Vitamin C, Insulin and Hungry Lions

I stumbled on this news item yesterday whilst looking up things Dr Jebb (see yesterday's post) had put out into the world, and it made me wonder just how many people are put off from adopting a more healthy low-carb diet because of the fear of not getting enough vitamin C in their diet.

In fact, these days, the mainstream low carb diets have done a pretty good job of re-branding themselves as "low GI" diets; taking great pains to let people know that vegetables are a significant and important part of the programme.

I eat fruits like raspberries, strawberries and rhubarb because I enjoy them.  And I eat tons of spinach, cabbage and curly kale because I enjoy it too. But never because I think I should.  My skin is great, I can't remember when I last had a cold. My gums never bleed when I brush them....  And I haven't had an apple or an orange in...  I forget when.

There are quite a few animals which only eat meat.  So it would be only too easy to point to them and say - "There you go - Tiger's don't get scurvy!"  ... but it's a bit more complicated than that.

Vitamin C is an essential nutrient.  The use of the word "essential" in this case means that our bodies don't make it on our own.  That's the same reason people bang on about Omega 3 fats - it's an "essential" oil because we can't get it in any way other than taking it from somewhere else, such as cod liver oil or flax seed.  That's why "there's no such thing as an essential carbohydrate."  which is a phrase I never get tired of.

Right - Vitamin C - It goes something like this:

Vitamin C enters your cells in the same way that glucose does.  it's "put there" by insulin, which is a hormone thatregulates a whole lot of things in your body, such as where your blood sugar is stored, and how much your muscle tissue is repaired.  Think of insulin as a gang of builders and you'll remember what it does.  It has an anabolic action, which means it builds, or adds to cell tissue.

Insulin hormones hard at work - they carry glucose and vitamin C in exactly the same way.

 Insulin is happy to deposit vitamin C into cells in just the same way it does with glucose.  You've got cells in your body which really need it, and it's insulin that puts it there.  BUT - if you look at the highly technical illustration above, you'll notice that both the vitamin C and the glucose molecules have the same look to them.  They both enter cells in exactly the same way...

When you take in a sugary carbohydrate, like bread, pasta, chocolate or fruit juice, your blood sugar rises to dangerous levels, and it's down to those insulin workers to get rid of it - quickly!  (otherwise you'll get hot and sweaty and then faint).

Insulin is released into your body in greater and greater numbers to try to get the carb sugars out of your blood.  Your cells are stuffed to bursting point with them - so much so that in many people, they start to refuse it.  Which means your body calls in even MORE insulin workers, who pile in there with crow bars and hammers to force the glucose into storage before it poisons your blood.

Glucose overload - too many carbs mean the vitamin C doesn't get a look in.

As you can imagine.  The poor old vitamin C cells can't compete.  Everywhere it wants to get into is already stuffed full of sugar which is being converted to body fat.  Eventually the insulin will just assume there's no room for it, and flush it out through your bladder.  Bye bye sunny goodness.

If you're lucky enough to be living on a low carb diet, your body makes maximal use of the vitamin C in your daily diet, because it doesn't have to lose it every time it takes in food.  According to Gary Taubes in the book "why we get fat - and what to do about it", if there is no surplus of sugar in the blood, there's "every reason to assume we will get enough vitamin C from meat alone".  As he puts it - it's highly unlikely an Inuit hunter would set out for six months dragging a sledge of oranges behind him.

I've read one or two tall tales that suggest the Eskimo (All Inuit are Eskimo. Not all Eskimo are Inuit) made compotes from berries and oil which kept them going through the winter, but I've read just as many claims which state that you'll probably only find enough berries in the tundra to make a mediocre smoothie.  It's far more credible (at least to me) that they have got their vitamin C from animal products, such as the glands of moose, and certain types of whale blubber.  Click here if you want a cleverer analysis of this point.

So - just out of interest, why don't lions and tiger get scurvy?  Are they necking lemons and oranges while we're not looking?

Well.  No.  It turns out that humans lost the ability to synthesise vitamin C at round about the same time that we started using tools and wondering what the big light in the sky was.  Most other mammals make enough of the stuff in their own bodies and don't need to eat it to be healthy. so - Today's top tip :

If you're ever being chased by a tiger - try to look like an orange.