Have you noticed how the media is always telling us a different health 'tip'? Of course they typically go along with the latest hot diet, right? I suppose they're all probably good for you in some way, but not everyone has the same issues, so the same tricks aren't going to help us all.
I'm sure it can also be attributed to all of the advances in medicine. They can test for so much more than they used to! But then in the same breath I find myself wondering if that makes things better or worse. Lately I've heard of a few people with vitamin D deficiencies. I'm not doubting the validity of the problems this can cause, but I don't think the deficiencies are new, I just think they're one of the new hot buttons doctors are checking for.
Remember when everyone was in search of cholesterol treatments? I don't hear as much about it anymore. Is everyone cured, or has the moment passed for that to be the popular health struggle?
Weren't the original personality types based on body fluids? I'm just spouting a bit here (get it? that was a pun!) - but I remember theories well before my time saying the reason you acted the way you did was because you had too much blood, or phlegm or whatever. Things keep evolving, but no one has the perfect chemical makeup, eh?