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[Siquo]

Which is pretty much what most dieticians will tell you - "Everything in moderation, make sure it's varied, eat your fruit and vegetables". 

True, very true, mine tells me that on a daily basis , with a few exceptions:
It's easy to run out of vitamin D for us "inside people in the dark northern hemisphere", especially children are advised to add some in the winter.
Smoking and alcohol break down vitamin C, taking a bit extra when you're "under the weather" can help.
And there's a few other, but I can't be bothered to bother my dietician. Note that yes, you can "overdose" on vitamins, and too much of them can damage your body.

If they exist at all, of course.


Probiotic studies: check the reference list: http://en.wikipedia.org/wiki/Probiotic

[Leafsnail]

Oh, yeah, D can be a problem.  Although that's generally only if you spend literally all day indoors  - we developed white skin up here for a reason .

I guess I'll go read the probiotics literature (although, for the record, I drink it coz it tastes nice in the morning).

[Bauglir]

Oh, yeah, I know they don't handle a lot of vitamin stuff (they do make K, but not enough), but part of that is because if they make enough of it, it's not a vitamin. That said, most of what they do in humans is just convert random stuff that couldn't be absorbed earlier up into things that can be and mooch off bile for nitrogen, IIRC. Much more important in ruminants, but that's not really relevant. I think, in retrospect, I was exaggerating when I said "tons of shit".

[ECrownofFire]

Vitamin K is actually necessary for clotting. Which means too much spinach or broccoli can actually give you a heart attack.

By the way, check this out, it has some nice information. I'd check the source list a bit though.

[Bauglir]

Vitamin K is actually necessary for clotting. Which means too much spinach or broccoli can actually give you a heart attack.

By the way, check this out, it has some nice information. I'd check the source list a bit though.

Isn't K water-soluble? I could be wrong, I'm kinda going off memory and I haven't constructed a balanced diet since Freshman year and realizing that broccoli and spinach together supply some of everything (although I did a better job of it than that then, that's what it boiled down to). Still, the water-soluble ones tend to be next to impossible to overdose on unless you're also dehydrated, since you can get them out through the urine fairly easily.

[ECrownofFire]

Vitamin K is actually necessary for clotting. Which means too much spinach or broccoli can actually give you a heart attack.

By the way, check this out, it has some nice information. I'd check the source list a bit though.

Isn't K water-soluble? I could be wrong, I'm kinda going off memory and I haven't constructed a balanced diet since Freshman year and realizing that broccoli and spinach together supply some of everything (although I did a better job of it than that then, that's what it boiled down to). Still, the water-soluble ones tend to be next to impossible to overdose on unless you're also dehydrated, since you can get them out through the urine fairly easily.

Wikipedia says fat soluble, so no.

[Bauglir]

Huh. Thanks for the reminder, then! I'll keep an eye on that in the future.

[Micro102]

I never understood how you get vitamin D from light. The closest answer I can get is that the light creates a chemical reaction in your skin that produces vitamin D. But we are already being bombarded with tons of electromagnetic waves. So why sunlight?

[Bauglir]

I never understood how you get vitamin D from light. The closest answer I can get is that the light creates a chemical reaction in your skin that produces vitamin D. But we are already being bombarded with tons of electromagnetic waves. So why sunlight?

I don't know exactly, but I'd wager that it requires a specific wavelength of light to excite the protein appropriately. Too high might just denature the sucker, too low won't give it enough energy to put the reaction through.

[ECrownofFire]

I never understood how you get vitamin D from light. The closest answer I can get is that the light creates a chemical reaction in your skin that produces vitamin D. But we are already being bombarded with tons of electromagnetic waves. So why sunlight?

I don't know exactly, but I'd wager that it requires a specific wavelength of light to excite the protein appropriately. Too high might just denature the sucker, too low won't give it enough energy to put the reaction through.

Wikipedia exists for a reason you know.

Vitamin D3 is made in the skin when 7-dehydrocholesterol reacts with UVB ultraviolet light at wavelengths between 270–300 nm, with peak synthesis occurring between 295-297 nm.^[12] These wavelengths are present in sunlight when the UV index is greater than 3.

[The Doctor]

Why Sunlight? Same reason plants use it for photosynthesis. It's there, that's why.

[Urist Imiknorris]

It's there and it's exploitable.

[Bauglir]

I never understood how you get vitamin D from light. The closest answer I can get is that the light creates a chemical reaction in your skin that produces vitamin D. But we are already being bombarded with tons of electromagnetic waves. So why sunlight?

I don't know exactly, but I'd wager that it requires a specific wavelength of light to excite the protein appropriately. Too high might just denature the sucker, too low won't give it enough energy to put the reaction through.

Wikipedia exists for a reason you know.

Vitamin D3 is made in the skin when 7-dehydrocholesterol reacts with UVB ultraviolet light at wavelengths between 270–300 nm, with peak synthesis occurring between 295-297 nm.^[12] These wavelengths are present in sunlight when the UV index is greater than 3.

Eh, I drown in enough biochem during the day (little of which is nutrition-related, unfortunately). On the plus side, I was right, which isn't too bad for being something like the worst student in the world with my GPA (I'm a lucky bastard on exams, mostly).

[Starver]

I'm fairly sure almost nobody gets enough Vitamin Wonka...


Anyway, onto "why Vitiman D from sunlight"...  I'm sure there are good studies about the reasoning behind it, which I won't chase up, but I'd go for:

1) At one point in our evolutionary history (way, way back) a side-effect of a certain biological process in some organism was a precursor molecule of VitD.  It probably had no use at that time, but was either non-harmful or not significantly so.  Just like a lot of other molecules have occurred and been similarly (near-)benign to a system...  including not being resource-wasteful.
2) At some point, perhaps aided by another happenstance reaction with an enzyme, this molecule happened to react with sunlight and create VitD.  Which at that point was also similarly benign and not significantly resource-wasteful.
3) But it did something.  And whatever something that did started to convey an advantage to the descendants of that original organism.
4) Eventually, it became Important.

It might easily have been something else that became Important.  Aand, indeed, several other "something elses" became the Important things that we know as the other Vitamins, and others we probably don't even know about...  (Or don't realise.)  And not just single items, interactions between multiple molecules is essentially what life is, and we only know a fraction of the "whys and wherefores" (or at least the "wherefores", as there is no "why" in the strictest sense).

edited to correct failure in hand-coded closing format tag

[Siquo]

Ah, but the reverse is more important, nowadays. People often think evolution favours complexity and more features, while the opposite is usually the case. Most animals can produce their own vitamin C, but we and several other fruit-eaters can't. Probably because we no longer needed to, because we ate fruit. Degeneration in genes is much more pronounced and a lot quicker than new abilities. See for example troglobionts, or cave species. Most, if not all of them lost all pigment and vision (genetic convergence), and haven't been separated from their surface-dwelling cousins for that long, as most limestone caves aren't very old. Because of vitamin D supplements, we will slowly lose the ability to synthesize it ourselves.

So, by keeping the weak, sick, and degenerate artifically alive and reproducing, we are quickly degenerating our species, where we can no longer survive without technology. The other option, however, is even worse.