> And that many common chronic disorders/illnesses (including ADHD, Autism, weight gain, etc) in our generation are actually attributable to a disfunctioning microbiome
That's absolutely not true. Diabetes for instance used to be extremely rare and limited to the elites.
And, for instance, ADHD probably isn't a disorder if you live a very simple life and do manual labor all day. No hyperactivity, no DMV appointments, and your life is decided for you. Remember, all the lines are drawn arbitrarily and something is labeled a disorder when it doesn't work with our (very strange) modern world.
Can't comment on autism though, and this is not directly about micro biome obviously.
A lot of exercise increases focus and reduces fidgetiness. Also, if there's fewer things to keep track of and less everyday choices to make, it's easier.
I have ADHD bad but it virtually goes away while backpacking for reasons I described.
In the 1960s you had to learn to mask your differences or you would suffer violence directed at you. We used to beat kids for not behaving in the ways we expect.
Get enough beatings, you learn to hide the thing that gets you beat.
I'm not at all convinced it was less common back then, just more hidden.
Another confounding variable is that we got so much better at testing many things that we have people living long enough to clearly manifest problems that may not have decades or centuries ago.
Sort of like how a big part of the increase in cancer deaths are people living long enough to die of cancer.
All of those things have existed for ... ever