Vitamin B12 for Vegetarians and Vegans: Fortified Foods, Supplements and Testing

What the sources say

• NHS (UK): B12 is not found naturally in fruit, vegetables and grains, so vegans may not get enough of it. [3] The NHS advises vegans to have fortified foods or consider supplements for nutrients that are harder to get on a vegan diet. [4]
• Academy of Nutrition and Dietetics (US, 2016 position paper): vegans need reliable sources of vitamin B-12, such as fortified foods or supplements. [2] The same statement says appropriately planned vegetarian and vegan diets are appropriate for all life stages, including pregnancy, lactation, infancy, childhood, adolescence and older adulthood. [2]
• MedlinePlus (US, 2025): some nutritional yeast products also contain B12, [1] and the B12 used to fortify foods is very easy to absorb. [1]
• NHS treatment page: people who find it difficult to get enough B12 in their diets, such as those following a vegan diet, may need B12 tablets for life. [5] Fortified breakfast cereals can be a good source for vegetarians, says MedlinePlus. [1]

How strong is the evidence?

Evidence label: established nutritional role for the need for a reliable source; the studies below measure intake or blood markers, so see the strength column.

Blood markers are not the same as health outcomes. These studies measure status, not whether anyone developed anaemia or nerve problems.

Official intake figures

These are population reference values, not personal instructions, and each body sets its own. The B12 form is not specified by these sources.

The figures differ because bodies use different methods. See RDA, AI, DV and UL. For an upper amount, the NHS says there is not enough evidence on the effects of high-dose B12 supplements but that 2 mg or less a day is unlikely to cause harm. [3] We did not find a US upper limit on a source we could read.

Food sources and plant claims

The NHS lists fortified foods such as some yeast extracts, breakfast cereals and soy products. [5] Fortification varies by product and country, so check the nutrition label. See foods high in vitamin B12 for the full food list.

Claim check, "natural" plant B12 (seaweed, algae, fermented foods, unwashed produce): Proper evidence not found that these are reliable sources. We searched PubMed on 2026-10-23 for studies of B12 in algae and fermented plant foods in vegans and found none we could read. MedlinePlus says B12 is not present in plant foods unless fortified. [1]

Testing and when to ask a clinician

Do not diagnose B12 deficiency from symptoms. The NHS says deficiency is often diagnosed from symptoms and a blood test, and that some problems can be irreversible if treatment is delayed. [9] The body stores B12 in the liver, which MedlinePlus says can last a few years, so problems can develop slowly. [1] See B12 tests and vitamin B12 deficiency.

Ask a clinician or pharmacist before choosing supplements if you are pregnant, breastfeeding, giving a child a vegan diet, have kidney or liver disease, will have surgery, or take medicines. See medication interactions, prenatal vitamins and vitamins for children and teens. Supplement quality varies. See quality testing and certifications. For the wider diet, see supplements in vegetarian and vegan diets.