Metabolic phenotyping for understanding the gut microbiome and host metabolic interplay

There is growing interest in the role of the gut microbiome in human health and disease. This unique complex ecosystem has been implicated in many health conditions, including intestinal disorders, inflammatory skin diseases and metabolic syndrome. However, there is still much to learn regarding its capacity to affect host health. Many gut microbiome research studies focus on compositional analysis to better understand the causal relationships between microbial communities and disease phenotypes. Yet, microbial diversity and complexity is such that community structure alone does not provide full understanding of microbial function. Metabolic phenotyping is an exciting field in systems biology that provides information on metabolic outputs taking place in the system at a given moment in time. These readouts provide information relating to by-products of endogenous metabolic pathways, exogenous signals arising from diet, drugs and other lifestyle and environmental stimuli, as well as products of microbe-host co-metabolism. Thus, better understanding of the gut microbiome and host metabolic interplay can be gleaned using such analytical approaches. In this review, we describe research findings focussed on gut microbiota-host interactions, for functional insights into the impact of microbiome composition on host health. We evaluate different analytical approaches for capturing metabolic activity and discuss analytical methodological advancements that have made a contribution to the field. This information will aid in developing novel approaches to improve host health in the future, and therapeutic modulation of the microbiome may soon augment conventional clinical strategies.