Because degree of diabetes complications is directly linked to level of diabetes control, current diabetes regimens are placing increasing emphasis on maintenance of near-normal glycemia through the use of more intensive insulin regimens and carbohydrate counting. While moderation in the use of simple sugar is recommended, the source or quality of carbohydrate is not currently considered an integral part of the regimen. However, a growing body of evidence indicates that carbohydrates with a lower glycemic index may reduce postprandial hyperglycemia and improve overall glycemic control. Such a diet would consist of greater consumption of carbohydrate from nutrient-dense whole foods - whole grains, fruits, vegetables, and legumes - in accordance with the HHS-USDA 2005 Dietary Guidelines for Americans. Two pilot studies have provided data to guide the development of this program of research. A pilot study was conducted during the summer of 2004 to investigate the feasibility and acceptability of implementing a low glycemic index diet in the diabetes camp setting. Camp provides an ideal setting to introduce youth to a lower glycemic index diet, because exposure to foods is controlled, and a sufficient number of meals are served to assess acceptability across a range of foods. Youth ages 7 to 15 attending a diabetes summer camp were served standard diabetes camp menus and lower glycemic index diabetes camp menus in a daily alternating cross-over design. Measures of satisfaction with the camp meals and snacks were obtained from youth and staff, and observations of meal consumption were conducted. Additional data were collected via focus groups, and self-report of food patterns and preferences. Meal plans and blood glucose monitoring data were obtained from camp records. A pilot study was conducted during the summer of 2006 testing blood glucose response to low and high glycemic index meals in youth with diabetes using continuous blood glucose monitoring. In this study, youth with diabetes participated in 5 days of continuous blood glucose monitoring during which they received both low and high glycemic index meals both in a structured clinic setting and in the home environment. Food intake, insulin, and blood glucose self-monitoring were recorded. Analyses are in progress, and include comparison of mean blood glucose, excursions, and variability. A series of focus groups addressed perceptions of healthful eating among families of children with type 1 diabetes to guide development of a behavioral intervention to be testing in the upcoming efficacy trial. The focus groups were conducted separately with children, adolescents, and parents. In addition, a cross-sectional observational study assessing potential modifiable factors associated with dietary intake was conducted. Data collected include child and parent dietary intake, family eating patterns, food availability, nutrition knowledge, parent and child beliefs regarding healthful eating (e.g., barriers, outcome expectations, self-efficacy), and parent and peer modeling of healthful eating. An efficacy trial of a behavioral intervention designed to increase consumption of carbohydrates from lower glycemic, nutrient dense, whole food sources is underway. The purpose of this trial is to determine the efficacy of a behavioral nutrition intervention for children with type 1 diabetes ages 8 to 16 and their families. The goal of the intervention is to increase the consumption of carbohydrates from low glycemic index, nutrient-dense whole foods (i.e., fruits, vegetables, whole grains, legumes). The effect of the dietary intervention on glycemic control and other diabetes-specific outcomes (e.g., glycemic excursions, insulin dose and frequency of hypoglycemia), body composition, lipid profiles, oxidative stress and inflammation will be determined. In addition, effects of the intervention on psychosocial factors (e.g., quality of life and disordered eating behaviors) will be investigated. A total of 160 families will be randomly assigned to either a behavioral nutrition intervention or a control condition. Participants in both groups will use episodic masked continuous glucose monitoring (CGM) at predetermined intervals during the study. Participants in the control condition will receive usual diabetes care, including general diabetes-related education promoting a healthy lifestyle. Participants in the behavioral nutrition intervention will participate in a series of group-based and family-based sessions during the first 12 months of the study. These sessions will use behavioral techniques and educational content to promote increased consumption of carbohydrates from low glycemic index, nutrient-dense whole foods, and decreased consumption of highly processed carbohydrate-containing foods. Additional booster contacts will occur for the following 6 months of the study. Dietary intake, social and cognitive mediators, and health outcomes will be assessed at baseline, 6 months, 12 months, and 18 months. Primary outcomes will be dietary quality and hemoglobin A1c, an established measure of long-term glycemic control. It is anticipated that this research will provide data that are critical for guiding dietary guidelines for persons with diabetes. Findings will advance understanding of: 1) the efficacy of behavioral interventions for youth with diabetes designed to increase consumption of whole grains, fruits, vegetables, and legumes;2) mediators and moderators of behavior change;and 3) physiological effects of dietary change. Dietary recommendations for persons with diabetes must take into account both the potential benefits dietary change, as well as the feasibility, acceptability, and expected difficulty of implementing such recommendations. Studies to date have relied primarily on either experimental manipulation or traditional dietary education to achieve dietary change, and so provide little information to guide clinical practice with free-living individuals. Thus, findings from this study will address areas that are currently lacking in the knowledge base.
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