The importance of vitamin B12 (also for vegans)

Gabrielle Koster

Vitamin B12, you’ve either heard quite a lot about it or you don’t know anything about it. And let’s be honest, it’s a very important vitamin. For vegans, but also for carnivores. The vitamin could play a very important role in DNA synthesis, cellular repair processes, blood production and brain function, according to

So, what’s the deal with B12 deficiency’s?

There’s a lot of vitamin B12 warnings for vegans: if you follow a plant based diet, make sure you add vitamin B12 because it’s only found in animal products. Is it true? Yes, sort of.  It ís only found in animal products. But I know quite some people with a B12 deficiency, both vegans as meat eaters.

So how does it work in your body? According to “When humans eat animal foods, the B12 is protein-bound. When the protein-B12 complex reaches the stomach, the stomach secretes acids and enzymes that detach the B12 from the protein. Then, in a process unique to B12, another protein, R-protein (aka cobalophilin, haptocorrin, and transcobalamin I (1)) picks up the B12 and transports it through the stomach and into the small intestine. R-protein is found in many fluids in the human body including saliva and stomach secretions. In addition to B12, R-protein can pick up any corrinoid (2). The stomach cells also produce a protein called intrinsic factor (IF), which travels to the small intestine. When the corrinoid-R-protein complex gets to the small intestine, the corrinoid is liberated from the R-protein by enzymes made by the pancreas (3). Of the liberated corrinoids, only the cobalamins attach to intrinsic factor. Intrinsic factor then carries the cobalamins to the last section of the small intestine, the ileum. The cells lining the ileum contain receptors for the cobalamin-IF complex. The cobalamin-IF complex protects the cobalamin against bacterial and digestive enzyme degradation (4). The IF-receptor also ensures that cobalamins will be given priority for absorption over non-cobalamin corrinoids.”

So if that proces of B12 absorption doesn’t go well in your intestines, you can eat as many B12 sources as you like, your body won’t be able to extract it. That’s why it is important for everybody to get your blood tested on vitamin B12 levels every once in a while.

Symptoms of a deficiency

My friend who had a B12 deficiency suffered from hair loss, cold hands and feet, lack of appetite and sleep disorders. According to OrthoKennis, these are some of the symptoms that could indicate a vitamin B12 deficiency:

  • (chronic) fatigue, feeling of weakness
  • light feeling in the head, dizziness, fainting
  • headache
  • shortness of breath (especially when exercising), rapid breathing
  • muscle weakness during exercise
  • accelerated heartbeat
  • pale skin and lips
  • cold hands and feet
  • yellow discoloration skin and eye white
  • misunderstood long-term fever
  • double vision and blurred vision (weak eye muscles)
  • reduction in vision
  • loss of sense of smell and/or taste
  • decline in hearing among the elderly
  • lack of appetite (weight loss)
  • nausea
  • fast bleeding gums
  • diarrhea or constipation
  • malabsorption
  • menstruation problems
  • reversible hyperpigmentation of the skin (hands, feet, scars) or mucous membranes (mouth, vulva)
  • sleep disorders
  • joint pains
  • hair loss, premature gray hair, friable nails
  • allergies
  • restless legs


If you suspect you might have a deficiency or if you follow a vegan diet: get your blood tested and use supplements. My favorite supplements are the melt tablets, so it’s absorbed easily. They must contain organic B12 and folate and those ingredients must be on the ingredient list in the beginning, not in the end. Good to know: ingredients are placed on packaging in order of presence.

I prefer the biologically active forms over the synthetic ingredients. So look for supplements with methylcobalamine and adenosylcobalamine (also called dibencozide) for the B12 and 500 mcg 5-methyltetrahydrofolaat (5-MTHF) for the folate. In some products, vitamin B12 often occurs as cyanocobalamin and folate as folic acid (pteroylmonoglutamic acid). These are synthetic forms that do not occur naturally and must be converted by the body into the biologically active forms. A problem with pteroylmonoglutamic acid is also that the conversion to 5-MTHF is difficult in a relatively large group of people.

My favorite supplement, from Vitals

Good news for the vegans out there: although B12 is only found in animal products, it is made by bacteria, so it doesn’t need to be obtained from animal products. My favorite B12 supplement?

This one from Vitals. It contains the biologically active forms of B12 ánd folate, and also contains Quatrefolic®, which consists of 5-methyltetrahydrofolate bound to glucosamine salt for stability and superior bioavailability (making it easier for your body to process it). There’s 100 tablets, that’s more than three months of B12 everyday. And it’s really affordable, considering you can use it for three months.

Score your B12 here, at

PS: those who know me very well, know that I would never promote a product I don’t support. This B12 supplement I take myself.

This article was written in collaboration with Vitals.