Substitution of Corn Starch with Resistant Starch Type 4 in a Breakfast Bar Decreases Postprandial Glucose and Insulin Responses: A Randomized, Controlled, Crossover Study

Abstract

Background: Resistant starches type 4 (RS4) are chemically modified starches that are resistant to digestion by human enzymes.

Objective: We aimed to test our hypothesis that replacement of standard starch with RS4 in a baked breakfast bar would decrease postprandial glycemic and insulinemic responses in healthy adults.

Methods: In this double-blind, randomized crossover study, 21 healthy adults [10 men; 20-45 y old; BMI (kg/m²): 19.3-27.0] consumed a baked breakfast bar containing tapioca-based RS4 (Actistar 75330; Cargill, Inc.) or a macronutrient-matched control bar, delivering 32 g and 4 g of dietary fiber, respectively. Primary outcome was the incremental area under the curve (iAUC_{0-120 min}) for postprandial capillary glucose. Other outcomes included postprandial serum insulin iAUC_{0-120 min}, glucose and insulin maximum concentration (C_max), and time to C_max (T_max).

Results: Median glucose iAUC_{0-120 min} was 22% lower (P < 0.05) and median insulin iAUC_{0-120 min} was 37% lower (P < 0.05) after consumption of the RS4 food compared with the control food. Glucose and insulin C_max and T_max were not significantly different (P > 0.05) between foods.

Conclusion: The results suggest that replacement of standard starch with tapioca-based RS4 is a practical approach for reducing available carbohydrate in products and achieving postprandial blood glucose management. This trial was registered at clinicaltrials.gov as NCT03239288.

Keywords: Actistar; clinical trial; fiber; human; resistant starch; tapioca.

FIGURE 1

CONSORT diagram indicating sample sizes at each stage during the study. CONSORT, Consolidated Standards of Reporting Trials; ITT, intent to treat; PP, per protocol.

FIGURE 2

Capillary glucose (A) and serum insulin (B) concentrations in healthy adults (n = 21) who consumed a breakfast bar containing RS4 or a control bar that was matched for fat, protein, and total carbohydrate content, delivering 32 g and 4 g of dietary fiber, respectively. RS4, resistant starch type 4.