My apologies.
I had vaguely remembered a research paper on this and ended up on the 2017 Springer document so my knowledge is limited to that specifically.
While it is a complicated subject I'll try to adjust the note to refer to this comment.
thanks!
gut bacteria composition is so complicated and still so under-researched…
I think the main thing two things I would emphasize are
1. that it’s received through your environment, not your genes. it seems to be mostly in Japanese populations, but theoretically you could “give” someone the bacteria and it would live in their gut just fine.
2. that while the porphyra polysaccharide is a significant part of “nori”, nori is made up of a lot of things, and the ability to digest that is present in other populations. (
one paper even mentions that specific bacteria for digesting agar are present in both Japanese and North American populations.) so it’s not like it’s “indigestible” to non-Japanese people, and it’s not like Japanese people are the only ones with special bacteria (but ones for porphyran seem to be a bit more unique).
(I read a bit more of some articles, so I wanted to comment with more info, such as about the agar digestion. it’s a very interesting subject.)
(also, other populations around the world have been eating seaweed since ancient times, but for various reasons (capacity of the seaweed to be farmed at an industrial scale, negative associations with poverty food, etc) they aren’t necessarily common or well-known. laverbread, for example, is made with another edible seaweed.)