Don't you just love it when the traditional press just takes off when they find a supplement might cause a problem? Vitamin C is not killing hundreds or even tens or possibly even one person, unlike the over 100,000 people who are killed by prescribed drugs every year.

The key to understanding this story which received huge publicity last week involves focusing on the following statement: "Vitamin C may interfere with radiation or chemotherapy treatments." The word is MAY. There is no evidence presented that it does cause a problem, only a concern regarding a pathway in cancer cells that was found that appears to be similar to vitamin C.

This is not an area I have studied, and the truth may very well be that vitamin C is a problem. I don't know. However, I suspect it does not and the concern is being blown out of proportion. However, even if it did, the concern is only in the traditional paradigm treatment of cancer involving chemotherapy. Vitamin C may actually enhance cancer treatments involving more natural approaches.

The one thing that is clear is that diet, and especially the typical American diet, alone is usually not sufficient to supply the nutrients necessary for overall good health.

While most experts agree that nutritional supplements are vital for a variety of illnesses and age-related problems, vitamin and mineral supplements can also help to maintain optimal physical and psychological health, promote longevity, and prevent chronic disease.

Even so, too much of anything - including vitamins and supplements - can be toxic. The key is moderation, and common sense. Anyone currently under medical care, taking prescription medications, or having a history of specific problems should always consult with a professional health care provider (one knowledgeable about diet and supplemental nutrients) before making any changes in diet or lifestyle.

In 1998, a widely publicized study in the journal Nature linked daily doses of 500 mg of vitamin C to DNA damage. The results and methodology of that study have since been criticized, but many medical experts remain skeptical about pumping up the intake of vitamin C.

A later study, published in the September 15, 1999 issue of Cancer Research, still didn't have clear answers on the role vitamin C plays once it reaches cancer cells.

One of my previous newsletters in 1998 cited an excellent rebuttal to the Nature vitamin C and cancer study.

The following material is reprinted from an article by Steven Win. Fowkes in Vitamin Research News April May 1998 12:5-14.

It addresses the issue very precisely. It is already in my 1998 newsletter but not yet converted to the new format which is why I decided to post it again.

Enter your e-mail address and click on the Subscribe button:

A recent letter to the editor in Nature stated that researchers have discovered that 500 mg dosages of vitamin C may cause damage to genes. Although the study is real, the conclusion that vitamin C is dangerous is unwarranted by the evidence presented.

Of about 20 types of DNA damage that have been documented so far by scientists, only two types of DNA damage were measured. One increased while the other decreased. What does this mean? We really can't say, for several reasons.

First, the increase in 8-oxoadenine levels (a marker of damage to adenine "A"nucleotides) was offset by a decrease in damage to 8-oxoquanine levels (which is a much better-researched marker of DNA damage to guanine "G" nucleotides). With offsetting trends, the net effect is not clear.

Second, DNA damage is an incredibly complicated process that is balanced by DNA repair mechanisms. According to estimates, each cell in the body can be expected to suffer approximately 100,000 DNA-damaging events per day. This suggest that DNA repair is an extremely robust and vitally important process to consider.

DNA repair enzymes slide along the DNA strand scanning for signs of damage. DNA is composed of A-T and C-U base pairs which are strung together in a doublestranded spiral called a helix. When these repair enzymes find an oxidized adenine (A) or guanine (U) nucleotide, they snip it out (the C and T bases remain intact to maintain the structural integrity of the DNA during repair) and an unoxidized (normal) adenine or guanine is put back in its place.

The snipped out oxidized adenine and guanine are therefore markers of both DNA damage and DNA that has been repaired. Fundamentally, we are only interested in DNA damage that is not repaired. It is the unrepaired damage that is going to interfere with protein and enzyme function.

Third, we need to know the sites of damage because there are parts of DNA that do not get transcribed into proteins. These DNA sequences are either introns (which are snipped out during transcription) or initiation (control) sites which serve to activate and deactivate the transcription of "down-stream" DNA. Some of these initiation sites are now known to contain iron, which provides a clear and well known mechanism by which vitamin C can damage DNA.

Vitamin C reacts with ferric iron, oxidized iron, to form ferrous iron, reduced iron. Ferrous iron reacts with hydrogen peroxide to form a hydroxyl radical, a potent oxidant and free radical. Hydroxyl radicals are not only powerful, they are extremely unselective. In other words, they tend to react with the first thing they bump into.

Scientists have known for many decades that extracted DNA has iron associated with it, but they didn't know whether it was naturally present in native DNA or if it was an artifact of the chemical extraction process used to isolate the DNA. Now we know that the iron in DNA is there by design. It is actually imbedded in the center of the DNA double helix at certain loci (DNA sites) where it serves as an oxidation sensor to activate DNA in response to oxidative stress.

Because iron is bulky, it distorts the outer shape of the DNA helix. This distortion depends on the oxidation state of the iron. Under reducing (non-oxidized) conditions, the iron is present in the ferrous state and the DNA helix is fairly tightly wound around the iron atom (it only bulges slightly from the iron "nugget" imbedded inside). But when the iron is oxidized to the ferric state, it opens it up so that it is more easily expressed (i.e., transcribed into RNA and then into proteins).

What proteins are expressed?

Antioxidants! Thermal shock proteins! These may include enzymes like SOD, catalase and glutathione peroxidase, plus countless other proteins that help mobilize and regulate the antioxidant defense system.

The ability of DNA to "sense" free radicals and oxidizing conditions is an essential aspect of our ability to maintain homeostasis (biological stability) and adapt to stress (environmental change). The fact that there may be temporary damage to DNA is a trivial price to pay for enhanced adaptability and increased survival.

Although much of the research into iron-DNA mechanisms is still hot off the press, we do have some idea how the DNA interacts with iron. In its activated state, the ferrous iron-DNA complex can react with vitamin C and hydrogen peroxide to produce a hydroxyl radical which can (and apparently often does) attack the DNA at the iron-binding site.

Remember, hydroxyl radicals are highly unselective and tend to react with the first thing they hit. Since the iron-binding site is especially rich in A-T base pairs, it makes perfect sense that more damage would occur to A and T residues than C and U residues. In fact, I would be quite surprised if the researchers did not know about the iron sites and the increased proximity of adenine nucleotides before they conducted the study.

It would be a serious mistake, however, to presume that this specific damage will have any long-term adverse implications for cells, organisms or people. DNA repair enzymes, like antioxidant enzymes, are readily inducible (produced on demand). I wouldn't be surprised to discover that DNA repair enzymes are downstream of iron sites and thereby activated and transcribed along with antioxidants.

I can only conclude that until we know what damage is or is not being repaired, we cannot even begin to predict whether this specific effect of vitamin C on DNA would be expected to be positive or negative.

Since there are plenty of studies which show vitamin C to have a significant genome-stabilizing effect overall,2 I am not reducing my intake of vitamin C.

The Political Dimension

The same study in the U.S. press (the San Jose Mercury News). In this version, the helpful voice of Victor Herbert, M.D., was added to those of the researchers at Leicester University where the study was done. For those unfamiliar with Dr. Herbert, he is a notorious quack-buster, fostering vehement anti-vitamin rhetoric in the United States about any danger, real or perceived, from dietary supplements.

The eminent Dr. Herbert's involvement suggests that there may be an overt political agenda behind the publicity. In other words, why would a relatively obscure indeterminant finding generate such massive world-wide publicity? The answer may be found in the article in the London Times which stated, "The government has moved to limit the use of vitamin B6 because of safety concerns. Jeff Rooker, the Food Minister, had already announced that vitamin C was his next target."

Aha! The Food Minister needs a perception of danger to justify his policies. If danger is not an issue in real life, extrapolated from a superficial and inadequate scientific finding to create some perceived danger. As long as the public is scared, they will let politicians and bureaucrats do anything.

The political alignment between Jeff Rooker, the vitamin-prohibiting British Food Minister, and Victor Herbert, the quintessential U.S. quackbuster and antivitamin ideologue, provides a clear rationale about how this minor study was transformed into worldwide news.

Years ago, Victor Herbert hit the news with warnings about the dangers of vitamin C towards vitamin B12 absorption. Extrapolating from test tube experiments, Herbert postulated that high-dose vitamin C supplements would interfere with B2 assimilation and function. He was wrong. People taking high-dose vitamin C, even for multiple years, did not show any signs of B2 deficiency. Such is Herbert's track record crying "Wolf, wolf!" Test-tube experiments are a far cry from real life. Extrapolate such results at your own peril.

1 Ames, BN, Uold, LS. Endogenous mutagens and the causes of aging and cancer. Mutation Research 250(1-2):3-16, SeptùOct, 1991

2. Fraga, CU, et al. Ascorbic Acid protects against endogenous oxidative DNA damage in human sperm. Proc Nati Acad Sci USA 8 8(24): 11003-1 1~006, 15th Dec, 1991.