High Dietary Glycemic Index and Low Fiber Content Are Associated with Metabolic Syndrome in Patients with Type 2 Diabetes

Objective: To investigate possible associations of dietary glycemic index (GI) and fiber content with metabolic syndrome (MetS) in patients with type 2 diabetes. Methods: In this cross-sectional study, 175 outpatients with type 2 diabetes (aged 61.1 +/- 9.7 years; HbA(1c) 7.3% +/- 1.4%; diabetes duration of 11 years [range, 5-17]) had food intake assessed by 3-day weighed-diet records. Dietary GI (according to FAO/WHO) and fiber content were categorized as high or low based on median values. MetS was defined according to the 2009 Joint Interim Statement. Results: Patients with MetS (n = 109) had higher 24-hour GI (60.0% +/- 6.3% vs 57.5% +/- 6.4%), higher breakfast GI (59.8% +/- 8.0% vs 55.0% +/- 9.9%), and lower fiber intake at 24 hours (17.0 +/- 6.6 g vs 21.2 +/- 8.0 g), breakfast (1.9 [1.2-3.2] vs 3.1 [1.8-4.9] g), lunch (6.2 [3.9-8.0] vs 7.5 [4.7-9.4] g), and dinner (3.3 [2.1-5.2] vs 4.9 [3.1-6.4] g; p < 0.05 for all comparisons) than patients without MetS. In multivariate analyses, high GI (similar to 60%) of 24 hours (odds ratio [OR], 2.12; 95% confidence interval [CI], 1.10-4.11; p = 0.025), breakfast (OR, 2.20; 95% CI, 1.15-4.21; p = 0.017), and lunch (OR, 2.46; 95% CI, 1.28-4.74; p = 0.007) was associated with MetS. Breakfast (OR, 2.14; 95% CI, 1.04-4.41; p = 0.039) and dinner (OR, 2.27; 95% CI, 1.15-4.49; p = 0.019) with low fiber content were also associated with MetS. When high GI and low fiber intake were combined into the same variable, associations with MetS were maintained. Conclusions: Increased dietary GI and reduced fiber content were positively associated with MetS, mainly due to breakfast intake, in patients with type 2 diabetes.