I have read that vegan people in India don't suffer as many B12
deficiencies as vegans in developed countries do because of a lack of
insecticides for use on their produce.  B12 is only available from animal
sources and insects and worms will provide enough if your fruits and
vegetables are organic and stored where insects can lay their eggs to
hatch larve.

Ray Audette
Author "NeanderThin:A Caveman's Guide to Nutrition"
http://www.sofdesign.com/neander