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

NCT04944316 | Completed DMC

• 1 other identifier: Pro00048903
• Study Type: interventional
• Target: 35
• Locations: 1 country
• Sites: 1

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.

Conditions

Diabetes Mellitus, Type 1

Outcome Measures

Primary Outcomes (4)

• 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.

  Change from week 0 to week 12

• Glycemic Control

  Hemoglobin A1c (HbA1c), an index of glycemic control, will be utilized.

  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.

  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.

  Change from week 0 to week 12

Secondary Outcomes (7)

• Body Weight

  Change from week 0 to week 12

• Concentration of Plasma Lipids

  Change from week 0 to week 12

• High-sensitivity C-reactive Protein (hs-CRP)

  Change from week 0 to week 12

• Tumor necrosis factor - α (TNF-α)

  Change from week 0 to week 12

• Interleukin (IL) - 1 (IL-1) and interleukin-6 (IL-6)

  Change from week 0 to week 12

Other Outcomes (3)

• Medication Use

  Change from week 0 to week 12

• Diet Quality

  Change from week 0 to week 12

• Diet Acceptability

  Change from week 0 to week 12

Study Arms (2)

Low-fat, vegan diet

ACTIVE COMPARATOR

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.

Behavioral: Dietary intervention

Portion-controlled diet

ACTIVE COMPARATOR

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.

Behavioral: Dietary intervention

Interventions

Dietary intervention BEHAVIORAL

Low-fat, plant-based diet

Low-fat, vegan diet

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Type 1 diabetes
• Men and women ≥ 18 years of age
• Stable insulin regimen for past 3 months

You may not qualify if:

• Type 2 or gestational diabetes
• Body mass index ≥ 40 kg/m2
• HbA1c ≥ 12.0%
• Smoking or drug abuse during the past six months
• 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
• Unstable medical or psychiatric illness
• Already following a low-fat vegan diet
• Pregnant or breastfeeding, or plans of pregnancy within the study period
• Lack of English fluency
• Unable or unwilling to participate in all components of the study
• Evidence of an eating disorder

Sponsors & Collaborators

• Physicians Committee for Responsible Medicine: lead

Study Sites (1)

Physicians Committee for Responsible Medicine

Washington D.C., District of Columbia, 20016, United States

Location

Related Publications (14)

• 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.

  PMID: 18175767 BACKGROUND

• 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.

  PMID: 1659172 BACKGROUND

• 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.

  PMID: 29382975 BACKGROUND

• 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.

  PMID: 12830019 BACKGROUND

• 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.

  PMID: 12900694 BACKGROUND

• 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.

  PMID: 11815483 BACKGROUND

• 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.

  PMID: 22673566 BACKGROUND

• 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.

  PMID: 12778049 BACKGROUND

• 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.

  PMID: 7842153 BACKGROUND

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

  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

  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.

  PMID: 41088465 DERIVED

• 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 Nov;35(11):104197. doi: 10.1016/j.numecd.2025.104197. Epub 2025 Jun 13.

  PMID: 40651893 DERIVED

• 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.

  PMID: 40474900 DERIVED

MeSH Terms

Conditions

Diabetes Mellitus, Type 1

Interventions

Diet Therapy

Condition Hierarchy (Ancestors)

Diabetes Mellitus; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases; Autoimmune Diseases; Immune System Diseases

Intervention Hierarchy (Ancestors)

Nutrition Therapy; Therapeutics

Study Officials

• Hana Kahleova, MD, PhD

  Physicians Committee for Responsible Medicine

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: CARE PROVIDER
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 21, 2021
• First Posted: June 29, 2021
• Study Start: January 19, 2022
• Primary Completion: November 9, 2022
• Study Completion: November 9, 2022
• Last Updated: September 27, 2024

Record last verified: 2024-02

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)