Sorry this video took a little longer than usual guys, this topic turned out to be far
more expansive than I was expecting and I actually made a slightly concerning discovery
during my reading that has changed my own B12 regimen and my recommendations for supplementation.
This video will be unavoidably quite technical at times, but make sure you stick with me
until the end to find out what I discovered and my new recommendations.
The single-celled organisms bacteria populated the Earth millions of years before humans
did.
To allow them to extract energy from food they evolved a large molecule called cobalamin.
Since bacteria were so abundant as more complex organisms like ourselves emerged, we became
dependent on them in many ways as we co-evolved.
One such way is our absolute requirement for this molecule cobalamin for our own normal
function - or as it's known in this context, vitamin B12.
Other animals require B12 as well, and must also get it from bacteria and similar organisms.
No multicellular organism has the ability to synthesize it themselves, which is why
most have evolved elaborate ways of absorbing very small amounts of it very effectively,
and even the ability to store it - a trait normally restricted to the fat-soluble vitamins
A, D, E and K.
This storage ability is why B12 ends up in animal products, especially the liver and
kidneys - not because the animals synthesize it themselves.
B12 has two main functions in the body - it is used in an early step in the synthesis
of DNA and in the formation of myelin - the electrical insulator of our neurons.
In it's DNA synthesis role, B12 is used to recycle another B-vitamin, folate, which is
required for DNA synthesis.
If there is no B12 coming in, the whole process grinds to a halt and no DNA can be made.
The biggest ongoing requirement for DNA synthesis in our body is blood cells, especially red
blood cells - billions are made each day.
So when B12 is deficient, classically a patient will end up with anaemia with a specific clinical
pattern that is recognisable, and importantly, diagnosable and reversible.
However, those eating a whole foods, plant-based diet may take in so much folate from fruit
and veg that they can actually circumvent this requirement for B12 because they have
enough folate coming in all the time that they don't need to regenerate it with B12
as much.
So good news for those eating healthier diets?
Unfortunately not - high intake of folate "masks" this PARTICULAR consequence of B12
deficiency, so a patient may never develop symptoms of anaemia - but instead allow their
deficiency to progress untreated and to result in even worse consequences.
High intake of folate may somewhat negate the need for it to be recycled by B12, but
look what else is happening in the process - homocysteine is converted to methionine.
Homocysteine is an intermediate in the metabolism of the amino acids methionine and cysteine.
However, it interacts with proteins differently than these amino acids.
If it accumulates to high enough levels it can form abnormal bonds with proteins and
impair their function, most importantly in the lining of our blood vessels.
The altered function of this lining renders the blood vessel more atherogenic, and this
is a proposed mechanism by which raised homocysteine levels increase the risk of cardiovascular
disease.
Moreover, the myelination process is completely seperate from folate anyway, so overt B12
deficiency will eventually lead to an inability to electrically insulate our neurons, and
they begin to die.
This process begins in the spinal cord, and as B12 deficiency progresses untreated, the
condition subacute combined degeneration of the spinal cord develops - eventually resulting
in paralysis.
High folate intake can mask the haematological consequences of low B12 intake, making it
theoretically possible for those eating healthy diets rich in folate but without paying attention
to B12 to encounter these severe neurological symptoms as their FIRST warning sign of inadequate
B12 intake.
Methionine itself, an essential amino acid, is also low on a whole foods, plant-based diet.
This is actually good news though, as low methionine intake may extend lifespan and
help fight cancer.
However, their low intake makes it all the more important that those eating healthy are
able to recycle their methionine effectively, thus again neccessitating good B12 status.
A large portion of our methionine requirement is simply to synthesize the non-essential
amino acid cysteine, so having a good cysteine intake from foods like nuts, seeds, legumes
and oats spares some of our requirement for methionine.
This is why the recommended methionine intakes are usually given along with cysteine.
Suffice to say, regardless of diet, methionine deficiency is extremely rare.
So avoiding foods rich in this amino acid is a viable strategy as long as adequate B12
is consumed.
Getting back to B12 itself, at this stage it's pretty clear we need to have a good supply
of this key vitamin.
But how do we know if we're getting enough?
Serum B12 concentration is a common blood test available in most hospital labs and a
normal result is reassuring.
However, it is possible to have functional B12 deficiency with a normal serum B12 level.
HoloTC is a marker of actual functional B12 levels in the serum, but not everyone will
have access to this test and because of it's relative novelty no exact reference ranges
have been determined.
Ideally, we would use all B12 biomarkers to build up an accurate picture of B12 status,
but in reality we must work with what we have available.
The weakness of the serum B12 test becomes even more apparent if eating certain foods
such as blue-green algae that contain inactive analogs of B12 that can interfere with the
test.
So you're probably convinced at this stage you need a good source of B12.
As I mentioned earlier, B12 is present in animal products, expecially liver and kidney.
However to get B12 this way, you also have to accept all the baggage that comes with
these products - all the saturated fat, cholesterol, animal protein, hormones and so on.
And even after all that, a large proportion of meat-eaters of all ages still end up B12
deficient!
Supplement users have the best levels overall - supplementation is the best way to ensure
adequate B12 intake, regardless of diet, and this is how I recommend you get your B12.
But how much should you take?
If the adequate intake is around 4 μg, why do so many supplements dose B12 in the 100s
or 1000s of μg?
B12 supplements are designed to be taken daily or even less frequently.
And the thinking goes that whilst 4 μg would be enough if taken in multiple doses spread
out throughout the day, because of the absorption dynamics it is possible that not enough of
this would be absorbed if taken in one sitting.
The vitamin's specific absorption mechanism is saturated at around 1.5-2 μg in one meal,
and because this mechanism requires multiple complicated steps and conditions to be present
it can fail, especially as we age and due to the use of certain medications.
The mega dose is used to take advantage of non-specific absorption of B12, by which 1-2%
of the dose makes it into our blood stream.
This is why B12 supplements often contain these high doses.
But remember, this 4 μg number is already taking into account a wide range of conditions,
intake patterns and variations in absorption in the population - it is not the amount used
by the body per day, but the amount required to be taken in to maintain normals status
in most people, taking into account incomplete absorption and with a good margin of error.
Indeed, B12 supplementation does increase serum concentration in those with a low level
at baseline, but larger supplemental doses appear to provide no additional increase in
serum concentration over more conservative doses.
The reason I am getting very specific here is because the current approach of megadosing
the vitamin to ensure you're getting enough and not worrying about adverse effects from
high doses may not be as safe as we once thought.
Higher B12 intake has been associated with higher rates of oesophageal cancer, though
it isn't clear whether or not this is just due to B12 being a marker for animal product
intake which itself is a known risk for oesophageal cancer.
However, there is emerging epidemiological evidence that long-term SUPPLEMENTAL B12 is
associated with an increased risk of lung cancer in men as the dose increases.
This evidence is only emerging and there is a huge amount of data to say that high-dose
B12 is safe, but given that it is likely most people will get all they need from more conservative
dosing, I have changed my own regimen and will now opt for the lowest-dosed B12 supplement
I can find.
I think this is a safer strategy for most people along with getting your status checked
every so often.
Perhaps it's time we began to move towards saving megadosing for those with confirmed
absorption issues, rather than as a blanket supplementation strategy.
Specifically, a low-dose cyanocobalamin supplement is probably best for most people since it
is the best-studied and most shelf-stable and you know exactly what dose you're getting.
I think getting all your B12 from fortified foods is possible, and I'm actually slightly
more in favour of this strategy after reading about the risks associated with high-dose
supplementation, but it takes a lot more planning and is less fool-proof, so my recommendation
is to stick with a conservatively-dosed supplement for convenience.
Hold on a minute, though.
If whole plant foods are the best thing to eat for our health, why do they not naturally
contain B12?
Why should there be any need to supplement anything?
How did our ancient ancestors get their B12, they weren't taking any supplements and they
certainly weren't getting 100s of micrograms of cyanocobalamin every day!
Well, our World is different to that of our ancient ancestors in many ways, not least
of which is the widespread practice of hygeine.
As I mentioned, bacteria and similar organisms are the original source of B12, but in our
modern hygeinic World we no longer have bacteria-containing faecal matter contaminating our water supply
and we no longer have bits of soil stuck to our food - which overall is certainly a good
thing!
I'll definitely accept B12-deficient water if it is also cholera-deficient water!
The fact that bacteria were so abundant before the concept of hygeine meant that B12 was
also abundant and was a part of every meal, so we could rely on the B12-specific absorption
mechanism I discussed, absorbing 1.5-2 μg every time we ate or drank water.
Remember, even our food animals have to be supplemented cobalamin today.
Because our modern World is such a departure from the World we did most of our evolving
in in so many ways we have to make many changes to the way we live.
Thankfully supplementation is one of the simpler changes.
So to summarise all of this, because we co-evolved with bacteria for 100% of our evolution we
depend on them in many ways, such as our requirement for the vitamin B12 that they make.
Maintaining a good B12 status may be even more important in those eating healthy.
Commonly-available testing is a good indicator of status but not absolutely 100% reliable.
In my opinion, for most people the best way to ensure a good intake of B12 regardless
of diet is a conservatively-dosed cyanocobalamin supplement to make up for this B12-deficient
World we live in.
Apologies for the detailed parts of this video, but I hope it's given you a better understanding
of vitamin B12!
Let me know in the comments what your own B12 regimen looks like and if this video has
made you think about changing it!
If there was something that wasn't clear from the video or you have any questions or comments
feel free to let me know and I'll get back to you.
Be sure to share this video with anyone you know who may be concerned about B12 and hit
that like button if you found this overview informative.
That's it for now though guys, talk to ye soon.
Sláinte!