Antioxidants and Cancer

Antioxidants are rapidly losing their luster. Oxidants have been shown to have cancer fighting properties, and taking antioxidants has the unintended consequence of protecting the tumor.Free radicals

It’s never quite clear how things will turn out when we meddle with Mother Nature. The largest unwelcome surprise is surely trans-fats, man made oils used as a butter substitute known as margarine. Perhaps you have had some. For several decades, trans-fats were used as the main oils in most packaged food, primarily because of their nearly indefinite shelf life. It is estimated that in its heyday, it caused 30,000 premature deaths per year in America alone. Clearly something went badly wrong.

The protective effect of antioxidants was well established by 1980, at least in a marketing sense. The research would take another 25 years. In the meantime we were encouraged to wolf down an alphabet soup of vitamins daily, with the assurance that it could do considerable good and couldn’t possibly do any harm.

A simple multi-vitamin was way too weak for what we seemed to have had in mind. Megadoses of C, B, E and so on were the surefire ticket to health.

Do no harm. Eventually some people started doing decent studies on the effects of vitamins. What is decent? We mean here, that rather than following a particular vitamin and its effect on a specific cancer, that the vitamin’s effect on all-cause mortality was considered. Why is this better? Simple. Suppose huge doses of a vitamin reduced a certain cancer. This could well be the case. That alone is not enough. We want to know if it caused other cancers to increase, or if it caused some other problem. Hence, by choosing all-cause mortality, we can capture all the effects at once. And with all cause mortality, there is never any dispute over the diagnosis. Death is a clear endpoint.

So what happened? The entire alphabet soup, with the sole exception of vitamin D (no definitive data yet on D), was either neutral, or, increased mortality. This was a most unexpected result. Furthermore, all the other supplements, selenium, for instance met the same fate.

The message was loud and clear, or at least it should have been: anti-oxidants are not the answer. But what could have gone wrong? Oxidants damage cells. Oxidants are called free-radicals. Surely this must be bad.

Of course, it turned out that like everything else, oxidants are regulated by the body, and used for a variety of purposes. Any attempt to reduce them fouled things up.

But now things seemed to have tilted in the other direction. There now seems to be a particular benefit in suppressing anti-oxidants, thereby increasing activity of the oxidants. This surprising result was reported in Cancer Cell 27, 211–222, February 9, 2015. In an article entitled “Glutathione and Thioredoxin Antioxidant Pathways Synergize to Drive Cancer Initiation and Progression”. The jist of it is that cancers require certain anti-oxidant pathways to get started and progress. If these are inhibited, the oxidants will kill the cancer. This is kind of a very localized, targeted, chemo-therapy system.

This does make some sense. In many tumors, the mitochondria are very dysfunctional, and might reasonably be expected to spew quite a lot of oxidants into the host cell. Without a nice anti-oxidant cleanup, these oxidants might well kill the cancerous cells.

It appears that to successfully kill cancer cells, two cellular anti-oxidant pathways need to be blocked. Thus the therapy would consist of blocking both anti-oxidant pathways, in hopes that this would kill the tumor. Though the authors do not say so, we suppose that excernal anti-oxidants would be quite unwelcome in this scenario.

So far this seems to work in mice, so clinical use is some years away. If it holds up for humans, it could be a significant breakthrough. There are not many therapies that are effective against established tumors.

If it does work, it is going to be amusing to watch how the drug industry explains things. Here after decades of going after those nasty evil reactive-oxygen-species free radicals, they were actually killing cancerous tumors.

And we do fervently hope that the supplement industry will refrain from offering a pill that increases oxidants. Free-radicals in a jar? No thanks.

PS Cyanide is one of the most powerful anti-oxidants there is; it completely arrests aging.

  2 comments for “Antioxidants and Cancer

  1. Vinayak
    March 22, 2015 at 10:30 am

    I am slightly confused about the relation between multivitamins and antioxidants. Do vitamins themselves have antioxidant properties or do the multivitamin pill manufacturers add extra antioxidants to their pills?

    • March 23, 2015 at 10:48 am

      Both actually. If you read the label of the typical ‘multi-vitamin’ they are fairly good about making the distinction but the fact is there is no crisp distinction between the functions in every case. We were trying to make the general case about supplements per se and thus the same logic applies to almost every category. Supplements tend to be cyclic, in fact faddish, and you see different labels applied at different times. It looks like the current push is for hormone precursors to ‘boost’ one hormone or another. Dr. Mike

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