Metabolic Responses to Native Wheat Starch (MidsolTM 50) versus Resistant Wheat Starch Type 4 (Fibersym® RW): Standard versus Marketplace Testing Protocols

Abstract

Background To investigate the effect of RS on acute glycemic or insulinemic responses, the FDA indicates that control and RS-enriched foods must contain equivalent amounts of digestible carbohydrate. However, RS-containing foods typically contain less digestible carbohydrate per serving than control foods. Thus, controlling for digestible carbohydrate may yield different responses as compared with controlling for serving size. Objective To compare the postprandial metabolic responses to native wheat starch (NWS) versus resistant starch type 4 (RS4) using digestible carbohydrate-matched portions compared to weight-matched portions. Methods A single-blinded randomized-controlled crossover trial examined glycemic and insulinemic responses over two hours following consumption of four cracker conditions and a dextrose beverage in apparently healthy participants (n = 14). Crackers provided 50g of digestible carbohydrate (CHO) using the FDA's meal-intervention protocol, or 35g of CHO by weight for the marketplace substitution method. Crackers differed only by the type of starch additive: NWS (MidsolTM 50) or RS4 (Fibersym® RW). Glucose levels were assessed at baseline, 15, 30, 45, 60, 90, and 120 minutes; insulin levels were measured at baseline, 30, 60, and 120 minutes. Results There were no significant differences between 50g digestible CHO cracker conditions for glucose or insulin iAUC. The 35g CHO by weight conditions were not different for glucose iAUC (Mean (95% CI); 35g NWS: 1317 (677, 2169), 35g RS4: 701 (262, 1351), p > 0.05). However, insulin iAUC was lower following 35g RS4 compared to 35g NWS (35RS4: 92 (10, 259), 35NWS: 697 (397, 1080), p < 0.01). Conclusion In healthy adults, consumption of RS4 crackers decreased postprandial insulin responses compared with NWS crackers when using the marketplace substitution method compared to the FDA standard testing method, with similar postprandial glucose responses. Comparisons of the FDA standard testing method and the marketplace substitution method should be investigated further to elucidate differential physiological impacts on consumers.

Glycemic and Insulinemic Responses of Healthy Humans to a Nutrition Bar with or without Added Fibersym® RW, a Cross-Linked Phosphorylated RS4-Type Resistant Wheat Starch

“…The current study was conducted as a single-blinded randomized-controlled crossover trial, where all participants experienced all treatments. Methods and procedures were modified from Steele et al, [ 13 ]. Specifically, the timepoints of whole blood collection and the method of glucose analysis were modified.…”

“…Existing randomized controlled trials have shown beneficial effects of RS4 intake on glycemic and insulinemic responses [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. To test the benefits of RS4 for fiber food label classification, researchers often test at a 50 g amount of digestible carbohydrate [ 8 , 13 , 19 ].…”

“…Existing randomized controlled trials have shown beneficial effects of RS4 intake on glycemic and insulinemic responses [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. To test the benefits of RS4 for fiber food label classification, researchers often test at a 50 g amount of digestible carbohydrate [ 8 , 13 , 19 ]. In a research setting, this amount of digestible carbohydrate typically requires a larger bolus of food than is typically consumed by consumers in a single sitting.…”

“…In a research setting, this amount of digestible carbohydrate typically requires a larger bolus of food than is typically consumed by consumers in a single sitting. For this reason, there may be differential responses observed at these testing amounts that may not translate to a typical, standard serving size for consumers [ 13 ]. There is limited research, using an FDA-approved testing approach for fiber food label classification, incorporating lower doses (<50 g) of digestible carbohydrate that are likely to represent more typical consumption amounts.…”

Resistant starch type-4 intake alters circulating bile acids in human subjects

“…Phosphorylated cross-linked RS4 produced from wheat starch is marketed as a dietary fiber that can be used as a stealth ingredient to swap higher-calorie starches without compromising palatability or major recipe alterations (29-31). We and others have shown that a diet supplemented with this food-ingredient may attenuate blood glucose and cholesterols, increase satiety, and lower body weight, fat, and inflammation (8,16,29,31,32). A similar RS4 product derived from maize has also demonstrated metabolic health benefits (33,34).…”