One thing I notice when searching the web for "artificial sweetener danger" is that the sites promoting the dangers are often also promoting the sale of something in the "natural living" genre: books, supplements, etc. This seems to me too much like a scare tactic, directing readers to "salvation" through the products/philosophies promoted by these websites. Those that aren't seem to be merely echoing the exact same "studies" consisting primarily of anecdotal evidence.
I see a lot of "headaches" listed as symptoms ascribed to consuming artificial sweeteners, usually in the form of diet soda. I'm wondering if it isn't more the caffeine withdrawal and/or sodium causing this.
As an additional note of irony, many of these "natural living" websites speak of the dangers of artificial sweeteners, despite any scientific studies backing -- and many refuting -- their claims, then go on to list recommended supplements (which, as designated, avoid FDA testing which artificial sweeteners have overwhelmingly passed) with dubious claims based on anecdotal evidence.