Be smart, B12

If you follow a plant-based diet, vitamin B12 is probably on your radar – and it should be! This is one nutrient you need to supplement. Here’s why. Article by DFN's Lead Dietitian for South Australia, Deeni Betar-Young APD, first published in Nourish Magazine.

Vitamin B12 supplements: the most important nutrient for vegans and anyone else following a completely or predominantly plant-based diet.

Often flagged as the most important nutrient to be aware of on a plant-based diet, vitamin B12 (also known as cobalamin) is required for normal blood function and neurological health, and deficiency is serious. There are plenty of myths surrounding B12, so let’s learn how to ensure adequate intake. B12 is produced by certain bacteria (not by animals, as some people believe) when in environments containing the mineral cobalt, which makes up part of the structure of vitamin B12. Animal products can be high in B12 because animals obtain it from bacteria in the food (or faeces!) they eat, or are able to synthesise it in their guts.


Historically, traces of soil left on foods grown in nutrient-rich environments and unsanitised drinking water were likely to have been regular sources for early humans. However, this is no longer the case. We now (quite rightly) sanitise our water supply and wash our vegetables thoroughly to avoid ingesting pathogens. Also, in part due to intensive farming practices, soils have been depleted of many nutrients globally. As a result, even farmed animals are commonly given B12 supplements.


Is there B12 in plants?

There have been many claims made about natural plant sources of B12, with certain foods such as seaweed, spirulina, mushrooms, and fermented foods reported to contain it. While some of these foods do in fact contain B12, in most cases this appears to be predominantly in ‘inactive’ forms. These do not fulfil the important functions of ‘active’ forms in the body, and can even block uptake of the active B12! Even where the B12 does appear to be in a form that we can absorb, we’d be hard-pressed to consume enough of that particular food to meet our daily needs. The key message is that none of these foods have been shown to improve the B12 status of humans and therefore cannot be relied upon for adequate B12 intake.

Girl taking a vitamin B12 supplement
There are only two non-animal food sources of vitamin B12: supplements and fortified plant foods

Because B12 is produced by bacteria, some is formed in our bacteria-laden guts (or colons); however, this isn’t able to be absorbed into our bloodstream because B12 absorption occurs higher up in our digestive tract, in the small intestine. As a result, there are only two non-animal food sources of vitamin B12: supplements and fortified plant foods.


Fortified foods are those that have had B12 added to them during processing, like nutritional yeast, certain meat substitutes, and some plant milks. The B12 content of fortified foods can vary considerably between brands and batches. To obtain and absorb enough vitamin B12 from these foods, they need to be consumed at multiple times over the day and often in quantities that exceed standard serving sizes. For this reason, it’s always preferable to also take a supplement rather than relying solely on fortified foods.


So, are omni diets better?

While there’s no denying animal products do contain B12, we can safely say that this limited benefit is outweighed by the costs. This is because animal products come packaged with certain harmful properties, including known cancer-promoting agents, production of TMAO (a significant causal factor in our number one killer, heart disease), saturated fats that promote insulin resistance, inflammation, and numerous other risks including overall increased mortality. By contrast, wholefood plant-based diets are associated with reduced risks of diabetes, heart disease, many cancers, autoimmune diseases, and much more. Further, animal farming promotes antibiotic-resistant infection risks and the emergence of zoonotic diseases that transfer from animals to humans. So, we can safely say it’s preferable to eat a healthy plant-based diet with a cheap and effective B12 supplement than it is to eat animals!

It’s preferable to eat a healthy plant-based diet with a cheap and effective B12 supplement than it is to eat animals

Deficiency isn't just a vegan problem

Older lady with daughter
Anyone over age 50 is in the higher risk category for B12 deficiency