Vitamin B12 deserves attention whatever you eat. Your body needs it to make healthy red blood cells and DNA, and to keep your nervous system working properly. Getting enough matters whether your meals are fully plant-based, vegetarian or include meat and dairy. [2]
Vitamin B12
Supports blood cells and healthy nerves
Reliable sources
- Reliable supplement
- B12-fortified foods
- Fortified nutritional yeast
Unfortified plant foods are not a reliable B12 source. Check labels and your supplement schedule.
Sources [2] [15]There are two things to think about: where your B12 comes from, and whether your body can absorb it. Animal foods can provide B12, but eating them does not rule out deficiency. Some health conditions, stomach or bowel operations, and medicines can affect absorption. [3] [9]
If you eat a vegan diet, reliable sources are fortified foods or a suitable supplement. Vegetables, beans and wholegrains have plenty to offer, but they cannot be relied on for B12. [1] I want to help you understand what to check, how to plan a dependable source and when it is worth asking for support.
Where does vitamin B12 come from?
Vitamin B12 is also called cobalamin. It is made by microorganisms, rather than being a bacterium itself. Animal foods can contain it, while the reliable plant-based options have B12 added to them, as fortified foods or supplements. [1] [3]
Dr Michael Greger puts the practical message clearly on NutritionFacts.org:
“A regular, reliable source of vitamin B12 is critical for anyone eating a plant-based diet.”
Dr Michael Greger, NutritionFacts.org [4]
I like having something concrete to check. With B12, that means being able to point to the food label or supplement that provides it, rather than assuming a varied diet will take care of everything.
Where can I get B12 without animal foods?
Look for foods labelled as fortified with vitamin B12. Options include some plant drinks, breakfast cereals, nutritional yeast and yeast extracts. The amount varies between products, so check the actual pack. Nutritional yeast without added B12 does not become a reliable source simply because it looks like a fortified brand. [1] [5]
For example, you could use a fortified drink in porridge or add fortified nutritional yeast to a sauce. Choose foods you enjoy, then check how much B12 your usual serving provides. A spoonful or splash may be much smaller than the serving used on the label.
Can I rely on seaweed, fermented foods or soil?
Spirulina, nori and tempeh are sometimes suggested as alternatives, but they are not dependable B12 plans. The Vegan Society advises relying on fortified foods or supplements. An occasional measurement of B12 in a plant food does not tell you that your own portion reliably meets your needs. [5]
Growing your own food or buying organic does not replace this requirement. Please keep washing your vegetables. Leaving soil on food is not a reliable way to get B12, and it is not something I would recommend trying. The fact that microorganisms make the vitamin does not make dirty food a suitable source. [1]
What if I choose organic or homemade plant milk?
Choose a plant drink you enjoy that fits your budget. Affordable non-organic options are welcome, and you can plan a reliable B12 source alongside whichever drink you choose.
The B12 detail is worth checking: UK plant drinks labelled organic are not allowed to be fortified with nutrients. A homemade drink made from nuts or oats and water also cannot be counted as a reliable B12 source. If these are the drinks you enjoy, plan your B12 separately through a suitable supplement or other reliably fortified foods. [6] [5]
A non-organic fortified drink is another useful option if it suits your budget and preferences. Read the label for B12 specifically; added calcium does not mean B12 has also been added. Fortification varies considerably between plant drinks. My plant milk guide explains the other nutrients to consider. [6]
How much B12 should I take?
The UK reference intake for adults aged 19 to 64 is about 1.5 micrograms a day. This is a dietary requirement, not a once-daily supplement instruction. A microgram is a tiny unit, written as mcg or µg; 1,000 micrograms equals 1 milligram. [3]
Your body absorbs a smaller proportion of B12 from larger supplement doses. That helps explain why a tablet can contain far more than the daily food requirement. Dividing a weekly tablet by seven does not make it equivalent to taking that amount every day. [2]
One plant-based clinician's suggested routine
For adults under 65, Dr Greger suggests cyanocobalamin at 50 micrograms daily, or at least 2,000 micrograms once a week. These are alternative schedules. They are general nutrition recommendations, and should not be used to work out treatment for a suspected or diagnosed deficiency. [4]
Other organisations use different planning figures. The Vegan Society describes a daily supplement of at least 10 micrograms, or at least 2,000 micrograms weekly, as alternatives to a carefully planned fortified-food intake. Follow a complete schedule from a reliable source rather than mixing the dose from one with the timing from another. [5]
If the different numbers leave you unsure, take the product to a pharmacist or registered dietitian. Ask, “Does this amount and schedule suit me?” That is more useful than buying several products and hoping they add up.
Get advice tailored to you if you are pregnant or breastfeeding, choosing a supplement for a child, over 65, have an absorption problem or already receive B12 treatment. The adult routine above should not be assumed to fit these situations. NutritionFacts.org gives separate older-adult advice, and the Vegan Society has guidance for different life stages. [4] [1]
Which supplement form should I choose?
Cyanocobalamin is a well-researched option recommended by the Vegan Society. Your body converts it into the active forms it uses. Seeing “methylcobalamin” or “active” on another label does not establish that the product will work better for you. [1]
The NIH evidence summary does not identify better absorption from one supplemental form of B12, and finds no demonstrated effectiveness advantage for tablets dissolved under the tongue over ordinary oral supplements. Choose a suitable product you can take consistently; a more elaborate format does not automatically offer more benefit. [2]
Check the B12 amount per tablet or serving, the suggested frequency and whether the ingredients suit you. If you already take a multivitamin, include that in the conversation with your pharmacist. Buying a separate B12 product may or may not be necessary depending on what your existing product provides.
If you enjoy looking more closely at the different forms, Kamath and Pemminati's 2017 letter discusses methylcobalamin and asks for better controlled comparisons. It is a useful discussion of the evidence gaps, rather than a trial showing that one form is best. I would keep that in mind when comparing a supplement's claims with its price. [12]
What does the research show?
A small randomised trial by Cristian Del Bo' and colleagues followed 40 vegans and vegetarians with marginal B12 deficiency for 12 weeks. It compared sublingual B12, dissolved under the tongue, at 50 micrograms daily with 2,000 micrograms once weekly. Both groups improved their B12 blood concentrations and related metabolic markers. [7]
The authors reported that:
“both supplements were able to restore adequate serum concentrations of vitamin B12”
Del Bo' and colleagues, Clinical Nutrition [7]
That is useful evidence about these schedules in the people studied. However, this was a small, short trial of marginal deficiency. It does not establish treatment for severe deficiency or nerve symptoms, nor prove that taking B12 under the tongue works better than swallowing a tablet. Both groups used the sublingual route, so that comparison was not tested. [7]
Where can I read more about B12 and the nervous system?
Markle's 1996 review explains B12 biology and why absorption problems can cause deficiency even when someone eats B12-containing foods. It is useful background, although testing has moved on since it was published. The current NICE guidance linked here is the source to use for today's assessment and treatment advice. [11] [9]
For a closer look at specialist questions, Spence's 2016 narrative review discusses B12 deficiency, blood markers, cognition and stroke. Tanaka's 2013 review explores methylcobalamin and nerve disorders; an English abstract is available for that Japanese-language paper. These reviews explain areas researchers have investigated. They do not establish that taking extra B12 prevents dementia or stroke, or that nerve symptoms should be treated without assessment. [13] [14]
How would I know if my B12 is low?
Possible symptoms include unusual tiredness, weakness, pins and needles, a sore tongue, or problems with memory and concentration. Some people have vision changes. These symptoms can have other causes, so they are reasons to get assessed rather than diagnose yourself from an article. B12 deficiency can also occur without anaemia. [8] [9]
Contact your GP if you think you may be deficient. Seek prompt advice for new numbness, difficulty walking or balance problems, or vision changes. Some nervous-system problems can become permanent if deficiency is left untreated; do not wait for a routine supplement to resolve them. [8] [9]
Can people who eat meat be deficient too?
Yes. B12 deficiency can involve absorption problems as well as dietary intake. Causes and risk factors include autoimmune stomach disease, coeliac disease, some stomach or bowel operations, and medicines such as metformin or proton pump inhibitors. Tell your clinician about your diet and medicines; do not stop prescribed medicines yourself. [9]
What happens at a B12 blood test?
A clinician may start with total or active B12, depending on your circumstances. If a result is uncertain and you have symptoms, they may request another test such as methylmalonic acid, often shortened to MMA. Tell them exactly which supplements you take and their doses, because these can affect the results. Do not stop prescribed treatment or delay urgent care to arrange a test. [9]
Will I need tablets or injections?
Treatment depends on the cause and your symptoms. A clinician may prescribe oral B12 or injections; hydroxocobalamin is commonly used for injections in the UK. Some people need ongoing treatment. Follow the plan you are given rather than replacing it with a general supplement schedule from a website. [10]
Keep a note of symptoms you want to discuss and bring your supplement packaging to appointments. If remembering everything feels difficult, write down your questions beforehand or ask someone to come with you.
Making B12 part of everyday life
Planning helps me with food, whether I am shopping for the week or batch cooking for busy days. I would use the same approach here: decide how you will cover B12, then give that plan a place in your routine.
- Check the label on the foods or supplement you intend to rely on.
- Write down the amount and frequency, especially if you choose a weekly schedule.
- Set a reminder and arrange a refill before the pack runs out.
- Recheck your plan when you change brands or switch from fortified to unfortified drinks.
You do not have to solve every nutrition question in one afternoon. Start with this one manageable job, then use the balanced plant-based diet guide to think about the rest of your meals.
I feel well. Do I still need a reliable source?
Yes. With adequate stores, deficiency can take years to develop. Feeling well today does not establish that your ongoing intake is sufficient. Make a B12 plan when you change your diet, rather than waiting for symptoms. [4]
Does needing a supplement mean I have done something wrong?
No. Fortified foods and supplements are the recognised reliable sources for a fully plant-based diet. [1] You can enjoy cooking from scratch and still make use of them. I want you to feel confident asking questions and finding an approach that works in your own kitchen, within your budget.
