Vegan B12 Deficiency – Symptoms and How to Prevent


The only thing that you can’t get from whole foods on a typical vegan diet is vitamin B12.

Considering that a decent portion of the general population is already B12 deficient, it’s even worse for us vegans.

B12 is used by the body to make and maintain important things like red blood cells, nerves, and DNA (among others).

It’s very important.

If you’re significantly deficient in B12, you may notice symptoms like:

  • Tingling and numbness in limbs.
  • Balance issues.
  • Anemia.
  • General “brain fog”.
  • Memory problems.
  • Fatigue and weakness.

Many people who have had a B12 deficiency start to take supplements, and all of a sudden feel like their mind is clearer.

It can also lead to even more serious health conditions if the deficiency is bad enough and lasts for an extended period.

B12 is even more important for pregnant women, as a B12 deficiency can cause life-threatening complications in newborns.

There’s quite a few studies that show that vegans are much more likely to be B12 deficient.

I’ll go over those, along with what you can do to easily prevent B12 deficiency as a vegan.

If you do notice any of those symptoms for an extended period, please go see a doctor. There are other potential causes (like genetic) of B12 deficiency other than diet alone. You don’t want to try and treat it with a diet change if that’s not the cause, it won’t help you.

The Science Linking Vegans to B12 Deficiency

I’ll try to keep this as simple and brief as possible.

First, researchers detect B12 deficiency by measuring homocysteine levels, which is related to B12 functions. If you have a B12 deficiency, your homocysteine levels will rise.

For example, in one specific study, they found that hyperhomocysteinemia (those high levels) in 53.3% of vegetarians, and only 10.3% of the control group (omnivores).

There are several more studies that did a similar thing, looking at vegetarians and vegans around the world. Summing all these up, about 50-70% of vegans and vegetarians are B12 deficient.

Even though it’s easy to prevent, it’s very common in vegans.

How to Easily Prevent Vitamin B12 Deficiency

Let’s start with how much vitamin B12 you need.

The recommended daily allowance (RDA) of vitamin B12 is 2.4 mcg. That’s micrograms, which is equivalent to 0.0024 grams.

So you don’t need much.

Additionally, your body can store 2,000-4,000 mcg, so if you’re coming from a meat-eating diet, B12 deficiency isn’t an immediate worry.

But at some point, you will need to find a way to get B12 in your diet. You have 2 main options:

  1. Supplements
  2. Fortified foods

Either will work, a combination is easiest and safest.

Which Vitamin B12 Supplements Are Vegan, and How Much Do You Need?

I’ve already written about the best vegan vitamin B12 supplements that you can see at any time.

In one study, people with B12 deficiency were given daily supplements of B12, and their serum levels were healthy within 12 weeks.

Supplements usually have about 1,000 mcg of B12 per serving (pill or lozenge), which is about 400 times what you need in a day.

You only absorb about 1% of that B12 at most, which is 10 mcg, which is still well over the RDA.

Typically you need to eat a pill anywhere from daily to once a week, it depends on the supplement and its dose.

Can You Get Enough B12 From Fortified Foods

Many packaged vegan foods are fortified with vitamins and minerals, and B12 is one of the most common ones.

For example, in a tablespoon of Bob’s Red Mill’s nutritional yeast, there’s 4.4 mcg of B12.

Bob’s Red Mill’s nutritional yeast

Here’s a more detailed look at vegan vitamin B12 food sources, which includes foods like cereal, granola, and non-dairy milks.

Unless you eat a lot of these types of foods, getting your B12 only from them is less reliable and a little risky.

So while it’s up to you, I’d recommend a combination of fortified foods and a good B12 supplement to be on the safe side.

If you do this, there’s a slim chance that you’ll ever have a vitamin B12 deficiency, and it’s not hard to do or expensive.

About the author

Dale Cudmore

Your friendly neighborhood vegan from Toronto. Chemical engineer turned semi-professional soccer player and freelance nutrition writer. I've been vegan for years and try to make life easier for others by sharing what I've learned.

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