The Comparative Effects of White Potato and White Rice Consumption on Measures of Cardiometabolic Health in Individuals with Type 2 Diabetes Mellitus and Features of Metabolic Syndrome.

Background: The objective of this study was to compare the effects of daily consumption of white potatoes compared with white rice on cardiometabolic health in individuals with type-2 diabetes (T2D).

Objective: To determine the effects of white potato consumption compared to white rice (a commonly consumed refined grain) on indices of glycemic control and cardiovascular health in individuals with overweight or obesity and T2D.

Methods: In this randomized crossover study, comparative control trial, 24 adults with T2D [45-80 y, body mass index (kg/m) 25-40] consumed baked white potatoes (100 g) or calorie-matched white rice (75 g) daily for 12 wk, separated by a 2-wk washout, with assessments of glycemic control, lipids, inflammation, blood pressure, endothelial function, and body composition at baseline (only 1 baseline visit included as a covariate in statistical analyses), 6 wk, and 12 wk. A linear mixed model was used to assess treatment (potato or rice), time (6 wk or 12 wk), and the treatment-by-time interaction for all outcome variables.

Results: There were no significant ( ≤ 0.05) treatment-by-time interactions for any outcome. There was a main effect of treatment (i.e., independent of time) with the potato regimen resulting in lower waist circumference ( < 0.0001; 4.5 ± 1.0 cm), percent fat mass ( = 0.01; 1.7 ± 0.7%), waist-to-hip ratio ( = 0.002; 0.025 ± 0.013), heart rate ( = 0.01; 3.1 ± 1.2 bpm), as well as higher percent fat-free mass ( = 0.05; 1.4 ± 0.7%) and maximum brachial artery dilation ( = 0.05; 0.074 ± 0.037 mm) when compared to the rice regimen. There were significant timepoint effects (i.e., independent of treatment) for increased homeostatic model assessment of β-cell function ( = 0.02; 34.3 ± 14.5) and decreased high sensitivity C-reactive protein ( = 0.02; 0.08 ± 0.05 g/mL) and flow-mediated dilation/shear ( = 0.03; 4.3 × 10 ± 3.79 × 10) during the study.

Conclusions: White potatoes did not negatively affect glycemic indices, vascular health, lipids, or blood pressure compared to white rice and modestly improved body composition and vascular measures. In both groups, over time, there were reductions in flow-mediated dilation/shear stress, β cell function, and high-sensitivity C-reactive protein. Our preliminary results support white potatoes as a substitute for white rice in T2D.