Optimizing glycemic variability in type 2 diabetes using simple dietary and culinary recommendations to modulate starch digestibility: a randomized controlled trial.

Background: In type 2 diabetes (T2D), postprandial glycemic excursions significantly contribute to glycemic variability (GV) and cardiovascular risk. As starch is the main carbohydrate source controlling its digestibility in the daily diet to promote a gradual glucose release, represents a promising nutritional strategy to reduce GV and improve glycemic control.

Objective: We investigated the feasibility and efficiency of a 3-month dietary intervention emphasizing Slowly Digestible Starch (SDS) through commercial starchy product supply and dietary and culinary counseling, on GV, glycemic control and cardiometabolic profile in patients with T2D with suboptimal control.

Methods: In a randomized, parallel, single-blind, controlled trial, 51 patients with T2D completed a 12-week high-SDS (H-SDS) or low-SDS (L-SDS) diet. Participants received commercial starchy products either high or low in SDS content, with specific dietary/culinary counseling. MAGE (Mean Amplitude of Glycemic Excursions) and other intra- and inter-day GV parameters were assessed by CGMS (Continuous Glucose Monitoring System), as well as glycemic control and cardiometabolic parameters.

Results: Compared to the L-SDS diet, the H-SDS diet significantly lowered MAGE over 12 weeks (β = 30.4 [95% CI: 12.4 to 48.5]; p = 0.0025) and other intra and inter-day GV parameters (standard deviation, coefficient of variation, CONGAs (Continuous Overall Net Glycemic Action), MODD (Mean of Daily Differences) with 96% compliance throughout the study. HbA1c decreased in both groups, with a trend toward a greater reduction in the H-SDS group (β = 0.3 [95% CI: 0.05 to 0.47]; p = 0.0981]), where HbA1c fall below the 7% target. Other cardiometabolic markers were similar between diets.

Conclusions: Modulating starch digestibility represents an effective and accessible strategy for enhancing GV and thus glycemic management in T2D, allowing patients with suboptimal glycemic control to reach recommended glycemic targets. This trial was registered at ClinicalTrials.gov (identifier: NCT03847701; registered on February 18, 2019): https://clinicaltrials.gov/study/NCT03847701.