Vegan Vitamin B12 – Very low B12 intakes can cause anemia and nervous system damage. The only reliable vegan sources of B12 are foods fortified with B12 (including some plant milks, some soy products and some breakfast cereals) and B12 supplements. Vitamin B12, whether in supplements, fortified foods, or animal products, comes from micro-organisms. Most vegans consume enough B12 to avoid anemia and nervous system damage, but many do not get enough to minimize the potential risk of heart disease or pregnancy complications.