Resistant potato starches (type 4 RS) exhibit varying effects on laxation with and without phylum level changes in microbiota: A randomised trial in young adults

The effects of resistant potato starches on gastrointestinal (GI) function and microbiota in healthy individuals were investigated. In a 6-week, double-blind, cross-over study, subjects (N = 57; 21M; 36F) were randomised to consume 30 g fibre/d from one of three chemically modified potato starches (RS4-A, soluble, viscous; RS4-B, soluble, non-viscous; RS4-C, insoluble, non-viscous) and control in beverages for 2 weeks with a 1-week washout and daily reporting of stool frequency, Bristol Stool Form Scale (BSFS), GI symptoms and compliance. Faecal microbiota was analysed by qPCR and 16S rRNA sequencing. Stool frequency and BSFS increased only with RS4-B (P < 0.01). GI symptoms were minimal with slight increases in flatulence with all interventions (P < 0.001). There were no changes in Lactobacillus or Bifidobacteria spp. However, RS4-B decreased Firmicutes (P = 0.02) and the ratio of Firmicutes to Bacteroidetes (P = 0.01). Resistant potato starches vary in their effects on GI function, which may be related to shifts in intestinal microbiota. (C) 2016 Elsevier Ltd. All rights reserved.