Prior Dietary Practices and Connections to a Human Gut Microbial Metacommunity Alter Responses to Diet Interventions

Ensuring that gut microbiota respond consistently to prescribed dietary interventions, irrespective of prior dietary practices (DPs), is critical for effective nutritional therapy. To address this, we identified DP-associated gut bacterial taxa in individuals either practicing chronic calorie restriction with adequate nutrition (CRON) or without dietary restrictions (AMER). When transplanted into gnotobiotic mice, AMER and CRON microbiota responded predictably to CRON and AMER diets but with variable response strengths. An individual’s microbiota is connected to other individuals’ communities (“metacommunity”) by microbial exchange. Sequentially cohousing AMER-colonized mice with two different groups of CRON-colonized mice simulated metacommunity effects, resulting in enhanced responses to a CRON diet intervention and changes in several metabolic features in AMER animals. This response was driven by an influx of CRON DP-associated taxa. Certain DPs may impair responses to dietary interventions, necessitating the introduction of diet-responsive bacterial lineages present in other individuals and identified using the strategies described. [Display omitted] •Dietary practices can alter bacterial diversity in the human gut microbiota•Microbiota responses to diets vary in strength across individuals•Promoting bacterial dispersal between host microbiota enhances responses to diets•Metacommunity dynamics have implications for effective nutritional interventions Ensuring that gut microbiota respond consistently to dietary interventions is critical for nutritional therapy. Griffin et al. find that dietary practices alter the human gut microbiota. The magnitude of microbiota responses to diet interventions varies among individuals. Dispersal of diet-responsive bacterial taxa between hosts enhances subsequent responses to diet interventions.