(PTFS08-05-23) Dietary Fiber Intake and Gut Microbial Features Predict Gut Microbiota Response to Resistant Starch Consumption

Objectives: Resistant starch (RS) can have beneficial effects on human health, but the response, in terms of effects on the gut microbiota and host physiology, varies between individuals. Factors predicting the response to RS are not yet established and would be useful for developing precision nutrition approaches that maximize the benefits of dietary fiber intake. The goal of this study was to evaluate candidate predictors of gut microbiota response to RS supplementation.

Methods: We enrolled 76 healthy men and women into a seven-week crossover dietary intervention study in which they consumed RS type 2 (RS2), RS type 4 (RS4), and a control digestible starch, for 10 days each with five-day washout periods in between. We collected fecal samples, saliva samples, and food records before and during each treatment period. We performed 16S rRNA gene sequencing, fecal short-chain fatty acid (SCFA) measurements, genotyping for AMY1 gene copy number, and salivary amylase activity (SAA) measurements. For statistical analyses, we used linear mixed models, logistic regression, and LASSO regression.

Results: Dietary fiber intake and the order in which RS2 and RS4 were consumed (treatment order) were predictive of the change in relative abundance of amplicon sequence variants (ASVs), while treatment order, alpha diversity, and relative abundances of a subset of ASVs were predictive of SCFA changes after RS supplementation. SAA was only predictive of relative abundance of ASVs after digestible starch supplementation. AMY1-related metrics were not predictive of response to RS.

Conclusions: Dietary fiber intake, gut microbiota composition and treatment order are predictive of changes in relative abundance of ASVs and SCFA concentrations in response to RS and could be informative if assessed prior to recommending RS supplementation. Using a precision nutrition approach to optimize the benefits of consuming dietary fibers such as RS could be an effective strategy to compensate for the low consumption of dietary fiber nationwide.

Funding Sources: Funding sources for this work include the President’s Council of Cornell Women and a National Institutes of Health NIDDK T32 award.