The cobalamins are made only by microorganisms, not by plants or animals. This means that animals must obtain them either from their diet or from microorganisms living in their bodies. For example, cows get their vitamin B12 from gut-dwelling bacteria. Since the cobalamins are stored in animal cells, carnivores can get their vitamin B12 by eating meat, even though they don’t themselves have B12-producing gut-dwelling bacteria. Herbivores that lack B12-producing bacteria (such as human vegetarians or pet animals) will develop B12 deficiencies unless they use some kind of B12 supplement. In fact, it has been found that around 60-70% of vegetarians have vitamin B12 deficiencies! Left untreated, such deficiencies will eventually do permanent damage to the body.
Synonyms: methylcobalamin, mecobalamin, methyl-B12, methyl vitamin B12, Vancomin