[ihnorton]

The paper contains some preliminary human data as well. From the New Scientist writeup:

But can the results in mice be extrapolated to humans? To find out, the team examined data from 381 people. They found an association between glucose intolerance and general sweetener use.

and:

To explore this, the team asked seven healthy people who don't normally consume sweeteners to eat the FDA's maximum daily allowance of saccharin. ... By day five, four of the seven people had a significant decrease in their glucose tolerance, while three saw no change. Sequencing showed that those who responded to the sweetener started out with different gut bacteria to those who didn't respond. What's more, the gut bacteria of the four responders changed significantly after consuming sweeteners, while the non-responders' barely changed.