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 questions on studies regarding vit C dosage 
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Post questions on studies regarding vit C dosage
Hello all,

I'm new to these forums and to the vitamin C scene in general. So I
have a very basic question about vitamin c dosage for healthy people.

I've read in the Linus Pauling Institute that a very simple
test is used to determined how much of the ingested vitamin C consumed
stays in the system. That is they measure the intake and then they
measure how much is excreted from the body. Most people can absorb
approximately 200 mg. Meaning that the rest comes out in the urine.

Are there any studies that have demonstrated that on healthy
individuals (ie those who don't have the flu) are capable of retaining
in the body multi-gram dosages of vitamin C.

I know some studies have shown increased retention of up to 1,000
grams in adults with the flu, but nothing greater than this and never
this high on people who are not sick.

I'd appreciate any links that point towards studies of this nature.

Sincerely, Jonathan


Wed Jul 05, 2006 3:43 am
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Post NIH Studies
The test may be very simple, however, the real question to ask is when did they take the measurements? The studies done by Dr. Mark Levine at the NIH clearly show a half life of approximately 30 mintues. So within that 30 minutes, the amount of ascorbate in the blood can be very high. However, Levine strangely based his recomendation of 200 mg on a measuerment taken 12 hours after ingestion! So of course, the blood levers were greatly reduced. But if you take divided doses of vit C throughout the day, you can in fact maintane a high level of ascorbate in your blood stream. For reference, see [url="http://www.lulu.com/ascorbate"]Ascorbate: The Science of Vitamin C[/url] by Drs. Hickey and Roberts. It goes into detail on Levine's research and proposes a theory of dynamic flow to explain the action of vitamin C in the blood stream.

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Wed Jul 05, 2006 8:30 am
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Post Megadosing
Hi,

I think in addition to the clinical results, you should also pay attention to the number of people on this site who have been megadosing for years and who have normalized their cholesterol, stripped plaque from their arteries, regulated their arrhythmia and handled multitudes of health problems by using very large doses of Vitamin C. If you go to the Vitamin C Foundation home page and look up Dr. Cathcart you can find he will show you of results on his patients over many years using very high doses both oral and intravenous. Also if you read How to Live Longer and Feel Better by Linus Pauling you will be given hundreds of clinical reports on this efficacy of Vitamin C.

Salud
John :D


Wed Jul 05, 2006 11:01 am
Post 
Hello all,

Bobber wrote:

The test may be very simple, however, the real question to ask is when did they take the measurements? The studies done by Dr. Mark Levine at the NIH clearly show a half life of approximately 30 mintues. So within that 30 minutes, the amount of ascorbate in the blood can be very high. However, Levine strangely based his recomendation of 200 mg on a measuerment taken 12 hours after ingestion!

This concerns blood serum levels. I was asking about the difference between intake and the amount excreted without being metabolized.

On the Main site to which this forum belongs, on the FAQ, it reads:

The Hickey/Roberts Dynamic Flow findings indicated that the half-life of vitamin C in the blood stream is 30 minutes, and that 500 mg every 4 hours keeps the blood at the highest concentrations all day long.

Five hundred milligrams every four hours amounts to three-thousand milligrams per day and according to the above, this amount is determined by blood serum level.

The question I was asking was, are any studies that establish the maximum amount a healthy person will metabolize per day? – or an average thereof. This is done by measuring the intake and the excretion of un-metabolized vitamin C. For example, lets say I take five-thousand milligrams per day, and in the urine it show that I’ve excreted two-thousand milligrams without using it. Then that would mean that my body has absorbed and metabolized three-thousand milligrams. If I then proceed to take ten-thousand milligrams per day it will not make a difference in the amount I absorb, I will simply pass the excess ascorbate in the urine.

Johnor wrote:

I think in addition to the clinical results, you should also pay attention to the number of people on this site who have been megadosing for years and who have normalized their cholesterol, stripped plaque from their arteries, regulated their arrhythmia and handled multitudes of health problems by using very large doses of Vitamin C.

This is foremost in my mind, but it is a valid question to ask if those same results would have been obtained with a significantly lower dosage. I’m assuming that by large doses you are talking in the neighborhood of 15 grams per day or so.

Sincerely, Jonathan


Wed Jul 05, 2006 5:32 pm
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Post Excellent Question
Thank you for asking. (I hope we can get an answer from either Dr. Hickey or Dr. Roberts, I know they are both busy, but theirs would be the most authoritative answer.)

Really an excellent question and hits the nail on the head.

Here is what we (think we) know.

1. The maximum blood concentration from oral intake is achieved between 150 mg and 200 mg and that maxium blood level is approximately 15 mg/dl. (According to Pauling, this is a linear relationship up to 150 mg so that 10 mg creates a blood level of 1 mg/dl, 20 mg intake leads to 2 mg.dl, etc.) When the blood levels exceed 15 mg/dl amount, the kidneys will begin pumping vitamin C out of the blood. This has created the FALSE idea that 150-200 mg is the maxium level where tissues are "saturated". Pauling and Hickey/Roberts explain why this idea is FALSE. (If anything, we can say the blood becomes saturated, but this may have little connection with how "saturated" trillions of cells that can receive ascorbate are.)

2. Both Lewin and Pauling estimate that more than 50% of the ascorbate taken by mouth is biologically unavailable (the vitamin breaks down in the gut before entering the blood stream.) Not sure how this plays with #1, but it is possible that we can argue for at least 300 to 500 mg to account for vitamin breakdown before the kidneys begin pumping.

Also don't know if this is measured as vitamin C in the urine or not.

3. Cathcart thinks that only the vitamin C that is NOT absorbed, e.g. that which makes it all the way to the rectum, causes diarrhea. Ergo, if you take 9000 mg at one time, (as I do), and do not get diarrhea (I don't) then some between 4500 and 9000 mg have entered the blood stream.

I haven't read the Hickey/Roberts book in a while. In my case, I've been taking this much for 20 years, and I have symptoms that I need more C every 12 hours (tickle in the throat, start of congestion). So 9000 mg lasts 12 hours in my body/blood before it is all expelled.

#4. Animals without the GULU defect produce 5000 to 10000 mg daily - 24/7 - adjusted for body weight, directly into the blood. This "dynamic flow" has many functions, and is roughly the equivalent of 500 mg per hour by mouth. (Do we lose half? etc.)

#5 Frank scurvy can take about one month. S. Lewin said the half life of vitamin C in the tissues is about 27 days. That means that without ANY vitamin C, there would still be some vitamin C expelled as it drains from tissues for 27 days.

#6 The rebound or discontinuation effect has to do with enzyme reactions that convert extra ascorbate into other substances. Obviously, this increases the requirement as a person increases their intake.

Back to your question, I don't know if we can simply measure how much is expelled, versus how much stays in the tissues, because one of the properties, the dynamic flow, is obviously to rid cells of toxins as C flows in and out. You could say that the animals "lose" most of the ascorbate they produce in the urine, and I'm not sure if there is any test that tried to measure the difference. That is why members have pointed out that you should listen to your body - how well (or bad) you feel.

I'll clean this up later.

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Owen R. Fonorow, Orthomolecular Naturopath


Wed Jul 05, 2006 7:48 pm
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Post Megadosing
Hi,

I'd like to second what Owen said about the 9,000mg of C. I have tried lesser doses of C but the 9,000 does hit the spot. Almost immediately my sinuses dry up and I'm breathing freely and feeling more limber. I also take another dose of 9,000 in the late evening. If I back off from these amounts I start getting symptoms back.

Also note that the medical establishment does resist megadosing like the plague. Linus Pauling mentioned one doctor who told him he had tried megadosing on his patients and it didn't work. When asked how much he used, he replied that it was in the low to mid 100mgs. The physician added that he of course wasn't going to give his patients the ridiculous amounts that Pauling recommended. Hilarious! This same mindset governs most of the thinking in the medical community. 15,000 mg is darned scary to some people.

Salud,
John :D


Wed Jul 05, 2006 8:35 pm
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Post Sublingual Ascorbic Acid
If you can take the sourness,you would be surprised how even 200 milligrams of vitamin C,mouth absorbed,works.I think you get almost 100%absorption,whereas, G.I. tract absorption is much lower.Sincerely,Van

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Thu Jul 06, 2006 3:52 pm
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Post Sorry
Jonathon25 - we have to scrub the users daily and we made a mistake and scrubbed you!?! Very sorry about that! Please rejoin and continue the interesting conversation. (We no longer have your email, or we would have handled this privately.)

(As background, several automated programs (apparently) create forum users that advertise porn web sites, etc. Instead of waiting for these people to post their advertisement, we have been proactive. However, we made a mistake in your case.)

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Fri Jul 07, 2006 7:19 am
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Post When you rejoin
Jonathon25, when you rejoin let us know (link) where the LPI says that you can measure how much is "absorbed" by checking the urine?

Quote:
Most people can absorb
approximately 200 mg. Meaning that the rest comes out in the urine.


Actually, if not absorbed - the rest would come out in the feces, (but as we pointed out, Cathcart says that you get diarrhea in that case.)

So 9000 mg can be fully absorbed in at least one person (myself) and I guess your question is how much of that enters cells and how much is filtered out of the blood by the kidneys and expelled in the urine? Is that what you are asking?

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Owen R. Fonorow, Orthomolecular Naturopath


Fri Jul 07, 2006 7:23 am
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Post 
Hello all,

I am Jonathan25, I've logged in under this new account before I'm having difficulties with the old one.

ofonorow, here's a link to the page in the Linus Pauling Institute which expalins how absorption is measured:

http://lpi.oregonstate.edu/infocenter/v ... Cform.html

Look at paragraph number 4 specifically.

Sincerely, Jonathan


Sat Jul 08, 2006 1:06 am
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Post Assumptions
Quote:
There have been few studies conducted to determine the efficiency of ascorbic acid absorption in humans. Differences in the extent of its absorption among individuals may contribute to the outcome of clinical trials. Ascorbic acid absorption in four subjects was investigated from several oral dosage forms containing 1 g of the vitamin (solution, tablet, chewable tablet, and timed-release capsule. Approximately 85% of an intravenous dose was recovered in the urine as ascorbic acid and its major metabolites. In contrast, only approximately 30% of the dose was recovered from the solution and tablet forms. A considerably smaller fraction of the dose (approximately 14%) was recovered from the timed-release capsule. There was considerable intersubject variation in ascorbic acid absorption and there appeared to be good and poor absorbers of the vitamin. Consideration should be given to the influence of the extent of ascorbic acid absorption on the results of clinical trails.


The assumption that was made in this study (reference 4) is that if it doesn't come out in the urine (spillage) it was not absorbed.

In our experience, if the vitamin is not absorbed, the subject experiences diarrhea as the vitamin reaches the rectum.

An alternative explanation is that the vitamin was better utilized by the body and not expelled or "spilled" into the urine. For this is what we would predict, that a time release, slower release, would create ascorbate levels in the blood below the kidney threshold.

So from what we can infer from the abstract, it seems likely that this study is showing a benefit of timed release vitamin C. All the vitamin c was "absorbed" but less of it expelled.

And this is a good illustration why Pauling's method - of reading and anlayzing the body of the study, and only then comparing his conclusions with the authors - is better than simply accepting study conclusions at face value.

p.s. By the way, the next study (ref 5) seems to bear out my point. When measuring blood levels, (rather than urine expulsion), there was no difference between tablets and timed release.

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Owen R. Fonorow, Orthomolecular Naturopath


Sat Jul 08, 2006 9:36 am
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Post 
Hello all,

You'll notice that in both references low dosage (by megadose standards) was utilized. That's the reason for which I opened this topic, to see if there had been any studies regarding the absorption of megadose 10 + grams of vitamin C and how it differes from lower dosages like 3 grams etc.

Sincerely, Jonathan H


Sun Jul 09, 2006 5:12 pm
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Post Excretion
Jonathon,

And our response points out that understanding vitamin C's role in the body it is not as simple as measuring excretion. Modern medicine generally avoids high dose vitamin C in their studies, but Pauling discusses the so-called "loading tests" that were developed shortly after vitamin C was isolated in the 1930s on pages 91-94 of the new HOW TO LIVE LONGER and Feel Better (2006).

The loading test "gives a subject a certain amount of vitamin C, by mouth or injection, collecting the urine for the following six hours and analyzing it for ascorbic acid."

Quote:
"If a large amount of vitamin C is taken, 62 percent of the amount that enters the bloodstream is excreted in the urine, so that only 38 percent remains in the body to carry on its valuable functions. It is, however, good to have vitamin C in the urine. It protects against urinary infections and also against cancer of the bladder." (Pg. 91)


Pauling discusses the idea that there are low, medium and high excretors of vitamin C, and that interestingly, schizophremics are low excretors (meaning they seem to be able to utilize higher amounts without reaching the kidney limit) Pauling provides two reasons why people may be "low excreters":

Quote:
"A person who eliminates a smaller fraction of the ingested ascorbic acid may do so either because he or she has been living on a diet containing an insufficient quantity of the vitamin, such that the tissues are depleted, or beccause some biochemical abnormality of his or her body operates to remove ascorbate from the blood serum very rapidly, perhaps by converting it rapidly into other substances."


Again, you are using the word "absorption" and below bowel tolerance http://www.orthomed.com/titrate.htm it is likely that ALL the ascorbate ingested, and not broken down in the gut, is "absorbed."

The argument is not about absorption, but utilization. Nutritionists used to argue that any amount over 200 mg is simply excreted and thus wasted. This may be partly true, but we are not able to perfectly emulate what animal livers make 24/7. Animals continuously make smaller amounts. Humans, mainly for reasons of convenience, generally take larger amounts less frequently. The more we take, the longer it stays in the blood stream (per Hickey/Roberts Dynamic Flow)

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Mon Jul 10, 2006 7:33 am
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Post Urine Is Modified Blood
Years ago I remember reading this somewhere.Possibly urine/ascorbic acid levels show serum levels of A.A.This ,someone might want to check out.Thanks,Van

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Mon Jul 10, 2006 4:50 pm
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Post Re: Excellent Question
ofonorow wrote:
I hope we can get an answer from either
Dr. Hickey or Dr. Roberts ...


It would be interesting to search for SVCT2 (one of ascorbate transporters)
in bladder endothelium. I couldn't find any information about presence of
this protein in bladder, maybe they know something about this?

If SVCT2 is present in bladder cells, it would be interesting to find out
is there any uptake of vitamin C from bladder.


Tue Jul 11, 2006 4:39 am
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