Interesting read. The thought is that the human genome is only part of the picture and to study how we metabolize or rather the chemical byproducts and relating it to various diseases. So gut bacteria no doubt is the big factor in the process in its relation to particular persons and there is some mention of IBD and probiotic effects. We'll see what becomes of this.
http://www.sciam.com/article.cfm?id=jeremy-nicholsons-gut-instincts
On a similar note, I finally read the paper on fecal flora and UC. Wow. I would like to pursue this. Only six people in the study, but all got better and years later all were in complete remission and begging the question of "is this, dare we say, a cure?" (i.e. no sign of UC, though some had scar remains, others not). There might be particular probiotics, and varieties of them that are so far only found in other "healthy" humans. Seems fairly safe if the proper precautions are taken.