I don't know what it does with 3-lac, but according to David Websters book, Bentonite makes the Colon alkaline which is the opposite of what good bacteria need to grow.
I know a lot of people like P&B shakes, but all it did for me was stop me up. I might as well have ate concrete. I have been doing colonics and it took 2 or 3 sessions before it broke loose. I will never take it again.