Day-to-Day Consistency in Amount and Source of Carbohydrate Intake Associated with Improved Blood Glucose Control in Type 1 Diabetes

Abstract

Objective: To determine if a relationship exists between blood glucose control and variability in nutrient intake from day-to-day in subjects with type 1 diabetes.Methods: Two three-day diet records and one measurement of glycated hemoglobin (HbA1c) were obtained from 272 subjects with type 1 diabetes treated with a mixture of regular and NPH insulins before breakfast and supper and using a standardized algorithm to adjust insulin dose according to the results of self-monitoring of blood glucose two to four times daily. Day-to-day variation in nutrient intake was expressed as the coefficient of variation (CV=SD×100/mean).Results: Nutrient intakes in the study population (mean±SD) were energy 8.35±2.43 MJ, fat 81±30 g, protein 94±28 g, carbohydrate 227±68 g, starch 126±38 g and dietary fiber 20±6 g with diet glycemic index being 84.2±7.4. Neither energy, nutrient intakes nor insulin dose was significantly related to HbA1c. Day-to-day variation of carbohydrate (p=0.0097) and starch (p=0.0016) intakes and diet glycemic index (p=0.033) was positively related to HbA1c, and the associations remained significant when adjusted for age, sex, duration of diabetes and BMI. Day-to-day variation in energy, protein or fat intakes was not related to HbA1c.Conclusions: Consistency in the amount and source of carbohydrate intake from day-to-day is associated with improved blood glucose control in people with type 1 diabetes, a result which supports continued educational efforts to achieve adherence to a diabetes diet plan. This conclusion may not apply to people on intensified insulin therapy who adjust their insulin dose based on their actual carbohydrate intake at each meal.