I can't find the original article unfortunately, but I can provide a bunch of information that supports that claim:
* Well, meat is no a large (or any) part of the diet of people in many of the poorer parts of the world.
* Animal sources, are the only real sources of vitamin B12 (though yeast is an animal source, so this doesn't necessarily mean 'mammals' or 'fish').
* Feces contains B12[1][2]
* B12 is water soluble.
* In parts of the world where the water is 'untreated,' it is contaminated with feces to some amount. Obviously, the more people and animals that use the water source, the more this is true.
Vitamin B12 is not found in vegetables: it is available,
however, from faecally contaminated water, and this source
is important in the poorest vegetarian societies.
So if you went to such a society and decontaminated their water supply, you would end up with a population suffering from B12 deficiency.
* Well, meat is no a large (or any) part of the diet of people in many of the poorer parts of the world.
* Animal sources, are the only real sources of vitamin B12 (though yeast is an animal source, so this doesn't necessarily mean 'mammals' or 'fish').
* Feces contains B12[1][2]
* B12 is water soluble.
* In parts of the world where the water is 'untreated,' it is contaminated with feces to some amount. Obviously, the more people and animals that use the water source, the more this is true.
[1] http://www.beyondveg.com/billings-t/comp-anat/comp-anat-7c.s...
[2] http://www.sfgate.com/cgi-bin/blogs/parenting/detail?entry_i...
There was a single article that made that claim, but I can't find it right now. All I can provide...
-- later --
I found this: http://books.google.com/books?id=CF2INI0O6l0C&pg=PA209&#...
Not the original source that I read, but states:
So if you went to such a society and decontaminated their water supply, you would end up with a population suffering from B12 deficiency.