Friday, 21 September 2012

The Juice on Oranges

How much Vitamin C, (ascorbic acid) do you need. Why do you need it?
RDA between 10 and 90mg for adult humans. To prevent scurvy and possibly other undesirable things.

10mg seems to be the bare minimum, and 90 to 200mg seems to be a good target. 500-2000mg (2 grams) seems to be overly excessive, (like double double superlatives or a tautology.)

"but 10-200 seems a rather broad range?"

Yes. This is because we are all different, (which is why Doctors practise medicine rather than 'doing medicine' - or so I like to think of it; It is not that they hope to be good and get it right some time in the future.)

So what is the problem? Well the human body does not store vitamin C. It is lost at about [a few] mg/day, implying that it has a half-life of days, (lets say 83). Massive excess is filtered from the blood stream by the kidneys, (rather impressive filters they are!) and ejected through urination, (though I still feel that humans missed out not having a cloaca like some birds.)

So what is the density of Vitamin C in freshly squeezed orange juice?

100 grams of OJ has about 50mg of Vitamin C. Thanks to the metric system 100g = 100ml (well for water at 20 degrees Celsius.)

[If you have a small Nutella (tm) glass, (and who does not?) then they are helpfully marked with four lines: The peak of the top one is about 130ml, the next one is about 85ml, then 55ml, then 30ml. (Full-to-the brim is about 240ml with 200ml being a "won't spill too easily, but feels full" serving.) So you might think that you need half a glass of OJ a day? Read on to see why NOT.]

Vitamin C seems to be a bit of a pain; What does it have on its resumé? Well it is water-soluble. This means that the villainsed "fats" (lipids) are not required to get it into your body. The best thing is that Vitamin C turns up everywhere! Are you planning on having something to eat today?

A serving of just 70g of raw cabbage, (yes you can, think coleslaw) can have over 40% of your RDA of Vitamin C, (and over 60% of your RDA of Vitamin K {what ever that might be}).
That glass of orange juice just dropped to the quarter-of-a-glass mark, (sorry Tropicana).

At this point I'd like to point out that with unlimited funds I would have my slaves bring me a different 1Liter Tropicana each day, and not tell them which one I wanted, (mostly because I don't know until after I start drinking, though Grape, (either colour) or something with mango and passion fruit rank highly.) The one that guessed correctly gets to eat lunch that day, (see I'm almost-not drunk with power in my imaginary world.)

So Vitamin C does not just live in fruits. It can even be found, (in tiny amounts) in the herb basil. Do you eat onions? 160g of onion has about 20% of your RDA. Even if you are not chugging down five cups of raw onion each day, these things all add up nicely, (hence the term, "a balanced diet".)

180g of Spinach not only has about 30% of your RDA of Vitamin C it has over 1000% of your Vitamin K, (yes that one again) and over 300% of your Vitamin A, (which is needed by your eyes, and other things.)

So if you take care to eat food, (rather than junk) you should only need a top-up at the weekends of orange juice, (when you are indulging in that "English Breakfast" that undoes all the good work that you did the rest of the week.)

So? Feeling evolutionary superior: Goats synthesise their own vitamin C, (humans can't.)

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