The challenge I think modern medicine has is that in order to prescribe a solution it does need to understand the problem and how your gut might be responsible for it. As we know the medical world takes time to adapt and so it takes more than just a few studies to require doctors and GP's to understand it, better yet be equipped to prescribe a solution.

For many of these gut health related issues, I think most people would be better off seeing a dietitian or even as you say functional medicine doctors. As Tim Spector has been saying, so many ailments resulting from the gut can be fixed through eating a more organic/wholefoods diet. This takes time and isn't easy to do.