This study shows quite nicely that non-caloric sweeteners can alter gut microbes in mice -- a change that has negative metabolic consequences -- and provides preliminary evidence that it can happen in humans too.
Even though greater access to mass DNA sequencing technology and the emergence of bioinformatics has given us the ability to study the four pounds of microorganisms that make up the microbiome in greater detail, there's still much more that we can learn about the body's "unsung organ."
The more we've learned about the importance of our resident microbes, the more we've learned about the need and opportunity to learn more. The process may be likened to climbing a hill, and then gaining a view of the higher hills and mountains beyond. There is a lot of climbing left to do.