietary intervention
Low-fat, plant-based diet
Sponsors
Physicians Committee for Responsible Medicine
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Caregiver)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
1. Type 1 diabetes 2. Men and women ≥ 18 years of age 3. Stable insulin regimen for past 3 months
Exclusion criteria
1. Type 2 or gestational diabetes 2. Body mass index ≥ 40 kg/m2 3. HbA1c ≥ 12.0% 4. Smoking or drug abuse during the past six months 5. Alcohol consumption of more than 2 drinks per day or the equivalent, episodic increased drinking (e.g., more than 2 drinks per day on weekends), or a history of alcohol abuse or dependency followed by any current use 6. Unstable medical or psychiatric illness 7. Already following a low-fat vegan diet 8. Pregnant or breastfeeding, or plans of pregnancy within the study period 9. Lack of English fluency 10. Unable or unwilling to participate in all components of the study 11. Evidence of an eating disorder
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Glycemic Control | Change from week 0 to week 12 | Hemoglobin A1c (HbA1c), an index of glycemic control, will be utilized. |
| 24-hour Carbohydrate to Insulin Ratio | Change from week 0 to week 12 | Calculated as the total number of grams (g) of dietary carbohydrate to total units (U) of insulin administered. |
| Glycemic Variability | Change from week 0 to week 12 | 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. |
| Total Insulin Dose | Change from week 0 to week 12 | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Tumor necrosis factor - α (TNF-α) | Change from week 0 to week 12 | Implemented to assess levels of systemic inflammation. |
| Food costs | 12 weeks | Food costs will be assessed, using the U.S. Department of Agriculture Thrifty Food Plan, 2021, at baseline and 12 weeks. |
| Insulin costs | 12 weeks | Insulin costs will be assessed, using the Federal Supply Schedule (FSS) for insulin prices, at baseline and 12 weeks. |
| Interleukin (IL) - 1 (IL-1) and interleukin-6 (IL-6) | Change from week 0 to week 12 | Implemented to assess levels of systemic inflammation. |
| Body Weight | Change from week 0 to week 12 | Change in body weight measured on a calibrated scale. |
| Concentration of Plasma Lipids | Change from week 0 to week 12 | Change in plasma cholesterol & triglycerides. |
| High-sensitivity C-reactive Protein (hs-CRP) | Change from week 0 to week 12 | Implemented as a biomarker for absolute cardiovascular disease risk prediction. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Medication Use | Change from week 0 to week 12 | Participants will be asked to report changes in their medication use. |
| Diet Acceptability | Change from week 0 to week 12 | The Food Acceptability Questionnaire (FAQ), a self-reported measure, will be implemented to assess the subjective responses (palatability; satisfaction; ease of preparation; financial feasibility; and perceived physical benefits) of participants to their baseline diets and the intervention diet. The FAQ has twelve (12) total questions. Eleven (11) of the questions are scored on a Likert scale (1-7) and one (1) unscored question (physical benefits) will prompt the participant to check all that apply. A higher FAQ score corresponds with a more positive subjective response. |
| Diet Quality | Change from week 0 to week 12 | Dietary intake will be assessed using 3-day dietary records. Participants will be instructed to record all dietary intake for 3 consecutive days, including 2 weekdays and 1 weekend day. Records will be analyzed using Nutrition Data System for Research software version 2018, developed by the Nutrition Coordinating Center (NCC), University of Minnesota, Minneapolis, MN, US. |
Countries
United States
Outcome results
None listed