What Is Vitamin B12? Plus How You Can Get It On A Plant-Based Diet?

With so many more people on plant-based diets and the advancement of medicine, we are hearing about the vitamin B12 more and more. Personally I had not heard of B12 until I went vegetarian, and for most people, it is the same. Although I would like to point out even those who eat meat can still be deficient in B12. So, where ever you are in your plant-based journey it is important to make sure you are getting enough.

This guide is long, but I have tried to make it your one-stop-shop for everything B12 related. So even if you don't read it all today save it somewhere so you can come back to it any time you need.

The Importance of B12

B12 is a vitamin that has numerous functions in our body, I could give you the scientific mumbo jumbo like in the image above, but unless you are a doctor you will have no idea what it means. So let me give you the simple AF version.

All B vitamins are important, without enough of them, we can begin to feel sluggish, depressed, have little energy and find it difficult to concentrate and focus. In some extreme cases not have enough can also cause nervous system damage or anemia.

Unfortunately on a plant-based diet, this is the one vitamin that is hard to get through whole foods. You will most likely need to go out of your way to make sure that you are eating foods that are fortified in B12 or have a supplement.

Whilst this may sound like a pain, remember that without enough B12 in your system, the damages you experience can range from heart issues to complications with pregnancies. Which is why this is such an important vitamin.

What are the functions of B12?

Now that we know why B12 is so important let's talk about its actual functions in the body. One of the most important functions is its role in the formation of red blood cells. 'Pernicious anaemia' occurs when not enough B12 is taken into the body. In this condition, the quality of new red blood cells formed is poor, which then decreases overall health and function. Other functions include keeping your nerves healthy, supporting the production of DNA, as well as maintaining normal brain function.

Other benefits of B12 include its role in maintaining and increasing the energy level in the human body. Which is why, when someone has a B12 injection they feel so energetic afterwards.

Where does B12 come from?

There is a lot of confusion and myths about where B12 comes from. Many people believe that B12 is made by animals. Therefore if we don't eat animal products we can't get this important vitamin. However, this is far from the truth, just like us animal can't make B12.

So where does B12 come from? Well B12 is synthesised by bacteria and is therefore found in areas of bacterial growth, namely dirt and soil.

Humans used to get their B12 from eating plants that still have bits of soil on them. However, in today's world where we understandably wash our fruits and veggies, we are unable to consume the dirt or proper levels of B12. This is where B12 supplements and fortified foods come in.

But here is where it can get confusing. If we are taking supplements then isn't our diet unnatural? But what people don't realise is that whilst yes animals in the wild get their B12 from eating plants that of course are unwashed. Majority of animals that humans eat are actually also getting a supplement. Because even though many animal products say "organic", "free-range" and "grass-fed" they are still in some sort of caged area and are given their food instead of naturally obtaining it from the ground.

Let's say though that the animals naturally get it from their food you would still be eating products that have a lot of other nasty stuff like fat, cholesterol, toxins, hormones and antibiotics! So is it really any more natural getting B12 from animals than it is from a supplement or fortified foods?

How much vitamin B12 do you need?

There is no one answer for this sadly. It depends on things like your age, eating habits, medical conditions and even what medications you take.

Here is a rough guide of how much B12 you need measuring in micrograms (mcg):

  • Infants up to age 6 months: 0.4 mcg

  • Babies age 7-12 months: 0.5 mcg

  • Children age 1-3 years: 0.9 mcg

  • Kids age 4-8 years: 1.2 mcg

  • Children age 9-13 years: 1.8 mcg

  • Teens age 14-18: 2.4 mcg (2.6 mcg per day if pregnant and 2.8 mcg per day if breastfeeding)

  • Adults: 2.4 mcg (2.6 mcg per day if pregnant and 2.8 mcg per day if breastfeeding)

Should I get my vitamin B12 levels tested?

The short answer is yes! But not because you are plant-based. I believe everyone should get their B12 tested once in a while. After all, 2% of people do not absorb B12 well. So even if you were eating animal products, your B12 could still be on the low side.

If you want to know if you are one of the 2% that doesn't absorb B12 well there are a few ways to do it. First, you will need to have a reliable source of B12 for at least a few weeks before your levels are tested. If it is then low when tested it could be because you aren't absorbing it well. However, there are other specific tests that directly measure B12 absorption if you are worried.

When you get your B12 levels checked, keep in mind that seaweed can falsely inflate B12 levels. This is because many types of seaweed contain a variety of inactive B12 analogues. And at the moment methods for determining B12 levels can not distinguish between B12 and some inactive B12 analogues. So if you are someone who eats lots of sushi you may have serum B12 levels well above normal, but much of it could be inactive B12 analogues.

A different type of B12 test

Another way you can check your B12 level is by checking your blood homocysteine level. However, keep in mind it is not a direct measure of the vitamin B12 because it can also be affected by folate and vitamin B6. In saying that though homocysteine is the only known product of early B12 depletion that is thought to cause harm. For that reason, it is a really important marker for B12 status.

If you are worried about your B12 levels you can ask your doctor to test your blood for B12 and/or homocysteine level. However, if you know you are getting the recommended amount for B12 every day and don't have any symptoms, you don't need to rush to make an appointment. I just ask to get my levels tested every two years or so to make sure I am still on top of everything.

What level should your B12 be when tested?

This is a question a lot of people want to know, and whilst your doctor will tell you if its low or not I like that people want to take charge of their own health. Based on data from the National Health and Nutrition Examination Survey (NHANES) it was determined that 300 pmol/l (405 pg/ml) was the minimum level required to prevent elevated homocysteine. Which can be achieved by following the B12 recommendations in this article.

What happens if you don't get enough B12?

Okay, so we have talked about the importance of B12, how much B12 you need and how to get it tested. But what happens if you do have a B12 deficiency? Some of the common symptoms are:

  • Constant fatigue

  • Constipation

  • Little to no appetite

  • Nausea

  • Unplanned weight loss

  • Numbness and tingling sensations

  • Dizziness

  • Soreness of the mouth and tongue

  • Problems with balance

  • Loss of menstruation

As I mentioned about B12 protects your nervous system and without adequate amounts of it, permanent damage can occur. This can include blindness, deafness and even dementia. So let's make sure we keep our B12 levels up!

Sources of B12

These days it is easier than ever to get B12. In the following section, I will be talking about different ways you can get that all-important B12.

B12 fortified foods

The first way is to get your much-needed B12 through fortified foods. These can include cereals, plant-based milk, meat alternatives, nutritional yeast, protein powder and even chewing gum. Personally I get a good dose of B12 just from my breakfast by including my protein powder and almond milk (both fortified in B12) into my smoothie.

Look at foods you are already buying and see if they are already fortified with B12 or if you can swap them for ones that are. Depending on how many of these foods you have each day, you may need to mix in another method of getting B12 to make sure you are getting adequate amounts. Especially seeing as the downside of these foods is that they aren't always the healthiest. Not only do they add in the B12, but they could be adding in sugar, salt and other unwanted additives.

B12 supplements

Taking supplements is often the easiest and most recommended way for getting enough B12. You can get tablets that need to be taken once a day or ones you only need to take once a week. If tablets aren't your style you can get the supplement in spray form. you just spray it on your tongue once a day.

Other companies have a powder version of the supplement (usually as part of a multivitamin) which you can add into your smoothies, salad dressing, curries or even in your baking. They usually have a neutral taste so you won't taste it, meaning you could even just mix it into a glass of water.

However, keep in mind not all vitamin B12 supplements are the same. So don't just pick up the first one you see. Take a minute to consider which one will work best for you.

The first thing to consider is some include animal-based fillers, which make them unsuitable for those of you avoiding all animal products. However, that is not the only thing that might be added to the supplements. So do some research and check nutrition labels.

Keep in mind that it is generally believed that large doses of vitamin B12 are not harmful. However, a few cases or rosacea and acneiform brought on by vitamin B12 treatment have been reported. So if you do notice a rash after taking a large dose of vitamin B12, discontinue use and see your doctor. You will most likely need to take smaller doses of B12 at a time and fortified foods might be a better option.

B12 injections

Doctors usually only recommend B12 injections if you have really low B12. Once they are back up to a "normal" range they will usually then recommend taking a supplement. However, I do know a few people who just opt to just have a B12 injection every month or two. Although I wouldn't recommend this as it can be quite costly as you are paying for the medicine (the injection) and then for the appointment to get it.

If you want a low fuss option, it would be better to get a supplement that you only need to take once a week.

I heard you can get B12 from nori, spirulina, barley grass, raw foods...

Whilst many people believe this, sadly it isn't true. Scientific research has shown that plant-based sources of vitamin B12 to be inadequate. Relying purely on them is dangerous. Instead, take supplements or eat B12 fortified foods.

B12 absorption

Just like with iron, there are foods that you can eat to help your body absorb B12 better. So to make sure you are absorbing B12 as easily as possible make sure you are having some iron and vitamin C at the same time.


I highly recommend saving this article as I know it is a lot to process at once and you may need to re-read it a couple of times. However, these are the key takeaways:

  • B12 is needed for your red blood cells and nervous system

  • As an adult over 18 years of age, you want to be having 2.4mcg of the vitamin B12 each day.

  • You can get B12 through fortified foods, supplements or injections.

  • It is best to have B12 with iron and vitamin C to help absorption.

What you should do now

  1. I have been where you are and I have women all over the world (just like you) transition to eating a plant-based diet. If you are looking for a guide to help you find the healthiest way to eat, this FREE 7 Step Guide to Healthy Eating is a great place to start.

  2. If you are interested in weight loss, download this fantastic FREE Mini Weight Loss Guide.

  3. If you would like to learn more about losing weight on a plant-based diet go to the Where My Footsteps Go Blog, where there are heaps of articles.

  4. And finally, if you want to join the Where My Footsteps Go Community click here.