Vitamin B12 requirements for vegan and vegetarian diets

Vitamin B12 is a critical nutrient for blood formation, DNA synthesis, and nervous system function. Because it is found almost exclusively in animal products, the German Nutrition Society (DGE) advises that vegans and vegetarians rely on fortified foods and supplements to avoid deficiency.

While plant-based sources like algae or fermented products exist, they often provide inactive analogues that are unreliable for meeting nutritional needs. A deficiency can develop gradually, as liver stores may last months or years before symptoms appear. The DGE recommends a daily intake of 4 micrograms for adults aged 13 to 65.

Nutritional requirements vary based on life stages. The DGE recommends 4.5 micrograms daily for pregnant women and 5.5 micrograms for breastfeeding women. Other factors that may increase the body's need for Vitamin B12 include alcohol consumption and the use of oral contraceptives.