Prebiotics and Synbiotics: Dietary Strategies for Improving Gut Health

Janina A. Krumbeck; Maria X. Maldonado-Gomez; Amanda E. Ramer-Tait; Robert W. Hutkins

Disclosures

Curr Opin Gastroenterol. 2016;32(2):110-119. 

In This Article

Abstract and Introduction

Abstract

Purpose of review A wide range of dietary carbohydrates, including prebiotic food ingredients, fermentable fibers, and milk oligosaccharides, are able to produce significant changes in the intestinal microbiota. These shifts in the microbial community are often characterized by increased levels of bifidobacteria and lactobacilli. More recent studies have revealed that species of Faecalibacterium, Akkermansia, and other less well studied members may also be enriched. We review the implications of these recent studies on future design of prebiotics and synbiotics to promote gastrointestinal health.

Recent findings Investigations assessing the clinical outcomes associated with dietary modification of the gut microbiota have shown systemic as well as specific health benefits. Both prebiotic oligosaccharides comprised of a linear arrangement of simple sugars, as well as fiber-rich foods containing complex carbohydrates, have been used in these trials. However, individual variability and nonresponding study participants can make the outcome of dietary interventions less predictable. In contrast, synergistic synbiotics containing prebiotics that specifically stimulate a cognate probiotic provide additional options for personalized gut therapies.

Summary This review describes recent research on how prebiotics and fermentable fibers can influence the gut microbiota and result in improvements to human health.

Introduction

Despite the considerable research attention recently devoted to diet and microbiota, the notion that dietary components can influence gastrointestinal microbiota composition and enhance host health is not new. Indeed, this very hypothesis was envisioned more than a century ago, long before any specific foods or food constituents had been identified and before techniques for assessing microbiota complexity could be appreciated.[1,2] One of the first specific dietary components to be recognized for its unique impact on the gut microbiota was breast milk.[3] Eventually, the prebiotic concept was introduced to describe those food ingredients or constituents that enrich for beneficial organisms in the gastrointestinal tract (GIT).[4] In the past two decades, appreciable experimental and clinical evidence has emerged suggesting that prebiotics may promote gastroenterological homeostasis and/or redress specific disease states associated with microbial imbalance (i.e., dysbiosis).[5]

Like prebiotics, probiotics have also long been used as therapeutic agents for improving gastrointestinal health. However, most probiotic microorganisms are allochthonous to the intestinal environment and are generally unable to colonize or persist in the GIT.[6,7] Prebiotics have a decided advantage by enriching for organisms already present in the gut ecosystem (so-called autochthonous members). Fermentation of prebiotic carbohydrates yields butyrate and other short chain fatty acids, as well as other end products that lower the local pH, stimulate mucin production by colonocytes, and induce production of immunomodulatory cytokines.[8] Thus, prebiotics not only cause shifts in the microbiota by supporting growth of particular GIT members but also serve as substrates for production of biologically active metabolites.

Prebiotics now provide food formulators, as well as clinicians, with rather simple diet-based opportunities to influence the composition of the gut microbiota and improve intestinal health. In this review, we describe current strategies for how prebiotic approaches can be used to achieve these goals. Specifically, we address the prebiotic activity of fiber-rich foods, why some individuals respond to prebiotics and others do not, and the advantages of rational or synergistic synbiotics for inducing beneficial shifts in the gastrointestinal microbiota.

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