Type-4 Resistant Starch in Substitution for Available Carbohydrate Reduces Postprandial Glycemic Response and Hunger in Acute, Randomized, Double-Blind, Controlled Study

The majority of research on the physiological effects of dietary resistant starch type 2 (RS2) has focused on sources derived from high-amylose maize. In this study, we conduct a double-blind, randomized, placebo-controlled, crossover trial investigating the effects of RS2 from wheat on glycemic response, an important indicator of metabolic health, and the gut microbiota. Overall, consumption of RS2-enriched wheat rolls for one week resulted in reduced postprandial glucose and insulin responses relative to conventional wheat when participants were provided with a standard breakfast meal containing the respective treatment rolls (RS2-enriched or conventional wheat). This was accompanied by an increase in the proportions of bacterial taxa Ruminococcus and Gemmiger in the fecal contents, reflecting the composition in the distal intestine. Additionally, fasting breath hydrogen and methane were increased during RS2-enriched wheat consumption. However, although changes in fecal short-chain fatty acid (SCFA) concentrations were not significant between control and RS-enriched wheat roll consumption, butyrate and total SCFAs were positively correlated with relative abundance of Faecalibacterium, Ruminoccocus, Roseburia, and Barnesiellaceae. These effects show that RS2-enriched wheat consumption results in a reduction in postprandial glycemia, altered gut microbial composition, and increased fermentation activity relative to wild-type wheat.

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Effect Modification by the Gut Microbiota on Metabolic Response to Resistant Starch (RS) Wheat Supplementation (FS11-03-19)

Current Developments in Nutrition ◽

10.1093/cdn/nzz037.fs11-03-19 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

Author(s):

Riley Hughes ◽

Maria Marco ◽

Mary Kable ◽

Nancy Keim

Keyword(s):

Gut Microbiota ◽

Resistant Starch ◽

Metabolic Response ◽

Individual Variability ◽

Rrna Gene ◽

Glycemic Response ◽

Breath Hydrogen ◽

Trial Duration ◽

Double Blind ◽

Total Dietary Fiber

Abstract Objectives The objective of the study is to determine whether features of individuals’ baseline gut microbiota modify the effect of a resistant starch (RS) intervention on post-prandial glycemic response and other metabolic markers that have been linked to gut microbial action (i.e., short-chain fatty acids (SCFA), bile acids, breath hydrogen/methane). Methods Metabolic responses and 16S rRNA gene data generated from a double-blind, placebo controlled, crossover clinical trial of RS and regular wheat will be used to investigate whether baseline features of the microbiota are correlated with inter-individual differences in the effect of RS supplementation in individuals. Women and men consumed 3 or 4 rolls per day, respectively, made from RS (14–18 g total dietary fiber, TDF) or conventional wheat (4–5.5 g TDF) for 7 days during each arm of the trial duration. Linear mixed models of glycemic response and features of the gut microbiota hypothesized to modify the effect of the intervention as well as covariates (e.g., gender, habitual fiber intake) will be used to determine microbiota features associated with improvement in glycemic response as a result of RS supplementation. Results A total of 30 healthy adults ages 40–65 will be studied and 25 have completed the study thus far. Of the metabolic variables analyzed to date, a significant amount of inter-individual variability in the magnitude and direction of postprandial glycemia and breath hydrogen responses to RS wheat supplementation. For example, the intra-class correlations (ICC) of post-prandial glucose and insulin area under the curve (AUC) were high, 42.07% and 52.86%, respectively. However, there was a significant overall effect of RS wheat on glycemic response such that postprandial insulin during RS supplementation was lower than during regular wheat consumption (P = 0.004). Conclusions The results of this study show a high degree of inter-individual variability in metabolic response to fiber (RS) supplementation, suggesting the presence of individual factors that modify the effect of the intervention. Future studies should incorporate this analysis into their statistical plan to validate these findings and contribute to the current literature on personalized nutrition and the gut microbiota. This will enable us to predict and potentially modify metabolic response to dietary components. Funding Sources Institute for Innovation and Health (IIFH) and Arcadia Biosciences. Supporting Tables, Images and/or Graphs

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Effect of Resistant Starch (RS) Wheat Supplementation on Satiety

Current Developments in Nutrition ◽

10.1093/cdn/nzaa045_036 ◽

2020 ◽

Vol 4 (Supplement_2) ◽

pp. 403-403

Author(s):

Riley Hughes ◽

Leslie Woodhouse ◽

Nancy Keim

Keyword(s):

Resistant Starch ◽

Peptide Yy ◽

Area Under The Curve ◽

Biological Indicators ◽

Postprandial Glucose ◽

Glycemic Response ◽

Subjective Measures ◽

Double Blind ◽

Total Dietary Fiber ◽

Wheat Products

Abstract Objectives The objective of this analysis is to determine whether intake of wheat products high in resistant starch (RS) increase satiety relative to conventional wheat products via blunting of the glycemic response and stimulation of hormones such as glucose-dependent insulinotropic polypeptide (GIP), peptide YY (PYY), glucagon-like peptide-1 (GLP-1), leptin, or ghrelin. Methods Metabolic responses generated from a double-blind, placebo controlled, crossover clinical trial of RS and regular wheat were used to investigate whether RS supplementation affects subjective and objective measures of satiety relative to conventional wheat. Women and men consumed 3 or 4 rolls per day, respectively, made from RS (14–18 g total dietary fiber, TDF) or conventional wheat (4–5.5 g TDF) for 7 days during each arm of the trial. Linear mixed models of glycemic and satiety outcomes were used to determine the effect RS supplementation. Results A total of 30 healthy adults ages 40–65 completed the study. We observed a significant effect of RS wheat on glycemic response such that postprandial glucose and insulin incremental area under the curve (iAUC) during RS supplementation were lower than during regular wheat consumption (P = 0.004, P < 0.001, respectively). Biological indicators of satiety showed lower iAUC and peak GIP (piAUC < 0.001, ppeak < 0.001) as well as higher fasting and peak PYY (pfasting = 0.004, ppeak = 0.004). There were no significant effects of treatment observed for ghrelin, leptin, or GLP-1. Additionally, there were no significant effects of treatment on subjective measures of fullness or hunger during test days (P = 0.57 and P = 0.20, respectively). Conclusions The results of this analysis indicate that RS supplementation is effective at blunting the postprandial glycemic response but has marginal effects on objective and subjective measures of satiety. Further research is needed to determine the potential effects of providing RS in different doses, volumes (e.g., supplement versus whole food), food matrix (e.g., pasta versus rolls), or duration of exposure on satiety. Funding Sources Funding was provided by the University of California Innovation Institute for Food and Health with gifts from Arcadia Biosciences and Ardent Mills.

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