Well, since it is known that about 98% of digestion occurs in the stomach and small intestine, I doubt that whatever reaction that occurs in the colon is antything more than negligible. Pollen is something I try to stay away from, since I now have seasonal allergies. Eating it is the last thing I'd want to do. As far as I can tell, there is no evidence that bee pollen has any proven health benefits, and any claims that are made are by those selling it. There is no real research on the product. Plus, as an unregulated product, you don't even know if what you are buying is just bee pollen.
http://en.m.wikipedia.org/wiki/Bee_pollen
That said, I'd be interested in hearing what it does for you or others.
Jan