This is an excellent 8 minute presentation on whole food, vegan sources of some macro and micro nutrients, also which nutrients need to be supplemented. It just posted today here... I don't know if it's a complete discussion on the topic, but I think it's a good start. Brenda Davis is a highly respected vegan nutritionist, author, and advocate in Canada. For those who eat more of a paleo style diet, like me, I found her statement that 10% to 30% of adults over age 50 do not have adequate stomach acid and enzymes to cleave B-12 from animal protein.