To treat vitamin B12 deficiency, intramuscular injections, oral pills, or sublingual lozenges

can similarly effectively increase the level of vitamin B12 at sufficient doses.

But this is based on blood-level targets rather than assessing clinical outcomes in terms

of symptom improvement.

So some believe that at least initially injected B-12 should be the first-choice treatment

for patients with severe B-12 deficiency, though even with the best treatment,

neurological symptoms may take several months or even years to resolve and may never

get better, so it's better to prevent deficiency in the first place.

B-12 is made by plants or animals, but rather by bacteria.

So feces are a good source of vitamin B-12.

That's one of the ways our fellow great apes like gorillas get B-12. Evidently dining on dung was seen to be more common after wet weather, though,

leading to the suggestion that, besides its nutritional importance,

it may be just that they want something warm to nibble on at the end of a long, cold rain.

Thankfully, since the advent of modern sanitation

bacteria and feces are happily no longer reliable sources of vitamin B-12 for humans. A large

proportion of the bacteria in our gut do make B-12, though, but it's always been thought to be produced

too far down to be absorbed. How do we know? Because if you squirt radioactively labeled B-12 into people's rectums, they don't really seem

to absorb it. But the human colon is about five feet long, and it was just squirted in about

a foot. What about higher up? No B-12 update from the human colon had ever previously been

described or considered

until now.

B-12 was squirted via colonoscopy all the way up at the beginning of the colon, and B-12 is

...