I know it contains phytic acid and such, but have you tried psyllium husks? I use that every other day for regularity and it works wonders. There's also the psyllium and Bentonite shakes that everyone talks about on curezone--I haven't tried them, but apparently it can help absorb toxic material. Other good sources of fiber include oat bran and flax seeds, but I've had better luck with psyllium personally.