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Vegan Essentials – Vitamin B12

Vitamin B12

Vitamin B12 – it’s complicated

A blog about vitamin B12 could be very short, or really rather long and quite complicated.

The short version would go like this: “It’s important for vegans and vegetarians to supplement with B12.”

The longer version would explain about how you can get it from some fortified vegan foods – nutritional yeast being perhaps the best-known – but that regular supplementation is still definitely the way to go. It would have to touch on how these days most farmed animals have to be supplemented with B12 anyway. And that it’s simply not true to say that it’s just vegans or vegetarians who are at risk of B12 deficiency.

I’d also want to tell you that a simple blood test that measures your serum level of B12 won’t necessarily tell you if your body is absorbing it effectively at a cellular level (a better test would be for levels of a protein called homocysteine); and that common medications for indigestion and diabetes could be putting you at risk of B12 deficiency whether you are vegan or not.

Certain kinds of gastric surgery, excess alcohol consumption, ageing and autoimmune disease can also up your risk. And then there are genetic variations which mean some of us (me included!) inherit an inability to absorb B12 very efficiently. So recommended daily intakes will vary from person to person. (As a general guide, see the recommendations on the Vegan Society’s website.)

A lack of B12 can cause a huge range of symptoms including fatigue and depression, some kinds of anaemia, dizziness, tingling in the fingers (or toes) and memory loss and confusion that can be misdiagnosed as dementia.

Vitamin B12 is essential for healthy nerve function and it plays a key role in a vital chemical function in our bodies called ‘methylation’. It is what’s known as a ‘methyl group donor’. If there isn’t enough B12, then levels of homocysteine – which I mentioned earlier – can rise, and that in turn leads to an increased risk for a range of pretty serious health problems from infertility and heart disease to stroke and DVT. It’s also worth noting that B12 alone may not lower elevated homocysteine – various combinations of other nutrients may be needed. Homocysteine is definitely a blog on its own…

And as if all that weren’t enough to take in, there are no fewer than four different types of B12 you could take in supplemental form. There’s cyanocobalamin, hydroxycobalamin, adenosylcobalamin and methylcobalamin. Food sources like meat, poultry and eggs contain B12 mainly in the forms of adenosylcobalamin and hydroxycobalamin. Cyanocobalamin is the one you’ll find most often in supplements but it has to undergo conversion to an active form in the body before it’s any use to us. Supplemental methylcobalamin is very popular these days – but it may not be right for everyone.

I told you it was complicated.

As a good starting point, I generally recommend B12 supplements in a sublingual (under the tongue) or liquid form to try and maximise absorption. Personally I take a vegan hydroxycobalamin.

I would then look to see if there were any digestive problems or other symptoms that might point to a possible B12 deficiency. Homocysteine testing might be another sensible option. If homocysteine is high, then B12 may well be being poorly absorbed even if a serum blood test shows you’re within the ‘normal’ range.

If you have any concerns, there’s plenty of information out there and I’ve put some reliable, well-referenced links below. The Vegan Society’s coverage is particularly helpful and comprehensive and Sally Pacholok’s book is very clear and well written.

Further reading
‘Could it be B12? An epidemic of misdiagnoses’ (paperback) by Sally M Pacholok and Jeffery Stuart

I also used one of my favourite textbooks, ‘Clinical Nutrition: A Functional Approach’ (Liska et al) for background research for this article.


This article was written by Claire Hider, registered Nutritional Therapist. Claire is a regular contributor here at The Tartan Carrot. To find out more about Claire Hider, please click the button below to visit her website:

Claire Hider - Registered Nutritional Therapist