Durk Pearson & Sandy Shaw®
on the Importance of ...
on Vitamin C
lthough it's difficult to remember, vitamin C was once at the barricades where it carried the battle flag of dietary supplements in the war initiated and sustained by the misguided opposition. Championed by Nobel Laureate Linus Pauling - a veteran of the Nutrient Wars - vitamin C's status in the world of scientific literature is entrenched, despite the implications of a recent study, in the journal Nature, referring to DNA damage caused by modest amounts of the vitamin. Yet judging from the media response, you would think an old powder keg had been set off. Far from it, if you read on. The fizzled explosion seems more like the work of the firemen in the novel Fahrenheit 451, not trying to put out fires but to start them, and in home libraries of all places!
The fire squad in the real world are the quackbusters - forever rummaging for quack doctors, quack medicine, quack theories - striving not to promote research but to stop it. In spite of the pathetic nature of this limp-minded assault, vitamin C remains one of the most important supplements you can take. Durk & Sandy offer their opinions about the co-operation of both the water-soluble and fat-soluble forms of Vitamin C in the lipid and aqueous tissues of the body.
DURK: Most vitamin C tablets on the market are ascorbic acid. And ascorbic acid is a fairly strong acid that can be irritating to your stomach. If you hold one of those ascorbic acid tablets in your mouth and let it dissolve against your cheek pouch and gum, you'll end up with an acid burn. Hoffmann-La Roche's calcium ascorbate has high stability. It is far less susceptible to auto-oxidation which can be caused by very small amounts of trace metals such as iron, copper or manganese. The standards for Hoffmann-La Roche's ascorbate consider residues of these auto-oxidation catalyst metals greater than a few parts per billion unacceptable. So it is definitely the best in terms of very low levels of those pro-oxidant substances. Hoffmann-La Roche's calcium ascorbate remains white longer than most other company's ascorbic acid, meaning it is very stable and does not oxidize perceptibly over long time periods. (Ascorbic acid is inherently more stable than the non-acidic calcium ascorbate.)
Calcium ascorbate is not very likely to irritate your stomach the way ascorbic acid will if you take it on an empty stomach. I wouldn't expect most people to have a gastrointestinal problem taking 600 mg of ascorbic acid with a meal, although there are a few that do. But calcium ascorbate can be taken on an empty stomach without causing acid indigestion. In addition, ascorbyl palmitate is a very powerful anti-oxidant synergist. Unlike ascorbate which is water soluble, ascorbyl palmitate is a fat soluble form of vitamin C, thereby providing coverage in the fat tissue of your body. Regular vitamin C (ascorbate or ascorbic acid) can't even dissolve one part per million in fat. But with ascorbyl palmitate it dissolves freely in fat. In addition to being a very powerful anti-oxidant synergist, it also helps block promotion in epithelial cancer formation.
A few years ago, at a National Cancer Institute meeting, there was a report on ascorbyl palmitate, characterizing it as a very powerful anti-promoter of cancer. Cancer is developed in stages. You have initiation, where you have genetic damage that's been done. Just about everybody's been exposed to combustion tars or to ultraviolet light. So at least some of our cells have been initiated. What happens after that is a process called promotion. If you block that promotion, you don't end up with the initiated cell going all the way to cancer; it's abnormal, but it doesn't become cancerous and divide and divide and divide. Ascorbyl palmitate was found to be effective at blocking promotion in a mouse skin cancer model.
WILL: I believe the study found it to be something like 40 times more effective than ascorbic acid in that regard.
DURK: Yes. And I suspect a part of that is because it is fat-soluble. It can dissolve in the fats in the skin where a lot of oxidation can take place. And remember, the skin is the second fattiest organ in the body after the brain, and of course your fat deposits. I've been surprised how few supplement companies have caught on to it. We've looked at the data using vitamin C as a synergist in preserving foods where you have vitamin E or BHT or other antioxidants present.
WILL: Can you talk a little bit about the relationships between vitamin E and vitamin C? Where is vitamin C in the whole chain of free radical neutralization?
DURK: Different free radicals react at different rates with different antioxidants and different environments. And if that sounds complicated, it is. And there's no way for me to simply answer your questions. If you want to do a literature search, you'll find all sorts of literature of experiments that were done under particular conditions with particular solvents and with particular types of fats and antioxidants present. But that's not necessarily or exactly what you're going to have occur in your body.
WILL: What about the study reported on in a recent issue of Nature using 500 mg of vitamin C that the press ran through the gauntlet claiming DNA damage?
DURK: That was a very brief report. Unfortunately, they didn't go much into their methods. All the non-scientific press talked about - it was a letter, not an article - was the increased amount of oxidation in one DNA base. Oxidized DNA bases are a general measure of damage by free radicals. What it didn't mention is that vitamin C reduced the amount of oxidation in another base, cutting it roughly by one half. There appeared to be a slight net reduction in the total number of bases that were oxidized and, furthermore, the total amount of oxidation was decreased.
SANDY: There's been a lot of criticism of this letter, particularly with respect to the methods and lack of description of the methods that were used.
DURK: Hopefully, they'll publish the study as an article.
When a DNA base is not properly repaired it could cause a mutation. The press misinterpreted these results. In the study, they didn't give these people any additional vitamin E to help handle the increase in the amount of vitamin C ingested, an increase by 10 times assuming that they weren't taking any supplements before, or were at most taking an RDA level supplement.
SANDY: Never-the-less, it must be noted that Dr. Bruce Ames and Dr. Lester Packer who have performed a great deal of research with oxidized nucleotide bases have criticism of this particular study; they don't think that it's being interpreted properly. I have not seen their full comments in publication yet. But I think that this is something to watch for because these two people have probably had more experience with the use of this technique than anybody else.
DURK: The technique is measuring oxidized bases as a result of free radical damage. In the meantime we've just got to wait and see what happens.
WILL: In increasing the amount of ascorbate that one takes, what kind of benefits can be expected? It's not a linear increase.
Ascorbyl palmitate was found to be
effective at blocking promotion in
a mouse skin cancer model.
DURK: No, in fact the blood level increases more or less as the logarithm of the amount of ascorbate that you take. To double your blood levels takes roughly 10 times as much vitamin C. And to double them again takes another 10 times as much.
WILL: How does one determine the top level, the optimum level?
DURK: That's a very good question. Again, that's not something that is really known. It's going to vary from human being to human being. Something that is optimized for one system in your body isn't necessarily optimized for another system. You may breathe out the minimal amount of ethane or pentane (free-radical oxidation products of polyunsaturated fats) at a different level from which you have the minimal total excretion of oxidized bases: oxoguanine plus oxoadenine (markers of DNA damage to guanine and adenine nucleotides). Again, this is simply not known.
WILL: What about the comments often heard that the maximum amount of ascorbate in serum is reached with a relatively small amount of vitamin C?
DURK: That's actually not true. Beyond a certain point, you get much lower serum increases for higher increases of vitamin C dosage. Like I said, to double your vitamin C level takes very roughly an order of magnitude more of C; to double it again takes another order of magnitude more. I don't mean twice more, I mean an order of magnitude times an order of magnitude.
WILL: What about the ideal ratio between ascorbate and, say, vitamin E? Should one maintain the same ratio of vitamin E to C, if one takes more vitamin C and more vitamin E?
Typically, the optimum ratio of vitamin C
to vitamin E is somewhere between
4:1 and 8:1 for long-lived type animals.
DURK: It's in the reasonable ballpark. Again, you're going to find that there are substantial individual variations. Typically, the optimum ratio of vitamin C to vitamin E is somewhere between 4:1 and 8:1 for long-lived type animals. This is, again, something which I'm sure is going to vary from person to person.
SANDY: It'll also vary under different conditions. For example, if you're exercising, you're under a lot of additional free radical stress. You're probably going to have a different ratio of vitamin C to vitamin E in your blood stream. And you'll also have a different ratio of vitamin C to vitamin E in your lungs than you do in your blood stream. The different tissues don't all have the exact same amount of C and E either. It's extremely complicated.
DURK: If you have more fat, you're going to have more vitamin E in your body. Whether or not you need more in your diet I don't know, but it seems plausible you might. If you're smoking, both your C and your E are going to go down. I believe that the C goes down more than the E.
DURK: These are all questions that are answerable in principle. But the cost of doing the necessary experiments is very high. What you have here is an art, not just a science. If you have millions to spend, you can make measurements on large numbers of people. And even then, it's going to be an art of deciding what's important. One study might minimize the total excretion of oxoadenine plus oxoguanine. While another study might minimize the amount of pentane and ethane that you're exhaling. And yet another could minimize the amount of abnormal disulfide cross links in a particular protein. These would all be very costly studies.
SANDY: There are a lot of good tests to measure your oxidative activity.
DURK: And what's best for one organ is not necessarily best for another. There's an art to nutrition as well as science. And I think that there always will be.
WILL: A question that I've heard many, many, many times goes, "I'm a woman, I weigh 120 lbs. How much vitamin C should I take? Should I take about half the amount of somebody 200 lbs should take?"
DURK: Again, I think it would probably be more than half the amount. I would suggest scaling it on the basis of the amount of food that they eat.
WILL: Oh, I see; it is a complicated process.
DURK: Assuming that they have similar diets. Obviously, if a person has a lot of polyunsaturated fat, they're going to need more anti-oxidants in their diet.
And what's best for one organ is not
necessarily best for another. There's an
art to nutrition as well as science.
And I think that there always will be.
WILL: That makes sense; there are many individual factors to take into account.
DURK: In general, when you're dealing with nutrients, you're better off scaling doses on the basis of the amount of diet consumed rather than on the basis of your body weight. In fact, in experiments where a prescription drug dose is individualized for each subject, these doses are scaled on body surface area of the skin.
That's how you lose body heat and that's what determines how much food you eat. Thus the body surface and the amount (calories) of the food consumed scales very well together. They correlate very well. This concept is what's usually used for adjusting the dose of everything from prescription drugs in human experiments to both artificial and synthetic antioxidants in mouse experiments.
WILL: Interesting. Are there any benefits to be derived from taking high levels of fat- and water soluble vitamin C that you would not normally obtain from lesser amounts?
SANDY: Antioxidants work together and we know that under conditions of oxidative stress, it is usually vitamin C that provides the first level of defense. Once vitamin C is depleted, then such things as lipid peroxidation tend to drastically speed up.