Vitamin B12 Shots: Uses, Intake Levels, and Safety Do you follow a vegan diet? Did you know that vitamin b12 is mainly present in animal based products so those following a strict plant based are more likely to be deficient in vitamin Do you follow a vegan diet? Did you know that vitamin b12 is mainly present in animal based products so those following a strict plant based are more likely to be deficient in vitamin Viva! Mini factsheet: Vitamin B12