Shaping the human microbiome with prebiotic foods: current perspectives for continued development

The human gut microbiome is now seen as an important and modifiable contributor to host health. Recent post-genomic studies have highlighted the fact that an aberrant gut microbiota is a characteristic of many disease states, both chronic diseases of the gut (e.g., inflammatory bowel disease and colon cancer) and more systemic diseases (e.g., allergy, diabetes and obesity). Conversely, certain functional foods which mediate their physiological activities through the gut microbiota, have shown promise in reducing the risk of developing these diseases. Prebiotics are non-digestible food components which through modulation of the gut microbiota, mediate improved host health. They have a proven track record in modulating the gut microbiome, with numerous studies showing that they can reproducibly increase relative numbers of intestinal Bifidobacterium spp. and are emerging as a particular set of functional foods with strong scientific support for their health promoting capabilities. The bifidobacteria are a group of bacteria increasingly recognised as an indicator or biomarker of gut health. In 2010 we reviewed the various methods for selecting and testing of prebiotic functional foods and went on to discuss the challenges facing both the probiotics and prebiotics field within a market increasingly governed by the need to prove cause and effect for functional food health claims. In this 2014 update, we further discuss the implications of recent human studies which expand the prebiotic concept beyond their traditional core of non-digestible carbohydrates, to include various plant food derived polyphenols and certain whole plant foods, raising the intriguing possibility that the prebiotic concept goes far beyond fiber based functional ingredients and infact represents an inherent physiological function of whole plant foods. Prebiotics therefore may thus be considered a functional essence of plant foods already recognised for their health effects, but in a form which may be readily supplemented into the mass produced foods which make up the major part of our diet in developed economies.