Location: Immunity and Disease Prevention ResearchTitle: Resistant starch type 2 from wheat reduces postprandial glycemic response with concurrent alterations in gut microbiota composition
|HUGHES, RILEY - University Of California, Davis
|FINNEGAN, PETER - University Of California, Davis
|MARCO, MARIA - University Of California, Davis
Submitted to: Nutrients
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2021
Publication Date: 2/17/2021
Citation: Hughes, R.L., Horn, W.F., Finnegan, P., Newman, J.W., Marco, M.L., Keim, N.L., Kable, M.E. 2021. Resistant starch type 2 from wheat reduces postprandial glycemic response with concurrent alterations in gut microbiota composition. Nutrients. 13(2):645. https://doi.org/10.3390/nu13020645.
Interpretive Summary: Resistant starch type 2 (RS2) is a kind of carbohydrate that is not digestible by human enzymes and therefore passes through the digestive tract to the colon where it is fermented by the bacteria residing there. Similar to other dietary fibers, RS2 may have a positive influence on glycemic response. RS2 enriched wheat is now available. Therefore, we asked 30 healthy males and females, aged 40-65 years to sequentially consume roll products made of RS2-enriched wheat or wild-type wheat for eight days each. On the eighth day subjects were asked to consume a test meal containing either RS2-enriched wheat or wild-type wheat. Glucose and insulin responses measured immediately following consumption of the meal were reduced in the RS2 intervention group relative to control. We also found that the gut bacterial community structure was shifted and measures of microbial fermentation, including breath hydrogen and stool pH indicated increased fermentation when individuals consumed RS2-enriched rolls. Short chain fatty acid (SCFA) production was associated with both glucose response and the relative abundance of certain types of bacteria, suggesting that the relative proportion of certain bacteria in the gut can influence the health benefit received by an individual during consumption of RS2-enriched wheat rolls.
Technical Abstract: 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, RS2-enriched wheat provided in a standard breakfast meal resulted in reduced postprandial glucose and insulin responses relative to conventional wheat. This was accompanied by an increase in the proportions of bacterial taxa Ruminococcus and Gemmiger. Additionally, although changes in SCFA production were not significant between control and RS-enriched wheat roll consumption, SCFAs were correlated with both glycemic response and relative abundance of Faecalibacterium, Ruminoccocus, Roseburia, and Barnesiellaceae. These effects suggest that RS2-enriched wheat may improve metabolic indices and reduce risk of metabolic disease compared to regular wheat and that the gut microbiome may play a role in mediating the individual’s metabolic response.