That's very useful, actually. I think I have a tendency to just accept the latest medical theory/practice as being the best guess that the most qualified people made with the current state of evidence. Which may be really suboptimal if they don't have a lot of evidence for it, and perhaps it should be independently examined if it concerns you personally. I am not sure what degree of belief to assign such things, though, because I have no experience with them.

Do you, or anyone, have an idea of how trustworthy such things generally are, in the modern age? Are there statistics about how often mainstream approaches are later proven to be harmful (and how often merely suboptimal)?