Dietary Glycemic Index and Glycemic Load Are Associated with Metabolic Control in Type 2 Diabetes: The CAPRI Experience

Background: The role of low-glycemic-index diets in the treatment of diabetes mellitus remains unclear. The aim of the present study was to evaluate the association between the dietary glycemic index (GI) and glycemic load (GL) with metabolic control in type 2 diabetic patients. Methods: We conducted a cross-sectional analysis in 901 outpatients with type 2 diabetes attending diabetes clinics located in the area of the Campania County, South Italy, who provided complete home blood glucose profiles and centralized glycosylated hemoglobin A1c (HbA1c). Dietary information was obtained using semiquantitative food-frequency questionnaires. HbA1c was assessed in the centralized laboratory while blood glucose profiles were assessed at home. Results: After adjustment for age, body mass index (BMI), waist circumference, waist-to-hip ratio, smoking, alcohol consumption, physical activity, medication use, prevalence of metabolic syndrome, hypertension, energy and fiber intake, dietary GI and GL were positively associated with HbA1c in a dose-dependent fashion (P for trend, 0.007 for GI and 0.02 for GL). Diabetic patients with the highest GI and GL had the highest HbA1c levels (difference 1%, P = 0.001). The difference in 1-h postmeal glucose levels at home between the highest and the lowest quintile of GI was 37 (15) [mean and standard deviation (SD)] mg/dL (P = 0.001). Conclusions : Diets low in GI and GL are associated with lower HbA1c and postmeal glucose levels in the everyday life of type 2 diabetic patients.