Quick answerVitamin B12 is not reliably found in unfortified plant foods, so vegans need fortified foods or a supplement. The Vegan Society recommends either eating fortified foods two or three times a day (at least 3 micrograms daily), taking a daily supplement of at least 10 micrograms, or taking a weekly supplement of 2,000 micrograms.

Vitamin B12 is the one nutrient that every vegan and most vegetarians need to plan for. It is made by bacteria, not by plants or animals, and in modern food systems it reaches people mainly through animal products. The good news is that fortified foods and supplements make it straightforward to get enough. This guide explains how.

Key takeaways

• Unfortified plant foods are not reliable B12 sources.
• Use fortified foods two or three times a day, or a supplement.
• Organic plant drinks are usually not fortified.
• See your GP if you notice symptoms of deficiency.

Why is vitamin B12 important?

Vitamin B12 contributes to normal red blood cell formation, the normal function of the immune system, normal functioning of the nervous system, normal psychological function and the reduction of tiredness and fatigue.

According to the NHS, adults aged 19 to 64 need about 1.5 micrograms of vitamin B12 a day. The nutrient reference value (NRV) shown on UK food labels is slightly higher, at 2.5 micrograms. Because the body stores B12 in the liver, deficiency can take years to develop, which is why a low intake can go unnoticed for a long time.

Which vegan foods contain vitamin B12?

Reliable vegan sources are almost all fortified, meaning B12 has been added during manufacture. Common options in UK shops include:

Fortified food	How to use it	What to check
Plant-based drinks (soya, oat, almond)	Cereal, tea, coffee, smoothies	Look for B12 on the ingredients list; organic versions are usually not fortified
Breakfast cereals	Daily breakfast	Many are fortified; check the nutrition panel
Yeast extract spreads	Toast, gravies, stews	Some brands are fortified; salty, so use thinly
Nutritional yeast flakes	Sauces, popcorn, pasta	Only fortified versions contain meaningful B12
Plant-based yoghurts and spreads	Snacks and cooking	Fortification varies by brand
Meat alternatives	Main meals	Some are fortified; check labels

An important tip: under UK and EU organic rules, organic plant drinks generally cannot be fortified. If you choose organic for other reasons, make sure B12 is coming from elsewhere in your diet.

Why fortified foods should be spread through the day

The body can only absorb a small amount of B12 at once through its main absorption pathway. That is why the Vegan Society suggests eating fortified foods at least two or three times a day, rather than relying on one portion.

A sample day using fortified foods

Here is how a vegan could spread fortified foods across a typical day:

• Breakfast: a fortified breakfast cereal with a fortified soya or oat drink.
• Lunch: a wholemeal sandwich with a thin layer of fortified yeast extract, or a soup sprinkled with fortified nutritional yeast.
• Dinner: a pasta sauce or curry finished with fortified nutritional yeast, or a fortified meat alternative.
• Drinks: tea or coffee with a fortified plant drink.

Amounts differ between brands, so read the nutrition panels and add them up roughly. If you regularly miss one of these occasions, a supplement offers a useful safety net.

Which “natural” B12 sources are unreliable?

Some foods are often described as vegan B12 sources, but they are not dependable:

• Spirulina and chlorella: may contain B12-like compounds (analogues) that the body cannot use.
• Seaweeds such as nori: contain variable amounts, and some of it may be inactive.
• Fermented foods such as tempeh and miso: amounts are inconsistent and usually very small.
• Mushrooms and unwashed vegetables: contain traces at best.

These foods can be part of a healthy diet, but they should not be relied on for vitamin B12.

Should vegans take a B12 supplement?

For many vegans, a supplement is the simplest and most reliable option, especially if fortified foods are not eaten several times a day. The Vegan Society’s guidance offers two supplement routes:

• Daily: a supplement providing at least 10 micrograms.
• Weekly: a supplement providing 2,000 micrograms.

These amounts look high compared with the daily requirement, but that is because absorption from a single large dose is much less efficient. The NHS says that taking 2 milligrams (2,000 micrograms) or less a day of vitamin B12 from supplements is unlikely to cause harm.

Cyanocobalamin vs methylcobalamin: which form?

You will see different forms of B12 on supplement labels:

• Cyanocobalamin: the most widely studied and stable form, commonly used in fortified foods and supplements.
• Methylcobalamin: an active form popular in “natural” supplements. It is a valid choice, though it is less stable.
• Adenosylcobalamin: another active form, sometimes combined with methylcobalamin.
• Hydroxocobalamin: mainly used in prescribed injections.

For healthy adults, any of these can work. The most important thing is choosing a product you will take consistently. Some supplements combine B12 with folate or other B vitamins; these can be useful, but check that the B12 amount alone meets the guidance above and that you are not doubling up with a multivitamin.

Tablets, chewables, sprays or drops?

B12 is available in many formats. Chewable tablets, sublingual lozenges, oral sprays and liquid drops can all suit people who dislike swallowing tablets. Check that the product is labelled vegan, as some capsules use gelatine.

Who needs to take extra care with B12?

Some people are at higher risk of low B12, whatever their diet:

• Pregnant and breastfeeding vegans, as B12 is essential for the baby’s development.
• Older adults, who may produce less stomach acid and absorb B12 from food less well.
• People taking metformin or long-term proton pump inhibitors such as omeprazole.
• People with pernicious anaemia or digestive conditions affecting the stomach or small intestine. These conditions often need B12 injections prescribed by a GP, and supplements are not a substitute.

Children on vegan diets also need a reliable B12 source. Speak to your GP, health visitor or a registered dietitian before giving supplements to children.

What are the signs of low vitamin B12?

According to the NHS, symptoms can include extreme tiredness, lack of energy, pins and needles, a sore red tongue, mouth ulcers, muscle weakness, problems with vision, and changes in memory or mood. Some nerve-related effects can become permanent if not treated, so do not wait if you notice these symptoms. A simple blood test from your GP can check your levels.

Building a complete vegan nutrition plan

Vitamin B12 is one piece of the puzzle. Vegans also need to think about vitamin D in autumn and winter (see our UK vitamin D winter guide), iodine, and omega-3 fats, where algae oil is a plant-based option covered in our fish oil vs algae oil comparison. Magnesium is usually easier, as our magnesium-rich foods shopping list shows.

You can find vegan B12 supplements and fortified wholefoods at the BeWell health food shop in Chelmsford, where our team can help you compare forms and strengths.

Frequently asked questions

What vegan food is highest in vitamin B12?

Fortified foods such as fortified nutritional yeast, breakfast cereals and plant drinks are the most reliable vegan food sources. Amounts vary, so check labels.

Do vegans need to take B12?

Vegans need a reliable B12 source. That can be fortified foods eaten several times a day or a supplement. Many vegans find a supplement simpler.

Is spirulina a good source of B12 for vegans?

No. Spirulina mostly contains inactive B12 analogues and should not be relied on.

How much B12 should a vegan take daily?

The Vegan Society recommends at least 10 micrograms a day from a daily supplement, or 2,000 micrograms once a week.

Can you take too much vitamin B12?

B12 has low toxicity, and excess is usually passed out in urine. The NHS says 2,000 micrograms or less a day from supplements is unlikely to cause harm. Unusually high blood levels without supplementation should always be discussed with a doctor.

Medical DisclaimerThis content is for general information only and is not a substitute for professional medical advice. Please consult your GP, pharmacist, or qualified healthcare professional before starting any new supplement, especially if you are pregnant, planning a pregnancy, breastfeeding, taking medication, managing a health condition, or considering supplements for children.