While it is possible to have a nearly complete diet eating vegan, Vitamin B12 is not present in any plant-based foods. Many cereals, plant-based milks, and nutritional yeast are fortified with B12, or you can take it daily or weekly as an oral supplement. Vegan B12 supplements are derived from bacterial cultures, not animals–just make sure they're not packed in gelatin capsules. A B12 deficiency can have enormous impact on well-being. Many dietitians recommend that levels be monitored regularly by a medical professional.
Additionally, there are a few vitamins and minerals that vegans may have depleted supplies of. Vitamin D has been highlighted for its role in health protection, with notable functions in bone health, immune health, nervous system, and muscle function. Studies have found vegans to have lower levels of vitamin D compared to carnivores. To obtain adequate vitamin D, vegans must rely on mushrooms exposed to light, fortified food products, sunlight exposure, and supplements. Important for bone health and muscle and nerve function, vegans often consume lower levels of calcium. Of particular concern is risk for osteoporosis; some studies have shown lower bone mineral density among vegans. Vegan calcium food sources include calcium-fortified plant-based milks and orange juice, tofu made with calcium sulfate, leafy greens, broccoli, butternut squash, beans and almonds, Supplements may be considered to help meet needs. Found in the hemoglobin of red blood cells, iron is necessary for oxygen transport through out the body. It also plays a key role immunity and DNA synthesis. Heme iron (from animal sources) is absorbed better than non-heme iron (from plant sources). Vegans can be at risk for iron deficiency. Sources of iron for vegans include legumes, leafy greens, grains, tofu and enriched cereals. The absorption of iron can be enhanced by soaking, sprouting, fermenting and cooking beans, grains and seeds. In addition, the presence of vitamin C with iron sources can also increase its absorption, as well as cooking foods in an iron skillet. Zinc impacts the immune system and structure of DNA. Studies show that some vegans have slightly lower zinc levels, though more research is needed. Zinc may be found in nuts, whole grains, soy, and beans. However, bioavailability of zinc may be decreased due to the presence of inhibitors in plant sources. It is recommended that vegans consume 50% more than the current DRI recommendations for zinc.