I mean if the RNA is going to dissolve in the stomach acid. Then there is no way it is going to make it to the brain? And does the RNA transfer through blood on its own? That's science.
The only possible explanation is that they picked up something else along RNA that does affect memory and they are not aware of it.
I'm by no means educated about ways how RNA could get from food into your own cells, but saying "RNA is dissolved by stomach acid" is a bit too easy. HCl peaks only after a big meal with protein, and some people generally have low stomach acid. Then there's the mucosa of the mouth and esophagus, through which some food is absorbed before it even hits the digestive organs (even bypassing the liver AFAIK). It might still get dissolved as soon as it hits your bloodstream, or destroyed by antibodies, etc..
Not to the extent that you (and many others) believe. The stomach is always very acidic (pH 1–3), and this acidity is tightly regulated. Contrary to what you’ve said, the pH is raised (and hence acidity lowered) when consuming food (because HCl is used up in the digestive process). That said, much of the digestion of RNAs happens through enzymes, not acid, so the point is moot. It’s known that the human GI tract is highly efficient in digesting oligonucleotides. Very little (and of that, only small fragments) has a chance of being taken up.
A reasonable hypothesis. I like it. I'm not a scientist, so I do not know how to specifically verify or disprove it, but my understanding is that the only way to be sure is to actually perform an experiment to check; removing or controlling for all other variables.
Anyway, the tl;dr is that, at best, very short RNA fragments would survive being digested in vertebrates (but most likely not even that). This doesn’t preclude the transfer of information by RNA via food but it severely limits it.
Also, to reiterate the point I’ve made elsewhere: RNA is unstable and short-lived and therefore unsuitable as a long-term memory carrier. It can act as a short-term carrier under specific circumstances (and that’s arguably its main function in the cell anyway).
Further study is required. Facts must be established.