Munching microbes: diet–microbiome interactions shape gut health and cancer outcomes

Abstract

The gut microbiome describes the complex community of microorganisms that populate the gastrointestinal tract. Gut microbes in the large bowel utilise both dietary-derived nutrients, such as host-indigestible carbohydrates (fibre) and excess protein, host-derived nutrients (intestinal mucin), and also interact with the by-products of digestion such as bile acids. They transform these compounds into a series of metabolites that can profoundly shape host physiology both locally and systemically. These metabolites can fundamentally alter host outcomes, promoting either gut health, or sub-optimal conditions in the gut that contribute to poor health, including increased risk of cancer. The microbiome of an individual has also been shown to impact response to cancer treatment strategies, including both treatment efficacy and side-effects in the gut and more systemically. This makes the microbiome a powerful potential tool for therapeutic purposes, once we overcome the challenges associated with individual variation in microbial community composition. As the gut microbial ecosystem is primarily altered by nutrient availability, diet therefore represents an important asset in therapeutically altering the gut microbiome.