Remember, beer itself is somewhat acid, and the article seems to be referring to the small intestine, where the stomach acid has been somewhat neutralized, when it talks about "the gut." The temperature is right, and saliva and stomach acid will go a long way towards breaking starches down into simple sugars, so, heck, especially after a run of antibiotics wiping out the usual gut flora, why not?
Dude should just be glad he doesn't mess around with farmhouse ales or sours -- I wouldn't put it past brett to start working on your intestinal lining after it finished up with the bagel.