NutritionFacts.org is sponsored by the Jesse & Julie Rasch Foundation in partnership with Michael Greger, M.D. Dr. Greger shares nutrition-related research, as published in scientific journals and has put together a nice article regarding the importance of B12 in vegetarian and vegan diets.
Dr. Greger is stating that since the CNN airing of The Last Heart Attack featuring Bill Clinton, pundits are saying one shouldn't go the veggie route because of a B12 deficiency.
Supplementation is KEY, and see Dr. Greger's article here for more details. B12 Supplementation is easy - dealing with the aftermath of a Heart Attack is not.