The Effect of a Low-fat Vegan Dietary Intervention on Intracellular Lipid, Insulin Sensitivity, and Glycemic Control in Type 2 Diabetes

February 22, 2024 updated by: Physicians Committee for Responsible Medicine
The goal of this 16-week clinical trial is to assess the health benefits of a low-fat vegan diet on insulin sensitivity and glycemic control in type 2 diabetes. Participants will receive at no cost, study-related weekly nutrition education classes and one-on-one consultation with a registered dietitian.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This study tests the hypothesis that fat content in muscle and liver cells will be reduced and changes in insulin sensitivity will be observed in response to a low-fat vegan diet intervention.

The study will be carried out online (via Zoom or a similar platform). Participants will be asked to attend weekly online classes on nutrition and health.

The study will also require in-person meetings. Participants will travel to the Physicians Committee of Responsible Medicine, Washington, DC, at the beginning of the study (week 0) and the end of the study (week 16) to complete bloodwork (comprehensive metabolic panel, lipid panel, and HbA1c) and several medical tests (standard meal test, indirect calorimetry, dual-energy x-ray absorptiometry [DEXA Scan, an imaging test that measures changes in bone mineral density/bone strength], and Advanced Glycation End-products measurement). They will also need to travel to the Magnetic Research Center at Yale University School of Medicine, New Haven, CT at the beginning of the study (week 0) and the end of the study (week 16) to have a Magnetic Resonance (MR) spectroscopy to quantify liver and muscle fat content.

Study Type

Interventional

Enrollment (Estimated)

20

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • District of Columbia
      • Washington, District of Columbia, United States, 20016
        • Recruiting
        • Physicians Committee for Responsible Medicine
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Men and women with type 2 diabetes treated by diet and/or oral hypoglycemic agents other than sulfonylureas
  2. Age ≥18 years
  3. Body mass index 26-40 kg/m2
  4. Medications (antidiabetic, antihypertensive, and lipid-lowering) have been stable for the past 3 months
  5. HbA1c between 6.0-10.5% (42-91 mmol/mol)

Exclusion Criteria:

  1. Diabetes mellitus, type 1 and/or treatment with insulin or sulfonylureas
  2. Metal implants, such as a cardiac pacemaker or an aneurysm clip
  3. History of any endocrine condition that would affect body weight, such as thyroid disease, pituitary abnormality, or Cushing's syndrome
  4. Smoking 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. Use of recreational drugs in the past 6 months
  7. Use within the preceding six months of medications that affect appetite or body weight, such as estrogens or other hormones, thyroid medications, systemic steroids, antidepressants (tricyclics, monoamine oxidase inhibitors, selective serotonin reuptake inhibitors), antipsychotics, lithium, anticonvulsants, appetite suppressants or other weight-loss drugs, herbs for weight loss or mood, St. John's wort, ephedra, beta-blockers
  8. Pregnancy or intention to become pregnant during the study period
  9. Unstable medical or psychiatric illness
  10. Evidence of an eating disorder
  11. Likely to be disruptive in group sessions
  12. Already following a low-fat, vegan diet
  13. Lack of English fluency
  14. Inability to maintain current medication regimen
  15. Inability or unwillingness to participate in all components of the study
  16. Intention to follow another weight-loss method during the trial

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Intervention Group: low-fat vegan diet
This arm of participants will be asked to attend weekly online classes in nutrition and health and to follow a low-fat, vegan diet for 16 weeks.
Behavioral: low-fat vegan diet
The intervention diet consists of whole grains, vegetables, legumes, and fruits, with no restriction on energy intake. Participants will also be guided to favor foods with a low glycemic index. Animal products and added oils will be excluded. The diet is designed to derive approximately 10% of energy from fat, approximately 10-15% of energy from protein, and the remainder from mostly complex carbohydrates. The diet will also provide approximately 40 g of fiber per day.
Other Names:
  • low-fat, plant-based diet

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Intramyocellular and Hepatocellular Lipid Content
Time Frame: 16-weeks
MR spectroscopy will be used to quantify liver and muscle fat content. This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in intramyocellular and hepatocellular lipid content.
16-weeks
Insulin sensitivity and β-cell function
Time Frame: 16-weeks
These 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, immunoreactive insulin, and C-peptide will be measured at 0, 30, 60, 120, and 180 min. Insulin secretory rates will be calculated from plasma C-peptide levels by deconvolution49 and expressed per square meter of estimated body surface area. This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in insulin sensitivity and β-cell function.
16-weeks
Resting energy expenditure and postprandial metabolism
Time Frame: 16-weeks
This 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. Resting energy expenditure will be measured for 20 minutes through indirect calorimetry, utilizing a ventilated hood system. Postprandial metabolism will be measured for 20 minutes in the last hour of the meal test, i.e. 2 hours after the standard breakfast. This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in resting energy expenditure and postprandial metabolism.
16-weeks
Body Composition
Time Frame: 16-weeks
This will be measured by dual-energy x-ray absorptiometry (Lunar iDXA). The iDXA can measure body composition with low X-ray exposure and short scanning time. This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in body composition.
16-weeks
Advanced Glycation End-products (AGE)
Time Frame: 16-weeks
This will be measured using the Advanced Glycation End-products (AGE) Reader made by Diagnoptics. AGE Reader measures the skin fluorescence to quantify the tissue accumulation of AGE's. This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in advanced glycation end-products (AGE).
16-weeks
Continuous glucose monitoring
Time Frame: 16-weeks
To provide glucose readings throughout the day, participants will be provided with a continuous glucose monitoring (CGM) system that measures glucose concentrations between 40 and 400 mg/dL every 5 minutes for up to 7 days by sampling interstitial fluid. The participants who are at risk of hypoglycemia will be encouraged to use CGM throughout the whole study.
16-weeks
Body Weight
Time Frame: 16-weeks
This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in body weight.
16-weeks
Plasma Lipid Concentrations
Time Frame: 16-weeks
This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in plasma lipid concentrations.
16-weeks
HbA1c
Time Frame: 16-weeks
This study will assess the association of attending a series of plant-based nutrition classes with pre-post changes in glycemic control in individuals with type 2 diabetes as assessed by hemoglobin A1c (HbA1c) and use of medication.
16-weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Diet Quality
Time Frame: 16-weeks
In addition, this study will assess the association between attending a series of plant-based nutrition classes on pre-post changes in diet quality. Diet quality will be determined using the alternate eating index.
16-weeks
Food Acceptability
Time Frame: 16-weeks
This study will assess the association between attending a series of plant-based nutrition classes on pre-post changes in food acceptability. The Food Acceptability Questionnaire (FAQ) will measure attitudes about the intervention diet, the effort required to follow it, and the likelihood of continued adherence to it in the future.
16-weeks
Food Cost
Time Frame: 16-weeks
This study will assess the association between attending a series of plant-based nutrition classes on pre-post changes in food cost. The food cost will be determined using the 3-day diet records and the United States Department of Agriculture (USDA) Thrifty Plan 2021.
16-weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Physicians Committee for Responsible Medicine

Collaborators

Yale University

Investigators

  • Principal Investigator: Hana Kahleova, MD, PhD, Physicians Committee for Responsible Medicine

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 13, 2024

Primary Completion (Estimated)

December 1, 2025

Study Completion (Estimated)

December 1, 2025

Study Registration Dates

First Submitted

October 24, 2023

First Submitted That Met QC Criteria

October 24, 2023

First Posted (Actual)

October 30, 2023

Study Record Updates

Last Update Posted (Actual)

February 26, 2024

Last Update Submitted That Met QC Criteria

February 22, 2024

Last Verified

February 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Pro00074571

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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