Principal investigator: Tonja R. Nansel, Ph.D.
Because the degree of diabetes complications is directly linked to the level of diabetes control, current diabetes regimens are placing increased 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 whole foods, such as whole grains, fruits, vegetables, and legumes, in accordance with the HHS-USDA 2005 Dietary Guidelines for Americans.

This study, which is in the planning phase, will test an innovative program of interventions designed to promote consumption of lower glycemic carbohydrates from nutrient-dense whole foods, and to determine the efficacy of such a dietary change in promoting improved glycemic control and health outcomes among children and adolescents with type 1 diabetes. Objectives include the assessment of the:

• Efficacy of behavioral intervention in promoting long-term change in dietary practices and social and cognitive mediators of dietary practices;
• Feasibility of increasing consumption of fruits, vegetables, whole grains, and legumes among free-living youth with diabetes; and
• Short- and long-term efficacy of these dietary practices in promoting improved glycemic control and other indicators of health status.

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 because a sufficient number of meals are served to assess acceptability across a range of foods. Youth ages 7 to 15 who attended a diabetes summer camp received 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 second pilot study was conducted during the summer of 2006 to test 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 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.

It is anticipated that this research will provide data that are critical for guiding dietary regimens for persons with diabetes. Findings will advance understanding of the: 1) 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 the potential benefits of a lower glycemic index diet, 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; as a result, these efforts 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.

DESPR Collaborators

· Denise L. Haynie, Ph.D., M.P.H.
· Alisha J. Rovner, Ph.D.

Selected Publications

Nansel TR, Gellar L, & McGill A. (2008). Effect of varying glycemic index meals on blood glucose control assessed with continuous glucose monitoring in youth with type 1 diabetes on basal-bolus insulin regimens. Diabetes Care, 31(4): 695-697. PMC2367100 [Abstract]

Gellar L, Schrader K. & Nansel TR. (2007). Healthy eating practices: perceptions, facilitators, and barriers among youth with diabetes. Diabetes Educator, 33(4), 671-679. PMC2365730 [Abstract]

Nansel TR, Gellar L & Zeitzoff L. (2006). Acceptability of lower glycemic index foods in the diabetes camp setting. Journal of Nutrition Education and Behavior, 38(3):143-150. PMC2367101 [Abstract]