The Effect of Two Types of Pasta Versus White Rice on Postprandial Blood Glucose Levels in Adults with Type 1 Diabetes: A Randomized Crossover Trial

Abstract

Background: Food choices are essential to successful glycemic control for people with diabetes. We compared the impact of three carbohydrate-rich meals on the postprandial glycemic response in adults with type 1 diabetes (T1D). Methods: We performed a randomized crossover study in 12 adults with T1D (age 58.7 ± 14.2 years, baseline hemoglobin A1c 7.5% ± 1.3%) comparing the postprandial glycemic response to three meals using continuous glucose monitoring: (1) "higher protein" pasta containing 10 g protein/serving, (2) regular pasta with 7 g protein/serving, and (3) extra-long grain white rice. All meals contained 42 g carbohydrate; were served with homemade tomato sauce, green salad, and balsamic dressing; and were repeated twice in random order. After their insulin bolus, subjects were observed in clinic for 5 h. Linear mixed effects models were used to assess the glycemic response. Results: Compared with white rice, peak glucose levels were significantly lower for higher protein pasta (-32.6 mg/dL; 95% CI -48.4 to -17.2; P < 0.001) and regular pasta (-43.2 mg/dL, 95% CI -58.7 to -27.7; P < 0.001). The difference between the two types of pastas did not reach statistical significance (-11 mg/dL; 95% CI -24.1 to 3.4; P = 0.17). Total glucose area under the curve was also significantly higher for white rice compared with both pastas (P < 0.001 for both comparisons). Conclusions: This exploratory study concluded that different food types of similar macronutrient content (e.g., rice and pasta) generate significantly different postprandial glycemic responses in persons with T1D. These results provide useful insights into the impact of food choices on and optimization of glucose control. Clinical Trial Registry: clinicaltrials.gov NCT03362151.

Keywords: Carbohydrate choices; Continuous glucose monitoring; Glycemic control; High protein; Nutrition; Pasta; Rice; Type 1 diabetes.

Conflict of interest statement

D.M.E. has served as a consultant to and member of a scientific advisory committee of The Culinary Institute of America and is a scientific advisor to the Health and Wellness Advisory Committee of the Barilla Center for Food & Nutrition (Italy). J.E.P. has received product support to his institution as principal investigator from Dexcom, Inc. outside of the submitted study. No competing financial interests relevant to this project are reported for the rest of the authors.

Figures

FIG. 1.

Top panel: median and IQR of CGM postprandial glucose profiles for the three meal types—higher protein pasta (A), regular pasta (B), and white rice (C). Bottom panel: the CGM profiles are corrected at baseline by subtracting the CGM value at the start of the meal at each CGM time point for each subject (D). White rice shows a higher glycemic response than the higher protein pasta or regular pasta. The meal effect (i.e., time required to return to baseline blood glucose level) decreased after ∼2 h of the meal start for both types of pasta, whereas the effect required up to 5 h to diminish for white rice. There were no significant differences between the two types of pasta. CGM, continuous glucose monitoring.

FIG. 2.

Box-and-Whisker plot of postprandial blood glucose total AUC after the meals higher protein pasta, regular pasta, and white rice. The left subplot illustrates the total AUC during the 0–3 h postprandial period, the middle subplot shows the total AUC during the late postprandial period 3–5 h, and the right subplot shows the total AUC for the entire postprandial period 0–5 h. The three asterisks indicate statistical significance with P < 0.001, whereas the one asterisk shows P < 0.05 for differences between the total AUC of the three meal types as computed from the linear mixed effect model. AUC, area under the curve.