That is not fully true. I have a friend who suffered from candida back then, and her douching was medicinal. I think that sequence affected her whole life.
(Using her bathroom as a guest was a learning experience.)
Around the same time, via a boss who was a specialist in various immune disorders, I became aware of a patient with (I forget the term, but it meant rampant) candidiasis. The good bit is that that old friend is still ok.