Posted by Larry Hoover on November 4, 2004, at 12:18:00
In reply to Re: Vitamin D and depression - Larry Hoover » JLx, posted by JLx on November 2, 2004, at 12:07:55
> Hi Larry,
>
> From the "Supplements for brain fog" board,
>
> >I'll just make a summary statement here, but the 4000 IU recommendation is based on solid research, and it's quite a new finding. It takes a while for the facts to filter through into what we know.
>
> Yes, and often alternative med is on the cutting edge. I remember well how many years earlier I was reading about free radicals and antioxidants there before it hit the mainstream. And look at the medical establishment's refusal to pay attention to the guys who made the ulcers/H. pylori connection. My impression is that this might be one of those things, and if so, it could take years before we all "know different" and meantime we're setting our health back that much more too.I couldn't agree more. Linus Pauling, a two-time Nobel laureate, was vilified in some of the most unscientific and political acts I've ever seen in the scientific arena.
Here's a lovely essay on the subject.
http://www.internetwks.com/pauling/hoffer.html> > I think the oral toxicity of vitamin D is related to the bolus effect. What that is is the huge serum concentration spike that comes from uptake across the gut wall. Vitamin D synthesized in skin trickles out into the blood, via diffusion. The total amount made from acute sun exposure is not just suddenly dumped into the blood. It's the essence of a timed-release vitamin D repository.
>
> Ok, I'm not understanding this I don't think. I read that it only takes 15-30 minutes of sunlight to get 20,000 IU of Vit D (if Caucasian). You're saying that amount is in the skin and then trickles out slowly into the blood?Yes. Just as you'd get if you someone got vitamin D from a transdermal patch.
> Then once it's in the blood, the excess accumulates in the fatty tissue. When needed and not being supplied through the skin or diet, the body then draws it out of the fat.
There may not be any excess to store. It's hard to say, as there is a constant give-and-take between tissues and blood. It's called a complex equilibrium. There's a bidirectional transfer going on all the time.
> I still don't see the difference between the Vit D that's stored in the fat that originally derived from the sun or that which originates in the diet per food or supplement. What if you were in the habit, as some people surely are or were historically, of eating a lot of salmon daily while also getting a lot of sun? No danger, surely!
One of the differences might be free vitamin D versus bound vitamin D. Vit D is fat soluble, so it surely attaches to circulating lipoproteins, e.g. HDL and LDL. I'm suggesting that a high oral dose might produce an overload of free vitamin D, whereas vitamin D from dietary intake or from skin production might circulate only in the bound form.
> So, is there some difference simply in the supplemental form and what it does and how it's utilized later? That seems to me to be the crux of the problem and I haven't read anything to suggest that taking cholecalciferol is somehow different in the body other than as you say, a short spike as it's dumped rather precipitiously into the blood stream.
The toxic effects, if there are any, might be solely from the spike itself. That is my hypothesis.
> But again, surely that is not so different than eating that salmon while basking in the sun.
Maybe it is, as neither might produce surges in free vitamin D.
> And once it's in the fat, and NOT needed/drawn by the body as it must be for those who get a lot of sun day after day, then what?
Given that people in the sun do not get vitamin D overdoses, it is possible that production is down-regulated at some threshold concentration. Or, the body might be able to store much more of it than was previously realized. I lean towards the first explanation.
> This is interesting about obesity and Vit. D:
>
> http://www.cholecalciferol-council.com/obesity.htm
>
> "10. Obese subjects obtain lower 25(OH)D levels when exposed to ultraviolet light or when they take supplemental vitamin D.
>
> A. True.
> B. False.
>
> True. Obese subjects appear to deposit some their vitamin D in their excessive fatty tissue, thus impairing their ability to raise their 25(OH)D levels."
>
> So the more fat you have, the more of the Vit D that you do get, is deposited in the fat. I would think all that fat stored Vit D would be a kind of insurance against becoming deficient. But it sounds like it's the opposite from that and the other correlations he notes.It's more of a dilution effect. A non-obese subject might have ten pounds of adipose tissue. An obese subject might have 150 lbs. The net effect is to draw vitamin D out of the blood, as entropy demands that concentrations equalize across all possible boundaries.
> That compounds my confusion about this storage business and how it becomes toxic. A saturation point is reached? So then too much is in the blood all the time?Too much free vitamin D, is my concern.
> And perhaps this is the stupidest of questions, but what happens to the Vit D stored in fat when a person loses weight? Is it broken down instead of released when the fat stores themselves are used for energy?It redistributes among the remaining tissues. The process is slow, and is probably regulated so that free vitamin D levels do not surge.
> It sounds as if small doses of Vit D throughout the day would be the answer to the bolus problem. When physicians do supplement to bring up Vit D levels, they do so in pretty large doses of 10,000 IU. What do you think of that sublingual emulsified version? An advantage or problem in bypassing the stomach?Sublingual emulsified....hmmm. Emulsified in what, in particular?
Frankly, the best source would be e.g. fish liver oils, as the vitamin D would surely be associated with the appropriate carrier fats.
> > Did you catch note of the positive effects arising from a single oral dose of 100,000 IU? I recall seeing that last night, as I was skimming. It gives one pause, with respect to oral toxicity.
> >
> > Lar
>
> Yes, I notice also that the massive by-accident doses, sometimes huge and over a fairly long period of time, were apparently not irreversible.It just takes the body a little while to redistribute the vitamin properly. Water-solubles redistribute quickly. Fat-solubles take a long time.
> It's all very confusing. It sounds as if we've been scared a lot and thoroughly for no good reason.
>
> JLI agree with that conclusion, 100%. I don't know what to make of the deception, but it is intentional.
Lar
poster:Larry Hoover
thread:410247
URL: http://www.dr-bob.org/babble/alter/20041022/msgs/411682.html