Our bodies and our microbe communities are closely interconnected, with effects going both ways. Studies had previously shown that making changes to the microbe communities of mice could even affect the physical function and body composition of the mice.

This study aimed at addressing the same question in humans. There were certain consistent differences in microbial communities between elderly people with high ability to function physically, compared with low functioning people. These differences carried over in transplants of microbes from people to mice, and mice receiving microbes from high-functioning humans did better in tests of grip strength than mice receiving microbes from low-functioning people.

Fielding RA, Reeves AR, Jasuja R, Liu C, Barrett BB, Lustgarten MS. 2019. Muscle strength is increased in mice that are colonized with microbiota from high-functioning older adults. Exp Gerontol 127:110722.