Fiber Supplements Derived From Sugarcane Stem, Wheat Dextrin and Psyllium Husk Have Different In Vitro Effects on the Human Gut Microbiota.

Hasinika K A H Gamage,Ian T Paulsen,Carly P Rosewarne,Mark P Molloy,Malcolm S Ball,Raymond W W Chong,Daniel Bucio-Noble,Nicolle H Packer,Liisa Kautto,Sasha G Tetu

doi:10.3389/fmicb.2018.01618

Abstract

There is growing public interest in the use of fiber supplements as a way of increasing dietary fiber intake and potentially improving the gut microbiota composition and digestive health. However, currently there is limited research into the effects of commercially available fiber supplements on the gut microbiota. Here we used an in vitro human digestive and gut microbiota model system to investigate the effect of three commercial fiber products; NutriKane™, Benefiber® and Psyllium husk (Macro) on the adult gut microbiota. The 16S rRNA gene amplicon sequencing results showed dramatic fiber-dependent changes in the gut microbiota structure and composition. Specific bacterial OTUs within the families Bacteroidaceae, Porphyromonadaceae, Ruminococcaceae, Lachnospiraceae, and Bifidobacteriaceae showed an increase in the relative abundances in the presence of one or more fiber product(s), while Enterobacteriaceae and Pseudomonadaceae showed a reduction in the relative abundances upon addition of all fiber treatments compared to the no added fiber control. Fiber-specific increases in SCFA concentrations showed correlation with the relative abundance of potential SCFA-producing gut bacteria. The chemical composition, antioxidant potential and polyphenolic content profiles of each fiber product were determined and found to be highly variable. Observed product-specific variations could be linked to differences in the chemical composition of the fiber products. The general nature of the fiber-dependent impact was relatively consistent across the individuals, which may demonstrate the potential of the products to alter the gut microbiota in a similar, and predictable direction, despite variability in the starting composition of the individual gut microbiota.

Highlights

Trillions of microorganisms reside in the human large intestine, which is collectively referred to as the gut microbiota (Cani et al, 2016)
As dietary supplementation grows in popularity it is important to examine how commercial fiber products impact the human gut microbial communities and host health, and the degree to which this varies between products
We tested the in vitro impact of three different fiber supplements using fecal microbial communities sourced from six healthy individuals

Summary

Introduction

Trillions of microorganisms reside in the human large intestine, which is collectively referred to as the gut microbiota (Cani et al, 2016). Compositional and functional alterations of the gut microbiota have been associated with various inflammatory and metabolic diseases such as obesity (Turnbaugh et al, 2009), type 2 diabetes (T2D) (Karlsson et al, 2013), type 1 diabetes (T1D) (Knip and Siljander, 2016), and inflammatory bowel disease (IBD) (Frank et al, 2007). Diet has been shown to impact the composition and activities of the gut microbiota (Conlon and Bird, 2015; Fontana and Partridge, 2015). The overall structure of the gut microbiota has been reported to respond within a day to short-term consumption of entirely animal or plant based diets (David et al, 2014). There is evidence that individual dietary preferences correlate to some degree with longer-term gut microbiota composition (Wu et al, 2011). Similar observations have been made in a number of studies that looked at different communities of people who consume diets rich in fiber in comparison to diets low in fiber (De Filippo et al, 2010; Yatsunenko et al, 2012; Lin et al, 2013; Schnorr et al, 2014; O’Keefe et al, 2015)

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