hello stari and welcome to NeuroTalk.
we have a couple of forums tha ti think will really help with your questions.
here is link to our diabetic forum:
http://neurotalk.psychcentral.com/forumdisplay.php?f=53
and our vitamin and supplement forum. we have many threads started about b12.
http://neurotalk.psychcentral.com/forumdisplay.php?f=49