Anne Peters, MD, and Lori Laffel, MD, MPH, Editors
Jane Lee Chiang, MD, Managing Editor
Marion J. Franz, MS, RD, CDE; Alison B. Evert, MS, RD, CDE; Gail Spiegel, MS, RD, CDE; Carol Brunzell, RD, CDE; Joyce Green Pastors, MS, RD, CDE; Joshua J. Neumiller, PharmD, CDE, CGP, FASCP; Laurie A. Higgins, MS, RD, LDN, CDE; and Mary Ziotas Zacharatos, RD, CDE, LD
Healthy nutrition is critically important in the management of individuals with type 1 diabetes (T1D). Historically, the diet for T1D patients restricted higher carbohydrate meals and discouraged snacks and desserts. In recent decades, greater understanding of physiology has enabled liberalization of the diet. The advent of multiple daily insulin injections and insulin pump therapy has allowed greater freedom in food choices and timing. However, this has required that T1D individuals become ever more sophisticated about carbohydrate counting and dosing insulin for anticipated food consumption as well as dosing if additional carbohydrates are consumed.
This chapter is not meant to discuss general nutrition principles or weight-loss approaches. Rather, it is meant to review very specific issues related to nutrition and T1D management. General nutrition principles apply, but the goal is to address specific T1D concerns. Since nutrition issues are similar between the pediatric and adult populations, all points will apply to both groups. Specific differences will be noted.
STANDARDS OF CARE
The goals of Medical Nutrition Therapy (MNT) established by the American Diabetes Association (ADA) are:1,2
- Attain and maintain:
- Optimal blood glucose levels
- A lipid profile that reduces macrovascular disease risk
- Blood pressure levels that reduce the risk of vascular disease.
- Prevent and treat chronic diabetes complications by modifying nutrient intake and lifestyle.
- Address individual nutritional needs taking into account personal and cultural preference and willingness to change.
- Maintain the pleasure of eating by only limiting the foods when indicated by scientific evidence.
Attaining these goals necessitates continual evaluation to ensure they address age-specific and developmental requirements. Providers need to create a unique nutrition therapy plan for each patient that takes the patient’s eating preferences, behavior, and life stage into account as well as each patient’s ability to implement and follow the nutrition therapy.
Achieving these goals requires synchronizing food, insulin dosage, and activity. For example, it is difficult to improve the effectiveness of an insulin-to- carbohydrate ratio (I:C) if patients with T1D do not accurately count carbohydrates or follow an outdated food plan. T1D patients benefit from regular nutritional assessment and education. Patients reap significant benefits in overall health when nutrition is incorporated in their annual diabetes goals. Very young children, who have frequently changing caloric requirements, and the elderly, who may have changing medical needs, often benefit from more frequent, quarterly nutrition assessments and follow-up. T1D patients with concurrent medical issues (e.g., celiac disease) may require frequent and ongoing nutrition support.
EVIDENCE TO SUPPORT BENEFITS OF MEDICAL NUTRITION THERAPY
MNT studies in T1D patients are difficult to perform. Shorter studies, in controlled settings, provide a limited understanding of the true impact of nutritional interventions. Longer-term, outpatient studies give insight into dietary practices in the real world, but much of the control over the content of the diet and insulin administration is lost. Still, a number of clinical trials have been performed in people with T1D. A summary of the results is presented in Table 10.1.