Do Vegans Need B12? What You Need to Know About Vitamin B12

Yes. Vegans need a reliable source of vitamin B12, either a supplement or foods fortified with it, because plant foods don't naturally contain it. Adults need 2.4 micrograms a day, according to the NIH Office of Dietary Supplements. Vegetarians who eat eggs and dairy get some B12 from those foods, but many still benefit from fortified foods or a supplement. It is one of the few nutrients where a plant-based diet needs a deliberate plan.

Why B12 doesn't come from plants

Vitamin B12 isn't made by plants or animals. It is made by certain bacteria and other microbes. Animals accumulate it in their tissues, either from bacteria in their own digestive systems or from their feed, which is why meat, fish, eggs and dairy contain it. (Many farm animals also get B12, or the cobalt their gut bacteria need to make it, through supplemented feed.)

Plants don't need B12 and don't store it. The NIH notes that plant foods don't naturally contain vitamin B12, which is why strict vegetarians and vegans are listed among the groups at higher risk of falling short. Some foods like seaweed, mushrooms and fermented foods are sometimes claimed to contain B12, but the amounts are unreliable, and some contain inactive forms that the body can't use. They shouldn't be counted on as your source.

This isn't a sign that a plant-based diet is unnatural. It reflects the fact that modern food is very clean, and that B12 is so concentrated in animal products that most people have never had to think about it. For vegans, the answer is simple: take it intentionally.

What B12 does

B12 helps your body make red blood cells and DNA, and it keeps your nerve cells healthy. Without enough, you can develop a type of anemia and, over time, nerve damage. That is why it matters to get it right, and why it is worth taking seriously rather than hoping your diet covers it.

How much you need

The NIH Office of Dietary Supplements gives these Recommended Dietary Allowances:

• Adults: 2.4 mcg per day
• During pregnancy: 2.6 mcg per day
• While breastfeeding: 2.8 mcg per day

Those numbers can look tiny next to the amounts in supplement bottles, which often contain hundreds or even thousands of micrograms. That is because absorption drops sharply at higher doses. The NIH notes that only about 2 percent is absorbed at a 500 mcg dose and about 1.3 percent at 1,000 mcg. So a higher-dose supplement taken less often can still deliver what you need. The NIH also notes no upper limit has been set for B12, as no harm has been linked to high intakes from food or supplements.

Supplements vs fortified foods

There are two practical ways to get B12 on a vegan diet.

Supplements are the most reliable option. B12 comes in several forms, including cyanocobalamin, methylcobalamin, adenosylcobalamin and hydroxocobalamin. You will see a lot of marketing claiming one form is superior, but the NIH says research hasn't shown any form of supplemental B12 to be better than the others. Cyanocobalamin is the most common and usually the cheapest. Many vegan multivitamins also include B12.

Fortified foods include many breakfast cereals, some plant milks, some meat substitutes, and fortified nutritional yeast. If you rely on fortified foods, check the labels to confirm B12 is listed, look at the amount per serving, and make sure you eat them regularly enough to meet your needs. Not every brand of plant milk or nutritional yeast is fortified, so it is easy to assume you are covered when you aren't.

Many people use both: a supplement as the reliable baseline and fortified foods as a bonus. For most, a supplement is the simplest way to stop thinking about it. A registered dietitian or doctor can help you choose a dose and schedule that fits you.

Signs of B12 deficiency

The NIH lists these possible signs of B12 deficiency:

• Feeling tired or weak
• Numbness or tingling in the hands and feet
• Problems with balance
• Depression or confusion
• Poor memory
• A sore tongue or mouth

The tricky part is timing. Your liver stores a large reserve of B12, and the NIH notes that symptoms of deficiency can take several years to appear. So someone who went vegan a year ago might feel fine and assume they don't need a supplement, while their stores are slowly running down. Don't wait for symptoms.

If you notice any of these signs, or you've been eating plant-based for a while without a reliable B12 source, talk to a doctor. A blood test can check your levels, and deficiency is treatable. Nerve damage from a long-term deficiency can be harder to reverse, which is another reason to stay ahead of it.

Vegetarians need to think about it too

B12 isn't only a vegan issue. Eggs and dairy do contain B12, and vegetarians who eat plenty of them may meet their needs. But the NIH notes that vegetarians who eat some animal products are also at higher risk than meat eaters, because their B12 sources are more limited. If you eat dairy and eggs only occasionally, a supplement or fortified foods are worth considering.

Other people at higher risk

Diet isn't the only factor. The NIH lists other groups that may have trouble absorbing B12, including:

• Adults over 50, who may produce less stomach acid
• People with pernicious anemia
• People with celiac disease or Crohn's disease
• People who have had stomach or intestinal surgery, including weight loss surgery

Some medications can also affect B12 levels, including metformin and long-term use of acid-reducing drugs such as proton pump inhibitors. If any of these apply to you, it is worth discussing B12 with your doctor regardless of your diet.

Pregnancy, breastfeeding and kids

B12 matters even more during pregnancy and breastfeeding. The NIH notes that breastfed infants of mothers who eat no animal products may have very limited B12 reserves and can develop deficiency early in life. If you are pregnant, breastfeeding, or raising kids on a plant-based diet, work with a doctor or registered dietitian to make sure everyone has a reliable source.

Building the habit

The easiest way to stay on top of B12 is to tie it to something you already do every day: next to your toothbrush, your coffee, or your phone charger. Most people who struggle with B12 don't disagree that they need it. They just forget.

It helps to think of B12 as part of the same toolkit that makes eating less meat sustainable: a reliable protein plan, a few meals you can cook on autopilot, and a way to get through the moments when a craving hits. Those cravings tend to peak and fade within 10 to 20 minutes. The Spared app is built for that moment: open it instead of the fridge, ride out the craving, and watch it count each one you get through alongside your days and the animals spared.

For more on how your body adjusts after cutting meat, see what happens when you stop eating meat. For the other nutrient people ask about most, see protein without meat.

This article is general information, not medical advice. A doctor or registered dietitian can give you guidance based on your own health.

Common questions

Can you get B12 from plants?

Not reliably. Plant foods don't naturally contain usable B12. Foods like seaweed, mushrooms and fermented products are sometimes promoted as sources, but their B12 content is inconsistent and may include inactive forms. Fortified foods and supplements are the dependable options.

How much B12 should a vegan take?

The adult RDA is 2.4 mcg a day, but supplements often contain much more because absorption is lower at higher doses. Dosing approaches vary, so ask a doctor or registered dietitian what makes sense for you, especially if you are pregnant, breastfeeding, over 50 or taking medications that affect absorption.

Is nutritional yeast a good source of B12?

Only if it is fortified. Many brands of nutritional yeast have B12 added, but some don't. Check the label for B12 and the amount per serving, and keep in mind you need to eat it consistently for it to count.

How long does it take to become B12 deficient after going vegan?

It can take several years, because the body stores a large reserve of B12 in the liver. That delay is why you shouldn't wait for symptoms. Start a reliable source when you change your diet, and ask your doctor about testing if you have concerns.