Resistant starch type 2 from wheat improves glycemic response with concurrent alterations in gut microbiota composition

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 Faecalibacterium, Ruminococcus, Bifidobacterium, and Roseburia. Additionally, Faecalibacterium, Ruminoccocus, Roseburia, and Barnesiellaceae were correlated with enrichment of butyrate and SCFAs, which were in turn correlated with glycemic response. 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.