Vitamin B12 on a Plant-Based Diet!

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Hello my lovelies!

I have for so long been meaning to share with you more of the library of nutrition information that I have squared away in my brain... Although all of this time away from studies I wonder if its evaporating ;) ... just kidding... No but seriously, I asked you guys what kinds of content you want to see more of and plant based nutrition was a really popular topic and one that I feel really passionate about sharing with you, because I know that knowledge is powerful. It will help you guys to understand why you are choosing this lifestyle! So, first up, I'm going to share some information about Vitamin B12, because this little guy is important in a big way!

I am sure if you follow a plant based diet you have heard of this vitamin, surely someone has told you to make sure you are getting enough Vitamin B12 or supplementing it. But do you understand why it is so necessary and how you can get enough? This is a super important nutrient for plant based diets and I touch briefly on the vitamin in the intro of my cookbook, 'Elsa's Wholesome Life'. I'd like to elaborate more on it here, as well as share with you some really interesting literature I recently came across! But first, lets start at the beginning.... 


Vitamin B12, what is it!

Vitamin B12 (also sometimes called cyanocobalamin or methylcobalamin) is a water soluble vitamin that we must obtain from our food. It is called an “essential nutrient” because our body cannot make it metabolically (unlike some other nutrients). It is made by some types of bacteria both aerobically (with oxygen) and anaerobically (without oxygen).

Biochemical Structure of Vitamin B12 - this brings me back to University days! 

Biochemical Structure of Vitamin B12 - this brings me back to University days! 


Vitamin B12 is important because?
  1. It plays an important role in red blood cell formation - maintains and REPAIRS our red blood cells (which are important as they carry oxygen around our bodies).
  2. It helps to protect our NEURONS from damage and conduct signals in the nervous system. We have something called a “myelin sheath” that protectively wraps around our neurons. Vitamin B12 is required to create that myelin sheath.
  3. Vitamin B12 works with folate to synthesise our DNA.
  4. It helps to break down protein and fat so that our bodies can use these sources as energy!

Early symptoms of vitamin B12 deficiency include constipation, loss of appetite, and weight loss but once symptoms escalate, they can include neurological changes, such as numbness and tingling in the hands and feet. When someone has an extreme B12 deficiency, they can actually develop potentially irreversible and severe neurological disorders (damage to the nervous system and brain - such as psychosis, mania and dementia.) So as you can see, its a really important nutrient and should be taken seriously. 




Okay, so where is dietary Vitamin B12 found? 

Naturally, Vitamin B12 is created by bacteria such as in the gut of humans and animals... Unfortunately for us humans, its produced in the colon, which means its too far down the digestive tract to be absorbable. Our bodies release Intrinsic Factor (IF) from the stomach which bind to Vitamin B12 in order for it to be absorbed in the ileum and transported to the liver. 

But wait... How are the animals that humans eat, getting their B12? Ruminants like cows and sheep are able to absorb it straight from their gut, some even eat their own poop! However with changes to farming methods in recent years, livestock too are becoming Vitamin B12 deficient and needing to be supplemented!

Traces of vitamin B12 can also be found in plant foods via contamination with soil. Some plant based foods are now fortified with Vitamin B12- I will discuss this more soon. 

Major dietary sources of Vitamin B12 are all derived from animal based foods, so it makes sense that vegans are going to have a hard time getting enough Vitamin B12 right.. 

Oh and there is plenty of conditions that can also affect our bodies ability to absorb Vitamin B12. Such as pernicious anaemia- an autoimmune condition that attacks those cells in the stomach that produce IF, a protein that is needed to binding and absorption of B12.

Image source:  @jasminedowling

Image source: @jasminedowling


How much Vitamin B12 do we require?

The recommended daily intake (RDI) for adults (>18 years old) in Australia for Vitamin B12 is 2.4 micrograms per day. Slightly more for both pregnant and lactating women (2.6 and 2.8 micrograms respectively). There is no Upper Limit to how much B12 you can safely consume in your diet as our bodies have an ability to slow down absorption rates of Vitamin B12 when we reach adequate amounts. 

To give you an idea: 1 cup of cow milk contains ~1.1 microgram, 100g raw red meat contains ~2.8 micrograms (more than your RDI). Cooking of animal products does slightly reduce the content. 

If you are sitting here reading this thinking... "I follow a predominantly or exclusively plant based diet and am worried I am not getting enough Vitamin B12, what should I do?!!"

My advice would be to first, see your GP and have a blood test to check your Vitamin B12 levels. Routine blood tests (6 monthly) is an important health precaution every body should take to ensure you are not deficient or overloaded in any nutrient. It is important to get a qualified health professional to review your blood test results (a Doctor or Dietitian/Nutritionist). This is because solely looking at your B12 result on a blood test doesn’t necessarily indicate you are low. A high amount of folate in your blood can actually mask a B12 deficiency. Your health professional will know how to accurately interpret your results. Values of less than 200 pg/mL are a possible sign of a Vitamin B12 deficiency. However, deficiency should be confirmed by checking the level of a substance in the blood called methylmalonic acid (MMA). A high level indicates a true B12 deficiency.


So, you've been told your Vitamin B12 deficient... (by a qualified health professional)

If your levels of Vitamin B12 are below the recommended range and you follow a plant based diet (do not consume dairy or eggs) taking a Vitamin B12 supplement is recommended. Of course, I believe you should tackle all health issues with diet first, however as this deficiency potentially dangerous, supplementation/an injection to get yourself back into the healthy range is a good idea. Have your bloods re-checked to confirm this. 


Maintaining an adequate Vitamin B12 range on a plant based diet.

If you would like to maintain your Vitamin B12 using a plant based diet alone, proper planning is required or at least a generous amount of certain foods regularly. There are I guess 3 rough categories for ways in which you may get Vitamin B12 from a plant based diet. 


1. Plant based foods containing small amounts of Vitamin B12

HANG ON! I thought there were no plant-based sources of Vitamin B12...?? Well, up until about 2 months ago, I was under the impression that Vitamin B12 could not be obtained from ANY plant food too. Ground breaking research has revealed that there are some plant based foods that contain active Vitamin B12. It's still VERY early days but this could be a really exciting finding for the plant based diet. I'm going to try dive into the studies and summarise what I found as best as possible (all my sources will also be linked below).

Research suggests that fermented soy products (Tempeh), certain forms of algae, seaweed (Nori sheets!) and specific mushrooms (eg. Shiitake) have significant amounts of Vitamin B12. BUTTTT proper trials to prove their ability to improve vitamin B12 (and MMA- the indicator of B12 deficiency) have not yet been done, most research has either been confounded/floored or proven not to improve levels (hence may not actually be active forms). I'll be keeping my eye out for more research in the area! I'll go into a bit more info about each of these plant foods from what I have researched. 

Also, soil containing manure and bacteria used to grow plants CAN provide trace amounts of the nutrients into vegetables that grow via ground roots. HOWEVER, this is trace amounts only so not enough to be considered reliable. 


While soybeans (and tofu) themselves do not contain considerable amounts of Vitamin B12, its product, Tempeh, can! The process of producing Tempeh involves fermentation of the soybeans, and fermentation is a process involving BACTERIA, remember, Vitamin B12 is produced by certain types of bacteria (hooray for bacteria!!). Some sources suggest Tempeh may contain 0.7-8.0 micrograms of Vitamin B12 per 100g (varies greatly based on that degree of fermentation and. bacteria type!). The research on this is still very much undecided. One source suggests that Tempeh produced in tropical places like Indonesia does contain the bacteria required to produce active B12, while Tempeh in the USA and Europe doesn't. - Take home message: do not rely on Tempeh as a sole source of B12 until we have more information. 


Various batches of nori were found to contain significant amounts of the B12 analogue (types of B12) there is a good chance that some of this B12 is active. Unfortunately, while some types of Nori may contain considerable active B12, an improvement (lowering) of MMA levels have not yet been shown through studies in humans consuming nori, so it may contain active B12 its unable to lower MMA, which is the true/accurate measure of B12 deficiency. Algae deserves further attention to see if it can consistently lower MMA levels in humans.


Research from the University of Western Sydney found that mushrooms of all types contained variable amounts of active/bio-available B12 (same form found in animal products... hence absorbable). It varies from crop to crop and the majority was found in the surface/outer layer (skin). This is most likely due to bacterial fermentation on the mushroom surface but more likely due to soil/compost contamination. 

How much? The amount of B12 in mushrooms varies from crop to crop. One serve will provide about 2-4% of the RDI. Mushrooms studied and believed to contain the highest amounts include: the Black Trumpet and Golden Chanterelle mushrooms. Both of these mushrooms I have never seen available, hence may not be a reliable source. Shiitake mushrooms have also been researched and believed to contain good amounts of the active Vitamin B12, however it would require 50g of dried shiitake mushroom daily to meet the requirement which is not considered achievable or safe and studies are yet to show its ability to increase levels of B12 in humans (and lower MMA). 

While the amount of B12 in the average serve of mushrooms is not much, regular intake can help/assist in obtaining your requirement. Also, importantly, you should avoid peeling the outer skin off the mushrooms. Do not rely solely on mushrooms but consider that they MAY assist. 

Soo, who else is confused? Don't worry, I have studied nutrition for 4 years and I am still trying to understand all the non-sense I read online! Some sources will tell you Spirulina, Chlorella, Nori, Tempeh, Mushrooms and organic produce will give you all the B12 you need, but as we can see its much more complicated than that! and we simply need good quality studies to be done! 


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2. Plant-based foods fortified with Vitamin B12

So, if you are looking to achieve your B12 requirement from diet alone, the only reliable source is foods that have been fortified with it (that means B12 has been added). Fortunately, nowdays there are a wide range of foods that are fortified with active B12 in order to help us reach our requirements. The best approach to doing this is to eat foods that are fortified with vitamin B12 frequently as vitamin B12 is absorbed in small and varying quantities e.g. 1 microgram, 3 times daily. 

Here is some commonly fortified plant based foods:

- Plant milks

- Soy products

- Nutritional yeast

- Breakfast cereals (beware of the sugar content of some of these though!)

- Prepackaged protein alternatives (such as veggie sausages and veggie patties)

Be sure to check the labels to see if they are fortified with vitamin B12.

I have been trying to research the best fortified plant milk for B12 and not having much luck, many fortify with Calcium however. So Good Soy Milk contains 1 microgram of B12 per 250mL, however theres also 5g of sugar in the cup plus plenty of other stuff you don't want in your soy milk (plus its made from soy protein rather than whole soy beans ~ AKA processed!).  

Personally, I consume fortified nutritional yeast flakes, almost daily, sometimes twice daily, to help support my vitamin B12 intake (along with a supplement). For example: Bob's Red Mill Nutritional Yeast Flakes contains 5.8 micrograms per 5 grams (maybe 2 tbsp's- I need to measure this!), which is more than your daily requirement. I get lots of questions in my DM's about Nutritional Yeast flakes (how to eat them, what they taste like). They are a savoury, almost cheesy flavour, and taste absolutely delicious sprinkled on veggies, blended into soups, mixed into sauces/nut cheeses, or baked into veggie patties. Give it a try! I use them in loads of recipes inside my cookbook! 


3. Supplements 

While I advocate for a food first approach, unfortunately, supplementation is the most widely researched and backed-by-evidence approach to achieving adequate Vitamin B12. It has not been found to be harmful to health, so if you would prefer a quick and simple way to achieve your B12 intake, then go for it!

There are so many of these out there on the market today. Oral supplements, lozenges, oral sprays and even gels that you topically place on your skin (there is limited evidence for the effectiveness of skin gels though!).

I recommend taking an oral supplement (i.e. oral spray, tablet, lozenges). However, it is best to get one that is JUST solely for Vitamin B12. Many multivitamin formulations and vitamin B-complexes include Vitamin B12. However, the amount of actual B12 in these mixed supplements is variable. Even though the recommended intake of B12 is only 2.4 micrograms a day, many supplements provide 500-1000 micrograms . This is because there are such large variations in absorption rates among individuals. Don't be too concerned, remember- our bodies won't be able to absorb that big of a dose unless its injected.

It is important to note that the body is only able to absorb a small amount of Vitamin B12 at any one time. So you should supplement with small amounts/frequent daily oral doses, instead of infrequent large oral doses. I personally use a liquid iron supplement that contains vitamin B12 (FabIron) but this contains only 1.4 micrograms per 10mL, so not quite enough to reach my daily requirement, hence I pair with daily nutritional yeast flakes AND a specific B12 supplement called Perform by BEAR Ltd. which contains 500mcg and is enough to keep my levels normal and healthy. As always, speak to your Doctor, Dietitian or Naturopath about which supplement they recommend for you. 


SO does the fact that a plant based diet doesn't provide adequate B12 in-fact make it inadequate? 

My answer... NO. Most definitely not! Think about all those unhealthy nutrients you are avoiding/reducing by following a plant-based diet (e.g. cholesterol and saturated fats!) and all the amazing other properties you will be getting from a plant based diet. Supplementation with B12 is safe AND effective. 


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Well, that concludes this blog post about Vitamin B12!

I would LOVE to hear what you think of this blog post! too much information or did this help clear up the issues surrounding Vitamin B12? Happy to try answer any of your questions in the comments section below!

However for individual and personalised nutrition information I highly recommend you see a qualified dietitian, specialising in plant based nutrition. One of my best friends and fellow dietitans, Emily from Sprout Journal, consults from her home in Melbourne, Australia or online via Skype, and I highly recommend her! Here is the link to her nutrition services!

Well... Thanks for reading!

Elsa, xx 



Part written by my dear friend and fellow dietitian, Emily Burch from Sprout Journal

Other sources:

Koyyalamudi SR, Jeong SC, Cho KY, Pang G. Vitamin B12 is the active corrinoid produced in cultivated white button mushrooms (Agaricus bisporus). J Agricultural & Food Chemistry 2009; 57 (14): 6327-6333

Article available via:

Watanabe F, Yabuta Y, Bito T, Teng F. Vitamin B12-Containing Plant Food Sources for Vegetarians. Nutrients. 2014;6(5):1861-1873. doi:10.3390/nu6051861.

Article available via: