Effect of a Dietary Intervention on Insulin Requirements in Type 1 Diabetes

NCT ID: NCT04944316

Last Updated: 2024-09-27

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

35 participants

Study Classification

INTERVENTIONAL

Study Start Date

2022-01-19

Study Completion Date

2022-11-09

Brief Summary

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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

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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.

Conditions

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Diabetes Mellitus, Type 1

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

SINGLE

Caregivers

Study Groups

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Low-fat, vegan diet

For a 12-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.

Group Type ACTIVE_COMPARATOR

Dietary intervention

Intervention Type BEHAVIORAL

Low-fat, plant-based diet

Portion-controlled diet

For a 12-week period, participants will be asked to follow a portion-controlled diet that is compliant with American Diabetes Association (ADA) guidelines. This diet will include individualized diet plans that reduce daily energy intake by 500-1,000 kcal for overweight (body mass index \> 25 kg/m2) participants and keep carbohydrate intake reasonably stable over time. It will derive 15-20% from protein, \<7% saturated fat, 60-70% carbohydrate and monounsaturated fats and ≤200 mg/day of cholesterol/day.

Group Type ACTIVE_COMPARATOR

Dietary intervention

Intervention Type BEHAVIORAL

Portion-controlled diet (compliant with ADA guidelines)

Interventions

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Dietary intervention

Low-fat, plant-based diet

Intervention Type BEHAVIORAL

Dietary intervention

Portion-controlled diet (compliant with ADA guidelines)

Intervention Type BEHAVIORAL

Eligibility Criteria

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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
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Physicians Committee for Responsible Medicine

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Hana Kahleova, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Physicians Committee for Responsible Medicine

Locations

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Physicians Committee for Responsible Medicine

Washington D.C., District of Columbia, United States

Site Status

Countries

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United States

References

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Riccardi G, Rivellese AA, Giacco R. Role of glycemic index and glycemic load in the healthy state, in prediabetes, and in diabetes. Am J Clin Nutr. 2008 Jan;87(1):269S-274S. doi: 10.1093/ajcn/87.1.269S.

Reference Type BACKGROUND
PMID: 18175767 (View on PubMed)

Anderson JW, Zeigler JA, Deakins DA, Floore TL, Dillon DW, Wood CL, Oeltgen PR, Whitley RJ. Metabolic effects of high-carbohydrate, high-fiber diets for insulin-dependent diabetic individuals. Am J Clin Nutr. 1991 Nov;54(5):936-43. doi: 10.1093/ajcn/54.5.936.

Reference Type BACKGROUND
PMID: 1659172 (View on PubMed)

American Diabetes Association. Standards of Medical Care in Diabetes-2018 Abridged for Primary Care Providers. Clin Diabetes. 2018 Jan;36(1):14-37. doi: 10.2337/cd17-0119. No abstract available.

Reference Type BACKGROUND
PMID: 29382975 (View on PubMed)

Pastors JG, Franz MJ, Warshaw H, Daly A, Arnold MS. How effective is medical nutrition therapy in diabetes care? J Am Diet Assoc. 2003 Jul;103(7):827-31. doi: 10.1016/s0002-8223(03)00466-8. No abstract available.

Reference Type BACKGROUND
PMID: 12830019 (View on PubMed)

Craig CL, Marshall AL, Sjostrom M, Bauman AE, Booth ML, Ainsworth BE, Pratt M, Ekelund U, Yngve A, Sallis JF, Oja P. International physical activity questionnaire: 12-country reliability and validity. Med Sci Sports Exerc. 2003 Aug;35(8):1381-95. doi: 10.1249/01.MSS.0000078924.61453.FB.

Reference Type BACKGROUND
PMID: 12900694 (View on PubMed)

Mari A, Tura A, Gastaldelli A, Ferrannini E. Assessing insulin secretion by modeling in multiple-meal tests: role of potentiation. Diabetes. 2002 Feb;51 Suppl 1:S221-6. doi: 10.2337/diabetes.51.2007.s221.

Reference Type BACKGROUND
PMID: 11815483 (View on PubMed)

Kahleova H, Mari A, Nofrate V, Matoulek M, Kazdova L, Hill M, Pelikanova T. Improvement in beta-cell function after diet-induced weight loss is associated with decrease in pancreatic polypeptide in subjects with type 2 diabetes. J Diabetes Complications. 2012 Sep-Oct;26(5):442-9. doi: 10.1016/j.jdiacomp.2012.05.003. Epub 2012 Jun 4.

Reference Type BACKGROUND
PMID: 22673566 (View on PubMed)

American Dietetic Association; Dietitians of Canada. Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets. J Am Diet Assoc. 2003 Jun;103(6):748-65. doi: 10.1053/jada.2003.50142.

Reference Type BACKGROUND
PMID: 12778049 (View on PubMed)

Barnard ND, Akhtar A, Nicholson A. Factors that facilitate compliance to lower fat intake. Arch Fam Med. 1995 Feb;4(2):153-8. doi: 10.1001/archfami.4.2.153.

Reference Type BACKGROUND
PMID: 7842153 (View on PubMed)

Becker MH. The health belief model and personal health behavior. Health Educ Monogr. 1974;2:324-508.

Reference Type BACKGROUND

Barnard N, Scialli AR, Bertron P, Hurlock D, Edmonds K. Acceptability of a Therapeutic Low-Fat, Vegan Diet in Premenopausal Women. J Nutr Educ. 2000;32(6):314-319. doi:10.1016/S0022-3182(00)70590-5

Reference Type BACKGROUND

Kahleova H, Maracine C, Znayenko-Miller T, Kuo S, Herman WH, Holubkov R, Barnard ND. Can a vegan diet help people with type 1 diabetes save on insulin? A secondary analysis of a 12-Week randomized clinical trial. BMC Nutr. 2025 Oct 14;11(1):188. doi: 10.1186/s40795-025-01175-2.

Reference Type DERIVED
PMID: 41088465 (View on PubMed)

Kahleova H, Himmelfarb J, Znayenko-Miller T, Jayaraman A, Chiavaroli L, Holubkov R, Barnard ND. Vegan diet, processed foods, and type 1 diabetes: A secondary analysis of a randomized clinical trial. Nutr Metab Cardiovasc Dis. 2025 Jun 13:104197. doi: 10.1016/j.numecd.2025.104197. Online ahead of print.

Reference Type DERIVED
PMID: 40651893 (View on PubMed)

Kahleova H, Fischer I, Smith R, Himmelfarb J, Znayenko-Miller T, Holubkov R, Barnard ND. Plant-based dietary index and body weight in people with type 1 diabetes: a secondary analysis of a randomized clinical trial. Front Nutr. 2025 May 22;12:1605769. doi: 10.3389/fnut.2025.1605769. eCollection 2025.

Reference Type DERIVED
PMID: 40474900 (View on PubMed)

Other Identifiers

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Pro00048903

Identifier Type: -

Identifier Source: org_study_id

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