Makes me wonder how much of the positive research on fermented foods generally has to do with liver function improvement, since the organ is crucial to the health of most of the body.
The other things seem more plausible. Purely anecdotally, my step-dad always thought he was intolerant to gluten because of his reactions to British bread, but when he spent a lot of time in France and tried bread there, he was fine.
Could be there's something about the production process of the standard British "Chorleywood loaf" that aggravates some bowels.
https://en.wikipedia.org/wiki/Chorleywood_bread_process
In general, I find it quite easy to believe that a lot of mass-produced foods contain what are essentially poisons, but I'm curious about evidential links (and I'm also aware that lots of naturally-occurring foods can be poisons if eaten too much, but that's a different question)
"I travelled somewhere and things improved" has the serious complication that you changed almost everything at once and possibly removed major stress sources. You were even outside of your own home - and buildings have ecosystems themselves anyway as well as just systemic faults.
I would just add that when he got back to Britain and tried baguette style bread there he found that he could tolerate it in Britain too.
Again, I'm just reporting a story as it was told to me because I was reminded of it in response to the previous comment.
The obesity epidemic started rapidly around 1980, but it's unlikely diet changed for the worse since then.
Also, it happened to lab animals and pets as well.
https://royalsocietypublishing.org/doi/abs/10.1098/rspb.2010...
Also, it appears to be correlated with low altitudes and interventions that cause you to move to higher altitudes cause weight loss.
https://journals.plos.org/plosone/article?id=10.1371/journal...
> Purely anecdotally, my step-dad always thought he was intolerant to gluten because of his reactions to British bread, but when he spent a lot of time in France and tried bread there, he was fine.
The American equivalent of this (people who go to Europe and think the bread is healthier because it's easy to digest) is because we fortify wheat and the extra nutrients esp. iron cause stomach discomfort.
In contrast, antibiotics often kill a strain of a few off completely, while suppressing everything else except for a few strains that resist the antibiotic, which also creates a massive opportunity for new bacteria to colonize. And these deficits are partially heritable.
Far less common now as dishwashers became cheaper and more ubiquitous.
Sixty plus years here and four generations of our family and most people we know rinse off plates and glasses and vigorously dry with a fresh towel.