It only took 20 years to work its way into the public/popular media. (In the meantime, a lot of margarine was sold -- and a lot of angioplasties and bypasses.)
Running was supposed to destroy one's joints. Now, we learn that when it is not overdone (too much in too short a period of time or with too little prior conditioning), it actually strengthens joints.
I've become increasingly skeptical of new health effect claims, particularly when they aren't backed up by detailed, specific (to the aspect of health under consideration), and longitudinally significant evidence.
(Oh, and remember when vitamin D was considered one of the less significant vitamins (once you had enough in your diet to prevent rickets)?)
[Meta: Sigh, I have indeed become that "grumpy old man".]
I don't know. Assuming you went through the normal college course straight out of high school I'm ~12 years younger than you but I've been coming around to the same conclusions. Personally I think between the internet and some other things it's just that we're getting the data now that says that we need to tune our trust of science down a bit. I still think it's the best way of learning there is, it just isn't as powerful in practice as we'd like.
I remember thinking in the 1990s that as I read about the history of various sciences, the only fields where the dominant consensus didn't spend long periods of time being dead wrong were fields too young to have a dominant consensus. (Perhaps not in those words at the time, but along those lines.) I recall seeing the casual assumption that all that stuff was in the past, and wondered what major sciences were actively wrong. It turns out that in fact they weren't all exactly right and indeed I think that some entire major fields were wrong at the time.
(Bringing up the interesting question of who is wrong today? Back then I could mouth the words but hadn't really internalized the idea, but now I seriously wonder, who is wrong today in a way that I don't even suspect? The odds of it being "nobody" are basically zero.)
Science != popular reporting/understanding of science.
But the point about some of our understanding being wrong is right on the money.
Recently a paper went by on how something like 90% of medical studies are not able to be replicated in follow-up studies. If you really understand science qua science (as opposed to science-as-religion-substitute), you should understand this isn't a minor interesting tidbit to be discarded, this is a dagger to the heart of the field. Other fields seem to be having similar problems.
I reiterate, science is still the best we've got and I don't anticipate a replacement. But the evidence strongly suggests that the quality of the real science being done is a lot lower than it may appear at first glance, or what some people would have you believe.
Actually, it's really amazing how many dangerously wrong ideas medicine has come up with over the years.