All right then - a deep dive on Vitamin C.
Vitamin C, also known as L-ascorbic acid, is a water-soluble vitamin that is naturally present in some foods, added to others, and of course available as a dietary supplement. Quite often in fizzy tablets, loaded with sugar. Humans, unlike most animals, are unable to synthesise vitamin C endogenously, so it is an essential dietary component.
I should pause for a second an examine the word "essential" because I see it continuously popping up in articles in the general media, boosting some superfood, or whatever - such and such is an "essential part of a balanced diet".
In the strict medical sense, essential means simply that we cannot make it ourselves. It really calls back to the essential meaning of the word, the inherent part of a thing - the essence. So, for example; "Essential oils for meditation" does not mean that these oils are required for the act of meditation, it just refers to the important bit of the oil, the thing that's necessary to have any meaning, rather than just oily lubricant.
This is important to understand, because there is often clever marketing involved, suggesting that this thing you cannot make, is also necessary to be healthy. That isn't always the case. Anyway, I digress.
Back to vitamin C.
Famously, vitamin C as a supplement goes way back to 1747, even before anyone ever had a single argument about saturated fat; A ship's surgeon (A Scot called James Lind, as it happens) decided to figure out what could be given to the sailors to stop scurvy. A set of experiments led to lime juice being given to all the ships company in a rare example of evidence-based nutritional guideline changes.
So goes the story - and so it was (at least far as I can determine from my perspective nearly 400 years later). Brits have ever since been known as "Limeys" and inside this sceptred isle, we have a picture of our expansionist navy cleverly using the secret power of citrus fruit to expand our sphere of influence into the largest empire the world has even known.
That sense has persisted, and I recently saw an interview with a qualified and experienced nutritionist who was reviewing the carnivore diet, and confidently dismissing it, because - well "who want's scurvy".
It's an understandable connection - scurvy is simply a deficiency of vitamin C (look up almost any obvious source and that's what it will say) - symptoms can be reversed almost immediately with citrus fruit, so a diet with no citrus fruit for periods of several months put you at risk of scurvy - right?
Pretty clear, except for the annoying fact that if it was that simple, nearly all human populations should be dead. Long dead. So there has to be more to the story.
The most obvious thing to say is that way back in the eighteenth century, returning to HMS Salisbury; it's worth noting that is was only the ordinary seamen who were dying from scurvy - not the officers. How could that be? Well, the stores, the cooking, the dining; were all split by rank. Commissioned officers ate very well, whereas the hands mainly subsisted on ship's biscuit and beer. Meat was eaten, but rarely and all dried. No veg.
So, let's leave naval warfare, and consider what Scurvy is. Again, most sources simply call it a deficiency of vitamin C, so that's a bit circular and unhelpful. We all have images of bleeding gums, but what is actually going wrong, what is the pathology?
Well, it's remarkably similar to the haemoragic fever that characterises Ebola infection. As a complex organism, we are a collection of systems, separated by membranes. Most obviously, the digestive system is a tube that goes all the way through us, and the stuff inside that system are separated from the rest of the body, outside the system. The Vascular system similarly. At the membranes of all these systems, complex processes allow the things that should cross over to pass through, and to stop everything else. In Scurvy, and Ebola, these barriers break down, and stuff begins to leak all around the body - thus blood leaking out of the gums.
So then, its worth looking deeper - a vitamin deficiency and a contagious virus sound very different, but there are some learned connections - Dr Thomas Levy wrote after studying and treating outbreaks; "the virus so rapidly and totally metabolises and consumes all available vitamin C in the bodies of victims that an advanced stage of scurvy is produced after only a few days."
So, the Effect of the ebola virus is to cause scurvy.. by consuming, or shutting down access to vitamin C.
Dr Robert Cathcart, who has more experience treating potentially deadly infections with high dose vitamin C than any other doctor maybe anywhere, says “the Ebola virus kills by way of free radicals which can be neutralised by massive doses of sodium ascorbate intravenously".
In other words, ebola can be combatted with massive vitamin C dosage, and that free radicals are the underlying cause. Now we're getting somewhere.
By the action of virus, or acute shortage of vitamin C, free radicals (reactive oxygen species, or ROS) build up to a point where they can smash down the barriers between our systems, and stuff starts to leak into places they shouldn't be, and we're in big trouble.
And we're back to a critical balance we all have to manage - oxidative stress - that fundamental Faustian (or Promethean, if you prefer your tragedies to be Greek) bargain that our ancient ancestors made with the explosive power of oxygen. You can get all the power you need to become complex animals, but that oxygen is always going to be looking to blow up - not in your face, but in each and every cell, all the time, and you'll need an army of anti-oxidants to keep dealing with it. If you run out, or get too old to keep producing enough; you die.
After digging about as deep as my sanity allows, that's where I land - vitamin C - ascorbic acid - it isn't so much that you must eat citrus fruit or you will have scurvy, it's that the more your metabolism is prone to oxidative stress, the more anti-oxidants (which include, but are not limited to, vitamin c) you will need, and citrus fruit is a hugely effective source.
"But,", I hear you all say in unison, "if vitamin c, a pesky little acid, is so effective in the fight against our oldest enemy, ROS, then why did we lose the ability to make it for ourselves - most other animals can, why not us?"
And - of course - that opens up more questions than it answers.
The answer to when? is about 40 million years ago, with a mutation to the GULO gene, which is responsible for the last stage in the production of the enzyme that synthesises vitamin C. This affected all (most?) of the great apes that we evolved from.
Why? - that's more difficult.
I can't say for a certainty, but there are articles which lay out the evolutionary advantage of this mutation. It's pretty complicated, but the simple version is that we lost the ability to make vitamin c and gained a more efficient way of allowing glucose to enter the cells (and specifically red blood cells); creating energy in a way that produces less ROS, thus requiring less antioxidants.
Specifically, this led to changes in the Glut-1 transport. You may have heard of it, it's one of the important entranceways to red blood cells for glucose, and (as far as I understand it) means less vitamin c is required, but also makes red blood cells more energetic in the way that they can store and deliver anti-oxidants to where they are needed around the body.
Red blood cells have no mitochondria and can only create energy directly from glucose - they cannot use oxygen, because their purpose is to transport oxygen.
Bottom line, there seems to be a benefit overall in the "pros and cons" involved in the mutation that stopped us from making VC.
A final thing to say is that in the gut - vitamin c and glucose compete for the same route through the gut lining (that whole thing about the transport in the red blood cells points to how similar in structure vitamin c is to glucose) so if your food is high in glucose, this will limit your ability to absorb vitamin c. This actually puts non-starchy veg at the top of the list for best vitamin c, but also; the less glucose in what you eat - the less vitamin c there needs to be in what you eat, in order to absorb enough.
To come full circle, there is a small amount of vitamin c in meat (and quite a lot in liver and pate). I had thought there may be a lot in black (blood) pudding given that I've just laid out how blood cells can be a "storage pool" for vitamin c - but of course that only applies for that gene mutation, which doesn't apply to the animals that we tend to make black pudding out of.
But - either way - this is why people on carnivore diets aren't all keeling over with scurvy after a few months. We are evolved to need less, you absorb more in a low carb diet, and there is some in meat.
Also - a good diet, which includes in my opinion, (but is not limited to) carnivore, will reduce oxidative stress by definition. A diet high in carbs, industrial seed oils and additives from ultra-processed food-like stuff; will lead to mitochondria operating less than optimally, and that means more oxidative stress; which means a greater need of anti-oxidants like vitamin C.
Final point (honestly)
The job of Vitamin C isn't just to mop up ROS, it's a much more involved enterprise involving breaking down, repairing and building up those membranes and structures. Collagen is involved, and a whole host of other particles and processes. I've really focussed on ROS to leave a story that is somewhat easy to follow, but of course there is more.
There is a strong line of thought that as we (humans now) evolved more and more to process meat (the evidence being the increase in brain size, and shortening of the intestine), and as such, evolutionarily - we turned to a lipoprotein to do the job of vitamin C. Lp(a) - pronounced "El-pee, little a". That's a whole post to itself though.
