"Researchers from University College Cork in Ireland have recently analyzed the bacteria living in the intestines of more than 170 people over 78 years of age. They found that the gut microbiota varied according to the environment where they were living (at day care, in hospital, at home) and also according to what they ate. In general, people living in community were healthier and had a more diverse gut microbiota than people living in long-term care, who were also weaker. Authors of the study, recently published in Nature Magazine, believe that these changes in gut microbiota composition and the related loss of health status are driven by diet."
How diet impacts gut microbiota and health in the elders | Gut Microbiota Worldwatch