I have been reading around on problems that have been mentioned on this forum, and I recently came across a article about weak pelvic floor and sphincter muscles in the bowel.
The sphincter muscles I believe are the muscles which hold the gases and feces until you need to defecate. So in theory, if odors are coming out quite frequently, it might mean that the muscles have become weaker and are not responding in the way they should and therefor not holding the gases etc. in. In some cases the body loses the sense of when to go defecate and the body just stores the feces in the bowels, maybe its this loss of sense, and the build up of feces in the bowels that is causing the smell.
Maybe the solution is to strenghten and train the pelvic floor and sphincter muscles.
Its just one of many theories, I would be really intersted if any one has an opinion on this, or further information please reply!!!