Unlike most other vitamins, vitamin B12 is not made by plants or animals. Rather, it is made from bacteria. Thus, the argument that vegans can make their own B12 from intestinal bacteria seemingly makes sense. Some nutritionists like Dr. Charles Partito make compelling arguments about the existence of B12 in plants. Of course, the guy is trying to sell you his cleansing products though. The same goes for Dr. Vivian Vetrano who says that B12 coenzymes are readily found in raw plants. She’d like you to join her retreat.