Diet-microbe interactions in the gut: effects on human health and disease

State of the art post genomics studies are highlighting the important role played by our resident intestinal microbiota in determining human health and disease. Many chronic human diseases associated with modern lifestyles and diets, including those localised to the intestinal tract like inflammatory bowel disease and celiac disease, and more pervasive systemic conditions such as obesity, diabetes and cardiovascular disease are characterised by aberrant profiles of gut bacteria or their metabolites. Many of these diseases have an inflammatory basis, often presenting with a chronic low-grade systemic inflammation, hinting at persistent and inappropriate activation of inflammatory pathways. Recent nutrition studies are providing novel insight into the possible mechanisms underpinning the disease processes associated with these pathologies, with high fat diets appearing to predispose to disease, and biologically active plant components, mainly fiber and polyphenols, appearing to reduce the risk of chronic disease development. Importantly, many of these plant food bioactives appear to work through the human gut microbiota. The picture that is emerging is that many of the chronic diseases associated with modern living may have an underlying aetiology linked to deviation from traditional human diets rich in whole plant foods, down regulation of our closely co-evolved gut microbiota, reduced exposure to environmental/food microorganisms and resultant dysregulation of immunological defences, in particular, disruption of the intestinal barrier and compromised immune homeostasis. Drawing on expert opinions from the fields of nutrition, gut microbiology, mammalian physiology, food science and immunology, this book presents the evidence for a unified disease mechanism working through the gut and its resident microbiota and linking many inflammation related chronic diet associated diseases.