Are vegans B12 deficient?

Peter Julian Owen, a consultant orthopaedic surgeon at Addenbrooke’s hospital in Cambridge. He is also the co-founder and chair of CluB-12, which attempts to understand the importance of Vitamin B12…

Peter - I founded CluB12 very shortly after a tragedy in our family where my daughter took her life. She'd been vegan for three years and I must confess my memory of vitamin B12 from medical school was a bit distant, and we knew she should be taking it on a vegan diet and encouraged her to do so, but it transpired that she hadn't been taking it and it was more sporadic and she'd become a bit anxious. So, we said, take your B12, unbeknownst to us that she should have had intramuscular. She had oral and three weeks later she became psychotic and took her life. It just turned our world upside down. It's quite clear to me there's a lot of ignorance within medicine about the significance of this very important molecule.

Chris - It's a horrible thing to have had happen to you. How did you link that to the B12, though?

Peter - Back in med school I was taught about megaloblastic madness and that was the term for vitamin B12 deficiency. And sure enough, when you go back into it, anxiety, depression and psychosis are all part of the B12 deficiency spectrum. Presentation wise, only 15% of people present with an anaemia or megaloblastosis, which is the megaloblastic bit of that megaloblastic anaemia. So 85% of people will present with a neuropsychiatric problem. That's the first part of this ignorance because we don't appreciate that we look for for an anaemia with B12 deficiency. Georgina had said, I feel a little anxious, I think I should have been taking my B12, and we've since looked at her diaries - we wouldn't have done before she took her life - and found some writings, 'I'm going to stop being vegan. I'm going to eat some eggs, have some fish, change my diet round.' Tragically, too late to turn it around. With a dietary change, when you're that deficient, you need intramuscular B12. The reason being that three milligrams of our body is vitamin B12 when we've got enough, when we are replete. Very small amounts. But if we drop down to a milligram, there are severe consequences of that. To get your body back up, with two milligrams, and only absorbing two micrograms of a tablet going past the absorption part of your bowel called the ileum, you are not going to take that B12 level in the cells back up very quickly. It'll take you 200 days, perhaps. But you can give an injection and you can get 100 micrograms of the milligram into the cells. The other 900 micrograms drifts out in the urine. But you can see how having an injection every other day, after 10 days, you've put another milligram back into your cells and that's how you replenish someone and get them through these dreadful situations.

Chris - What does B12 do in the body?

Peter - The textbook would tell you the molecule attaches to an enzyme, so vitamin B12 is a co-enzyme in the main part of the cell called the cytosol. It works on an enzyme called methionine synthase, and that's part of a cycle, like you might know about the Krebs cycle. This is called the one carbon cycle and and that creates little methyl groups, carbon with three hydrogens, which is a building block for nature; for DNA, for RNA and many processes in the body. If you don't have a functional one carbon system, you can't methylate and that has dramatic consequences. There's another enzyme in the mitochondria which are for energy production within the cell called Methylmalonyl-CoA mutase, and that also has vitamin B12 as a co-enzyme. That might be responsible for the energy people seem to lack in B12 deficiency.

Chris - Where do we get most of it from?

Peter - We get ours because we eat animal products and the animals that we eat, or the products we eat, have managed to filter out the B12 for us. So if you put that the opposite way round, if you think of a vegan diet, that is an exclusion diet, so you won't get any B12 of any significance in a vegan diet.

Chris - Does that mean then that anyone eating a vegan diet is probably B12 deficient or is at least at very high risk of becoming B12 deficient?

Peter - People feel it might take two or three years to become significantly B12 deficient, but unless you supplement or find another source of B12, you will become B12 deficient.

Chris - Are the supplements all right? If you just eat some supplements and you're vegan, will you get enough B12?

Peter - The problem with the supplement is that the human body is used to having a drip feed of B12 in every meal. So if you take a large dose of vitamin B12, you will only capture two micrograms of it through the very specific uptake mechanism. But you can absorb a little just passively through your whole bowel, about 1%. The problem with that is the rest of that B12 goes into your colon, and there are some studies that show it changes your biome. There are even studies to show it turns the B12 into an non-vitamin called pseudo B12. And pseudo B12 has been found in some diseases in the body. It's a whole science we've yet to understand. There's another issue with the supplements that the active form that defines it as B12 is attached to the bottom of that disc. But at the top, that's what defines what we would find in the shop. We'd find a methyl B12 or a cyano B12 or a hydroxy B12, and the cyano is the most stable and doesn't react to light, but the methyl slowly degrades. Some of our members within our group cluB12 have been testing supplements from the shops. And yes, there are degradation products. They're not what they say they are on the tin. So a good varied diet is more likely to give you the nutrients you think you're getting.