Practice Based Nutrition Intervention-2

Overview

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.

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.