The diversity of the gut microbiomes of elderly people is linked to their health, reports NPR. A recent study published in Nature by University College Cork's Paul O'Toole and his colleagues compared the fecal microbiota of 178 people between the ages of 64 and 102, who lived independently or in out-patient day hospitals, rehabilitation hospitals, or long-term care facilities. The researchers found that participants who lived independently had a more diverse diet than those who lived in care facilities, and that people in long-term care had less diverse microbiota than people who lived independently. In addition, the researchers found an association between a decrease in microbe diversity and frailty, reduced muscle mass, and worsening mental state. NPR notes that many factors could be in play, though O'Toole says that diet is an important aspect. "We were surprised that the correlations between microbiota and health came out so strongly," he tells NPR.
In an editorial, The Guardian adds that "since this diversity also correlated with diet, the lesson is clear: variety is not just the spice of life, but its staple. We are what we eat, and so are our inner friends."