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Vitamin B12 ... what's the fuss about?

B12, what's the fuss about?

In Otzi's Isotopes I mentioned that 6 of 69 areas of China surveyed in The China Study at no animal products and that these areas had probably been eating this way for a very, very long time. The point wasn't to claim that the diets of any of these areas was optimal, it was part of an explanation of the meaning of omnivore. But these Chinese diets contain no B12 source, so their apparent safety needs an explanation. Without a source of B12, people get sick and die ... it is essential. Contrast this situation with long chain omega-3 oils ... the topic of next week's blog. We can make long chain omega-3s from short chained forms which we have to eat. We are constantly told by all manner of advocates to eat fish to get these long chained forms. Fish, it turns out can't make them, they have to get them by eating phytoplankton, which can, or by eating other fish who have eaten phytoplankton. But that's next week, lets get back to this week.

The short form of the conclusion we'll eventually arrive at is that vegans should take B12 as a supplement ... despite the absence of B12 supplements in the Chinese or other traditional diets that are low or entirely devoid of animal foods. Some foods these days are fortified with B12 and this is fine. A second conclusion will be that everybody over 50 should also be taking B12 supplements, regardless of how much meat they eat.

Rules are like mathematics formulas, much more memorable if you understand what's behind them. The science of B12 is fascinating in its own right, and far stranger than fiction, so you should enjoy it. I won't hyperlink the sources like I usually do but have a reference section at the bottom. All the relevant science comes from just a few key papers, my job is just to explain things in a way that is palatable for people without a solid science background.

Biology's big surprise

The cells of animals are all complex objects with membranes enclosing sub-structures. The most famous of these is the cell nucleus. The cells of bacteria are quite different and don't have a nucleus. But both kinds of cells have DNA ... the stuff of genes. What about plants? Their cells also have a nucleus. Before B12 came along, scientists thought all animals ultimately relied on plants. Animals either ate plants directly or indirectly by eating other animals or both. Then along comes B12. Plants don't make it ... or need it. Animals don't make it but need it. It's so important that animals don't just use it, without it they die. All animals need it: fruit bats, every grazing animal, foliage browsers, seed eaters, and carnivores. Where does it come from? Bacteria make it.

What about spirulina? It's often touted as a B12 source. Is it plant, animal, bacteria or something else? It's a bacteria, more specifically a cyanobacteria. This ancient group of organisms gets its energy from photosynthesis like a plant. Spirulina produces B12, but there are quite a few slight variants of B12 and the variant produced by spirulina is useless in people according to everybody who should know ... except some of the people who make money out of selling it. Eat it if you like the taste, but don't be deluded into thinking you are getting useful B12.

One problem, many solutions

The idea that we need a bacterial product to survive is seriously wierd. Also seriously wierd are the various ways animals have come up with to get their B12. Most animals don't get their B12 by eating other animals. If this surprises you then stop and consider which are there more of, herbivores, omnivores or carnivores? Ruminants like sheep and cattle, have bacteria living inside them. The bacteria colonise the animal's digestive pathway near the top, in the rumen or forestomach. They make B12 which is absorbed as it travels along the remainder of the digestive pathway. Ring tail possums, like that in the picture, use a slightly different system. They also have B12 generating bacteria in their digestive tract, but too far towards the output end to do any good. So the possums do two kinds of feces. One type is fairly dry, doesn't smell much and they eat it and get B12 from it. The other type of feces is rather less palatable! Fecal eating is quite common in the animal kingdom, and has a special name, coprophagia.

We have bacteria in our digestive tract also, but as with the possums, they are too far along for any absorbtion of the B12 to take place. So human feces has plenty of B12. Can we do the possum trick?

Have you got bugs in your guts? ... um, yes!

Let's go back a step. How do we know we have B12 in our feces? In 2010, non-scientists who watch a lot of TV think that scientists just put the feces in a machine which will tell them within seconds exactly how much B12 is in the sample. The real world isn't so simple and back in the 1950s, when scientists were working out the details of this area, getting answers to questions like this was even tougher.

But here's a foolproof method. I could tell you not to try this at home, but I doubt you'll be tempted. Find some people with a serious B12 deficiency. Take their feces, dry it out so its not quite so unpalatable and feed it back to them. If they get better, then the feces contained B12. If not then at least you'll know we aren't possums! Pioneering medical scientist Sheila Callender did exactly this with some B12 deficient patients back in the 1950s. The cure worked.

Early battery hen farmers confirmed the theory. Their hens in cages on a diet of straight grains got sick. Add B12 to the mix and they get better. Most of the world's production of B12 is fed to animals. Let hens peck around in the dirt and they can survive on a diet of grains without difficulty. The dirt provides the B12. One of the core elements in the B12 molecule is a single cobalt atom. If your soil is cobalt deficient, then the resident bacteria can't make B12. In this case, your hens will die. Cattle farmers have known about cobalt deficiency problems for over a hundred years ... long before anybody knew about B12. They provided cobalt directly and the rumen bacteria did the rest.

All the science I've been describing was done a very long time ago with B12 being successfully isolated from liver extracts in 1948. Why the liver? If you eat more B12 than you need, the excess ends up in the liver. People on meat based diets get more B12 than they need so their livers gradually become full of the stuff and liver extracts were used to treat B12 deficiency symptoms a long time before anybody knew what B12 was. The eventual discovery of B12 explained things that people had been doing for a very long time without understanding why they worked.

Similarly, the presence of B12 in human feces explained something which had puzzled scientists for some time. A group of vegans in Iran had no apparent source of B12 but no symptoms of B12 deficiency. How could this be true? It was finally realised that the group used their feces as manure. Residual fecal contamination of their veggies did the rest.

The Iranian vegan story illustrates how astonishingly efficiently we recycle B12.

Practical consequences and FAQ

The China Study doesn't explain how the areas without a B12 source stay healthy. The mechanism is probably via the use of human manure. There is a long history of using human manure in many cultures across the planet. For Australian vegans living on shop-bought food, fecal contamination would be minimal or zero and never desirable. Any contamination is almost certainly from factory farmed animal feces. In addition to B12, such contamination could contain a range of unhealthy viral or bacterial components. This is the source of most food poisoning.

B12 exists in nature in many slightly different forms. The form used in most supplements was first synthesised chemically in the 1970s after about 11 years of work by 100 scientists. These days, commercial B12 is produced by bacterial fermentation processes which are highly efficient and far preferable to any half-baked attempt to use your own feces as a source.

So, with that in mind here's my take on reasonable answers to frequently asked questions.

What's B12 for?

B12 is involved in some basic functions in every cell in your body. Deficiency progresses through a few stages and usually involves nervous tissue problems first and can progress through to fullblown degeneration of the spinal chord. Mild deficiency shows no obvious symptoms but causes a rise in homocysteine levels which can result in heart disease, stroke, and other vascular disease. This is part of why developing countries can get heart disease without high intakes of saturated fats.

How much do you need?

Our bodies are extremely efficient at conserving and recycling B12. A person raised on meat who becomes a vegan could take 20 years to develope symptoms. But a baby with a vegan mother and no source of B12 could develope symptoms within months when the store they were born with started to run low. In some cases, damage can be permanent.

People with B12 deficiency symptoms usually start to recover with very tiny doses ... as little as one twentieth of the recommended daily dose of 2 micrograms (ug). So the recommended daily dose has a huge safety margin built in. There is no evidence that more is better so a glass of fortified SoGood soy milk with 1 (ug) would probably be adequate despite being half the recommended daily dose. There is also no evidence that large doses are either harmful or helpful. Cheap B12 supplements with 2 (ug) are fine. Sometime multivitamin tablets are cheaper than B12-only tablets. But beware mega doses of B12 ... or anything else. No evidence of harm isn't the same as evidence of safety.

How do B12 tablets compare with natural B12?

Synthesized B12 is better than the B12 in animal products for many reasons. Let me count the ways:

1. Cost. I'm not talking necessarily about the shop price, but am considering all costs. Dairy milk has about the same amount of B12 in it as fortified soymilk (e.g., Sanitarium), but the environmental and animal welfare costs of soymilk are significantly lower. For example, the dairy industry has been the biggest user of water from the Murray Darling Basin for 20 years and its expansion during the late 1990s was a major factor in the crippling of the basin.
2. Bioavailability. For many people, synthetic B12 is absorbed more readily since it isn't bound to an animal protein. This is why the US Institutes of Medicine recommends that all people over 50 take synthetic B12 (regardless of animal product consumption).
3. Global Warming. Cattle produce prodigious amounts of methane with dairy cattle producing the most because of the richness of the feed.
4. Nitrogen pollution. Dairy cattle are typically raised on highly fertilised feed. Nitrogenous fertiliser run off and leaching into surface and underground water courses is a major global dairy industry problem.

But it's natural

Regardless of how lucky we were with our choice of parents, we all eventually realise that our parents aren't perfect. They have good points and bad points. So it is with mother nature. By which I mean evolution, the force that drives many, but not all things. Sometimes the solutions evolution comes up with to problems are ugly, crude, inefficent, cruel or all of the above. Human have evolved a brain that has produced a far better solution to our B12 sourcing problems than mother nature. Some people choose the old ways, vegans embrace the new, not because it's new, but because it's better.

Can we produce enough B12 to replace animal foods as a source

We already do! 1 microgram per day for 6.7 billion people is about 2.4 tonnes per annum and the current global B12 production is about 10 tonnes per annum.

Sources

One of the key scientists studying B12 in the second half of the twentieth century was Victor Herbert. He wrote a great summary on B12 science here. A great review from a more theoretical viewpoint is here.