This issue is near and dear to my heart because it is actually what put me on the path to natural birth many years ago. I was sitting in my Microbiology class in college when the professor began talking about how breastfeeding babies have better colonies of bacteria. I was engaged at the time, so I perked up and began thinking about my own future children. She went on to say that when babies are bottle fed they will be colonized with bacteria from the water, and those are often E. coli. You may have heard of this bacteria from food contamination cases. It's a "bad" bacteria. I decided then and there to make sure I did everything I could to breastfeed my babies, which led me to natural childbirth. The important point is that once the gut is colonized it is apparently impossible to redo it. Eating healthy can improve the situation, but your initial gut bacteria are only put in there once - at birth.
Let me know what you thought of the movie!