Nutrition
Do vegans need vitamin B12?
Short answer
Yes. B12 is not reliably present in unfortified plant foods. Reliable sources are a supplement and fortified foods (some plant drinks, cereals, fortified nutritional yeast).
This is not a matter of opinion – B12 from supplements or fortified foods is recommended by the NHS, The Vegan Society and Poland’s National Centre for Nutrition Education, among others. Deficiency can lead to anaemia and nerve damage. In adults, symptoms usually take years to appear because the body has stores.
It matters most in pregnancy and breastfeeding: babies of B12-deficient mothers develop symptoms quickly, and the damage to the nervous system can be permanent.
Do not rely on fermented foods, spirulina or seaweed – they contain mostly inactive B12 analogues. The simplest option is a cyanocobalamin tablet or regular fortified foods (doses are in “How much B12 should vegans take?”). This is not a weakness of the diet, just part of the plan.
Sources
- Vitamin B12 — Fact Sheet for Health Professionals
- Vegetarian Dietary Patterns for Adults: Position Paper of the Academy of Nutrition and Dietetics (2025)
- Vegetarian, vegan and plant-based diet — British Dietetic Association
- The vegan diet — NHS
- What every vegan should know about vitamin B12 — The Vegan Society
- Praktyczny przewodnik po diecie roślinnej — NCEŻ PZH (2025)