Impact of real-world diet variations on the gut microbiota in humans and humanized mice
The study aimed  to  clarify  the  impact  of  'real-world' dietary variations on  gut  microbiota  composition by  asking  healthy human volunteers to eat exclusively a vegetarian ready-made meal ('healthy') for three days followed by a meat-based ready-made meal and high-sugar drink ('unhealthy') for two days. We showed that the  microbiota  varied  between  individuals  and  within  individuals  regardless  of  diet. However, when  we  transferred  microbiota  from  individuals on  the  healthy  diet  to  germ-free mice fed  the healthy human diet  then  swapped  to  the  unhealthy  human diet,  we  observed  significant, often donor-specific, changes in the mouse microbiota following the mild dietary intervention. These  results  suggest  that  feeding  humanized  mice  human  diets  may  facilitate  understanding of human microbiota responses to mild dietary changes.