I don't know much about this except it has to do with good bacteria/flora that inhabit the upper intestine and are helpful to have. I know with constant diaheria that comes from having CD and eating gluten these are stripped from the intestines. I was talking to some friends about it and they suggested using probiotics. I know that they are quite expensive and I am already at budget crunch with buying all these gluten free foods, and flours, etc. So I decided to try so Kefir.
I am currently trying this one, it is lowfat, kosher, and organic
Lifeway Peach Kefir
So if anyone has any helpful first hand info on this I'd appreciate hearing about it. I read somewhere that it can help you loose weight too.