I wanted to tell you about something I read recently. I'm curious as to if you have any insight. Andrew Weil has a large audience. His August 1999 newsletter (which will be compiled for this year's booklet) says:

"there's now evidence that 200 to 500 mg vit C a day is more than enough to saturate the body's tissues."...

Weil cites an April 21st 1999 JAMA article and an Am J Clin Nutr article by the Linus Pauling Institute as the reasons he's lowering his recommendation from 2 to 6 g/d to 0.2 to 0.5 g/d. He uses Linus Pauling's name (it's HIS institute, after all) twice to bolster his point.

So there we have it: the most popular vitamin proponent, the Linus Pauling Institute, JAMA, J Clin Nutr, National Institute of Health, and the National Academy of Sciences (the new RDA) all agree: less than 500 mg a day is needed for optimum health.

Here are the reasons I think they are wrong....

The inadequacy of the article can be seen by the following observations:

1. The article cites a 1997 article to claim vitamin C in gram doses has no place in the treatment of colds while ignoring a Feb 1999 article by the SAME RESEARCHER that claimed 2 g/day reduces the duration of colds by 26%. The abstract of that reference is included below. Pauling claimed vitamin C would have its greatest effect on the common cold when a gram was taken every hour instead of just once a day.

2. The article recommends an RDA of 100 to 200 mg/day based on arguments that are almost entirely theoretical instead of citing the many real world studies showing substantial health benefits from levels greater than 1 g/day (including numerous studies on specific diseases done in the 1940's and 1950's - see the 1971 book by Irwin Stone "The Healing Factor - Vitamin C against Disease").

3. By the article's own admission, it recommends an RDA of 100 to 200 mg/day based on faulty data manipulation. The authors chose to measure steady state blood plasma concentration after ingestion instead of actual concentrations because the calculation for actual concentrations was "too complex". From reading the text, one would think 60 umol/L in the blood is as high as can be possibly achieved (which results from ingesting 100 to 200 mg/d). However, by making an estimation of their lower graph in figure 3, the data indicates that if 1,000 mg were taken 4 times a day (the recommendation of several popular nutrition experts such as Dr. Julian Whitaker and Michael Murray), it would average out to about 180 umol/L. Surely a little more calculation (or even some estimating) would have been worth the effort to show a 3-fold increase!

4. The authors' blood and urinary data used to support their suggested maximum recommended daily amount of 100 to 200 mg/d is claimed to be better than data previously available. The JAMA article's data and arguments are 20 years old. Linus Pauling in his 1986 book "How to Live Longer and Feel Better" used nearly the exact same blood, urine, and absorption data (pp108-112) to address the exact same misunderstandings to show that 140 mg/d should be considered an absolute minimum value instead of a maximum. Pauling believed the optimum range of vitamin C for most people would be between 3 and 20 g/d.

5. The authors do not seemed bothered or amazed that their claims indicate humans need 10 to 100 times less vitamin C than almost every other animal on the planet (adjusted for body-weight). Gorillas get 20 to 40 times as much in their diet and the RDA-equivalent for monkeys is also about 20 to 40 times higher than the authors are recommending for humans. Why is the RDA set so low for humans and so high for monkeys?

6. The authors do not give any physiological explanation for why they believe humans are so unique among the animal kingdom as to find relatively small doses (1 g/d) of vitamin C "toxic". This size dose has never resulted in a human suffering an adverse health effect (other than those who are sensitive to it have temporary diarrhea). The article discusses increased iron absorption and oxalate production, but no case of a human being harmed is reported. The article's suggested "toxic" level for humans is approximately the bare minimum needed by all other animals. Other large mammals sacrifice 2% to 4% of their daily food energy to make vitamin C in concentrations 10 to 20 times higher than what the article considers "toxic", showing that not only is it not toxic, but it's more important than having a little extra food!

Scott Roberts
heelspurs.com
December 2, 1999

Editors Comments: Although the Vitamin C Foundation stands firmly behind the long-time recommendations of Linus Pauling, that the minimum optimum oral Vitamin C intake in humans is in the range 3-4 gm, we welcome the small step in the right direction of the Levine group at the National Institutes of Health (NIH). Their recommendation, to increase the U.S. RDA from 60 mg to 200 mg of vitamin C, is long overdue. Although even this small recommended increase will meet resistance, if it were to be adopted by the Nutrition Review Board at the National Academy of Science, the health and well being of vast numbers of people would significantly improve.

As far as the specific argument of tissue saturation, we agree with Scott that there must be a flaw in the Levine argument. First, consider animal metabolisms. Almost uniformly, endogenous vitamin C production is in the multi-gram range. Most higher-order mammals, for example, produce the equivalent to 9-11 gm for humans in their livers. This extraordinarily high amount enters the blood stream in its entirety. (This is the reason Pauling himself took 18 gm -- he estimated that about half what is taken orally is lost through excretion.) Stone's argument, and it is a good one: Why do almost all animals (except a few high order primates) produce that much vitamin C if it is not necessary?

Then there is the Cathart Bowel Tolerance phenomenon. Cathcart has shown that almost all humans can tolerate 4 gm vitamin C per day without diarreha. Yet individuals under stress can tolerate orders of magnitude more vitamin C, sometimes 100 gm or more per day. These high amounts are absorbed, and as one who has experienced a 150 gm/day bacterial infection, the question becomes: What is the body doing with these extraordinary high amounts of vitamin C during periods of stress? More importantly, what happens to tissues that do not have enough vitamin C stored to meet demand because intake has been limited to 200 - 500 mg per day?

Orthodox medicine is making slow progress, but has yet to address these two issues. It is possible that adequate or optimum vitamin C intake is much higher that 4 gm per day, perhaps closer to Pauling's own 18 gms per day. Dr. Robert Cathcart, III, MD, reportedly consumes 60 gm vitamin C daily.

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