I agree with Zapp and like his tecnique. However, my understanding is that there is so much space on the inside of the intestine, for probiotics to take hold , there must be vacancy for the healthy bacteria to latch onto. My opinion is that many things could inhibit this such as caked on fecal matter, mucoid plaque, mucus, and candida. With some of the blobs I have seen coming at of me I can see why space in my intestine was at premium. Space in my gut is like ocean front property ...scarce and very expensive. lol
It any case Zapp's theory holds water in my book.
But After having considered what I read about Andreas and his thoughts seems to me that might be true. Many of the strains we consume are not native to the human gut. Therefore they may not live in that surrounding.