Is Vitamin B12 an uninformed vegetarian at risk for deficiency?

Meat eaters converted to vegetarians store up to about 5 years worth of B12 before the supply is depleted. Most multi-vitamins contain B12, so if you take a vitamin supplement, you will probably be fine. Anyone new to vegetarianism should do a little research on nutritional requirements. It is well documented on the internet that B12 is a necessity and it is not present in vegetables. There are vegetarian sources, mostly notably in nutritional yeast (however, not all nutritional yeast has been fortified with B12, so check the label). Also to note that energy drinks often supply large quantities of B12. Monster, Red Bull and Rock Star are known to be vegan friendly and contain B12.