Practice Based Nutrition Intervention-2 (PBNI-2)

This study aims to test hypotheses that are potentially important to diabetes management, with practical implications for reducing the medical, personal, and economic costs of the disease. Anticipated outcomes include reductions in glycosylated hemoglobin that are significantly greater than those achievable with current diet recommendations, reductions in medication use among many intervention-group participants, beneficial changes in body weight and serum lipid concentrations, and a demonstration of the acceptability of the intervention diet. Progress toward these goals could refine dietary guidance for individuals with diabetes, increase treatment expectations, and reduce the massive burden the disease currently imposes.

The study further attempts to translate a dietary intervention studied in a clinical research setting to a medical practice. This will contribute to developing a model for diabetes care that can be used widely.

Study Overview

• Status: Completed
• Conditions: Diabetes Mellitus, Type 2
• Intervention / Treatment: Other: Vegan diet; Other: American Diabetes Association guidelines

Detailed Description

Specific Aim 1 tests the hypothesis that the nutrition intervention (low-fat, low-GI, vegan diet; henceforth called the 'vegan diet') improves glycemic control, body weight, plasma lipid concentrations, blood pressure, and indices of renal function in a within-group analysis.

Glycosylated hemoglobin is the primary dependent variable, as well as fasting plasma glucose and urinary albumin and creatinine concentrations. The within-group changes in these variables from baseline to week 20, one-year follow-up will be compared.

Specific Aim 2 tests the hypothesis that the vegan diet is more effective than standard nutrition care for improving glycemic control, body weight, plasma lipid concentrations, blood pressure, and indices of renal function in individuals with type 2 diabetes.

Glycosylated hemoglobin is the primary dependent variable, as well as fasting plasma glucose and urinary albumin and creatinine concentrations in both the intervention and control groups. The between-groups differences in the changes in these variables from baseline to week 20, and one-year follow-up will be compared.

Specific Aim 3 tests the hypothesis that the vegan diet is sustainable among individuals with type 2 diabetes for a 20-week period, with weekly classes, and in a follow-up period of one year with limited professional support.

This will be assessed by 3-day dietary records at weeks 0, 20 and one-year follow-up.

Specific Aim 4 tests the hypothesis that the vegan diet has an acceptability that is comparable to that of standard nutrition care among individuals with type 2 diabetes.

This hypothesis will be addressed by quantitatively assessing adherence to and acceptability of the intervention and control diets, using the 3-day dietary record, the Food Acceptability Questionnaire, and the Eating Inventory, as described below.

Specific Aim 5 tests the hypothesis that the effects of the dietary interventions on A1c and body weight are reduced in individuals with the A1 and B1 alleles of the DRD2 gene.

This will be assessed through Taq1 A1 and B1 genotype determination at baseline.

• Study Type: Interventional
• Enrollment (Actual): 15
• Phase: Not Applicable

Contacts and Locations

Study Locations

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

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. a diagnosis of type 2 diabetes mellitus, as defined by a fasting plasma glucose concentration ≥126 mg/dl on 2 occasions or a prior physician's diagnosis of type 2 diabetes with the use of hypoglycemic medications for at least 6 months
2. male or female
3. A1c between 6.5% and 10.5%
4. age at least 18 years
5. ability and willingness to participate in all components of the study
6. willingness to be assigned to either a low-fat, vegan diet or to standard care
7. diabetes medications unchanged for 1 month prior to volunteering for the study
8. patient of Dr. Mark Sklar

Exclusion Criteria:

1. body mass index >45 kg/m2
2. 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
3. use of recreational drugs in the past 6 months (past drug use, if fully recovered, is not a criteria for exclusion)
4. pregnancy
5. history of severe mental illness (with current unstable status)
6. likely to be disruptive in group sessions (as determined by research staff)
7. Signs/symptoms of acute uncontrolled diabetes (including but not limited to polyuria, polydipsia, blurred vision, uncontrolled weight loss)
8. unstable medical status
9. already following a low-fat, vegetarian diet
10. an inordinate fear of blood draws
11. inability to maintain current medication regimen
12. lack of English fluency

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Vegan Group; Participants in the intervention group will follow a low-fat, vegan diet for 20 weeks, and will attend nutrition classes in the form of a weekly support group.	Other: Vegan diet; A diet devoid of any animal products. Low-fat, low-Glycemic Index, vegan diet.; Other Names: Plant-based diet
Active Comparator: American Diabetes Association guidelines; Participants will follow ADA diet according to ADA regulations. This group will also receive weekly nutrition classes.	Other: American Diabetes Association guidelines; Participants will follow individualized diet plans following ADA guidelines; Other Names: ADA

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
hemoglobin A1C (diabetes management)	20 weeks

Secondary Outcome Measures

Outcome Measure	Time Frame
Body Weight	20 Weeks
Blood Pressure	20 Weeks
Glucose	20 Weeks
Comprehensive Metabolic Panel	20 Weeks & one-year follow up
Serum cholesterol and triacylglycerol concentrations	20 Weeks
Urinary albumin and creatinine	20 Weeks
Genotyping for Taq1 A and Taq1 B polymorphisms, and APOE (Apolipoprotein E)	20 Weeks
Waist and hip circumference	20 Weeks
Dietary Acceptability	20 Weeks
3-day dietary records	20 Weeks
International Physical Activity Questionnaire	20 Weeks
Food Acceptability Questionnaire	20 Weeks
Eating Inventory	20 Weeks
CESD-R (Center for Epidemiologic Studies Depression Scale: Review and revision)	20 Weeks
Beck Depression Inventory II (BDI-II)	20 Weeks
Height	20 Weeks
24-Hour Multi-Pass Dietary Recalls	20 Weeks

Collaborators and Investigators

• Sponsor: Physicians Committee for Responsible Medicine
• Investigators: Principal Investigator: Neal Barnard, MD, Physicians Committee for Responsible Medicine

Publications and helpful links

General Publications

• Nicholson AS, Sklar M, Barnard ND, Gore S, Sullivan R, Browning S. Toward improved management of NIDDM: A randomized, controlled, pilot intervention using a lowfat, vegetarian diet. Prev Med. 1999 Aug;29(2):87-91. doi: 10.1006/pmed.1999.0529.
• Ornish D, Scherwitz LW, Billings JH, Brown SE, Gould KL, Merritt TA, Sparler S, Armstrong WT, Ports TA, Kirkeeide RL, Hogeboom C, Brand RJ. Intensive lifestyle changes for reversal of coronary heart disease. JAMA. 1998 Dec 16;280(23):2001-7. doi: 10.1001/jama.280.23.2001. Erratum In: JAMA 1999 Apr 21;281(15):1380.
• Esselstyn CB Jr. Updating a 12-year experience with arrest and reversal therapy for coronary heart disease (an overdue requiem for palliative cardiology). Am J Cardiol. 1999 Aug 1;84(3):339-41, A8. doi: 10.1016/s0002-9149(99)00290-8.

Study record dates

Study Major Dates

• Study Start: July 1, 2014
• Primary Completion (Actual): July 1, 2015
• Study Completion (Actual): July 1, 2015

Study Registration Dates

• First Submitted: October 2, 2012
• First Submitted That Met QC Criteria: October 2, 2012
• First Posted (Estimate): October 4, 2012

Study Record Updates

• Last Update Posted (Estimate): October 20, 2015
• Last Update Submitted That Met QC Criteria: October 19, 2015
• Last Verified: October 1, 2015

More Information

Terms related to this study

• Keywords: Diabetes Mellitus, Type 2; Diet, Vegetarian; Diet, Fat-Restricted; Glycemic Index
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Endocrine System Diseases; Diabetes Mellitus; Diabetes Mellitus, Type 2
• Other Study ID Numbers: PBNI-2