Dietary influences on the microbiota and microbial metacommunity

▸ Griffin NW, Ahern PP, Cheng J, et al. Prior Dietary practices and connections to a human gut microbial metacommunity alter responses to diet interventions. Cell Host Microbe 2017;21:84–96.

Westernisation is associated with a lower taxonomic and functional diversity, which can be partially restored by dietary interventions. Microbial communities of cohabitating individuals develop similarity, indicating that transfer of gut taxa occurs between people with close proximity. The relative strengths of selection and dispersal in influencing community structure and diversity can vary across different metacommunities. Currently little is known about how diet impacts selection and dispersal impacts responses. This could identify microbial impact of different dietary patterns, predict individual responses to diets and determine therapeutic dietary interventions. A key question is whether individuals have the capacity to respond to a given dietary intervention in a similar manner or whether variation in their community structures leads to marked interpersonal differences. This paper examined gut microbial community structure in two groups of people living in the USA who exemplify distinct dietary patterns: those who practice chronic calorie restriction with optimised intake of nutrients (CRON) and those without prescribed or self-imposed dietary restrictions (AMER). Dietary practices altered the human gut microbiota but the magnitude of microbial response varied among individuals. Transplantation of AMER or CRON faecal microbiota into gnotobiotic mice responded predictably to CRON and AMER diets with variable strength. Sequential cohousing AMER-colonised mice with CRON-colonised animals resulted in enhanced response to CRON dietary intervention, and changes in metabolic features in AMER mice driven by a shift towards a CRON-associated microbiota. This highlights the preprogrammed nature of the gut microbiota that is strongly resistant to change. Ensuring that gut microbiota respond consistently to prescribed dietary interventions, irrespective of prior dietary practices, is critical for effective nutritional therapy.

Predisposition to GI tumour development

▸ Hua G, Wang C, Pan Y, et …