Evidence that Antioxidants Increase Cancer

Many researchers were shocked when a large 1984 experiment found that a beta-carotene supplement increased lung cancer. Because beta-carotene is a potent antioxidant, and epidemiology had linked eating vegetables with less cancer, it was supposed to decrease lung cancer. My Berkeley neighbor Bruce Ames was the foremost proponent of the idea that antioxidants will decrease cancer.

Now more evidence supports the idea that antioxidants may increase cancer.

A request for comment elicited this:

“It’s disappointing but not surprising that people’s beliefs are not modified by scientific evidence,” said Dr Paul Marantz, an epidemiologist at Albert Einstein College of Medicine in New York. “People so want to believe there is a magic bullet out there.”

One commenter on the article rightly says:

“It’s disappointing but not surprising that people’s beliefs are not modified by scientific evidence,” . . . Rather a snide comment considering the fact that it was science that spent years telling everyone that antioxidants and supplements were beneficial.


12 Replies to “Evidence that Antioxidants Increase Cancer”

  1. Snide, maybe, but it does not get around the larger effect: that people want to rely and believe what “experts” say. It is easy to blame an “expert” or use them as scapegoats when things turn out to be wrong than it is to take responsibility for it.

    That is exactly what personal science/self-experimentation avoids. It puts the responsibility back with the individual.

    Hindsight is always 20/20.

  2. The study seems to have found that the antioxidants are too much of a good thing.

    From the article: “What seems to happen is that antioxidants indeed decrease DNA damage, as expected. But the damage becomes so insignificant as to be undetectable by the cell. The cell therefore does not deploy its cancer-defense system …”

  3. I think the best argument for being careful with antioxidant intake came from sports medicine. I want to work out and get the benefits of working out and I could see how antioxidants might impede the process. But the first thing I thought of when I clicked on this link was, were they using real vitamin E or that fake stuff? And soy free vitamin E products are hard to find, so there’s another confounding factor.
    So, this sort of study makes me think nobody can patent antioxidants and cancer seems to be quite lucrative for the medical industry, regardless of whether or not the patient eventually dies, so I need to be careful believing these results.

  4. It’s important to note that this does not apply to food:

    “The scientists stressed that the results do not pertain to foods such as fruits and vegetables that are naturally high in antioxidants.”

    One could hardly eat enough of some of these high antioxidant foods (although I can demolish the cacao and Okinowan Purple Yams) for them to be harmful. As with much consumption, there seems to be a U-shaped curve.

    Further, there are plenty of other benefits attributed to antioxidants that go beyond whatever previous cancer prevention benefits were assigned to them.

  5. This is hindsight, but I wonder if there were ways to tell tat antioxicidants didn’t have a good enough theory behind them.

    There was no detail or quantification. How much of which antioxicidants?

    Perhaps more importantly, there was no feedback– no hint of how you could tell whether you were taking too much of something.

  6. If you’ve been keeping up with Mr. Heisenbug and the other gut biota bloggers, this would not be surprising. The cancer-fighting effect from vegetables is likely not from feeding anti-oxidants to ourselves; rather, it’s from feeding soluble fiber to our gut bacteria. They found a correlation and jumped to a causation.

    Well, in their defense, I’m sure it sounded good at the time.

    Seth: good point. yes, there is a long history of jumping to conclusions in nutrition.

  7. Agree with William,
    “It’s important to note that this does not apply to food”
    “As with much consumption, there seems to be a U-shaped curve”

    When looking at/thinking about taking a new supplement, i always think, how much food would i need to eat to get that particular dose of vitamin/mineral etc…& is that feasible or would that have been feasible in the past…

    Take astaxanthin as an example, plenty of hype around this one in recent years, especially over at mercola.com (who sells it), with info like “550 times stronger than vitamin E, and 6,000 times stronger than vitamin C” as per the ORAC values (purportedly).

    the mercola product contains 4mg of astaxanthin per capsule, dose one per day.
    & on his web site he talks about doses up to 12mg per day for certain ailments.

    even 4mg is a lot of Haematococcus pluvialis (MicroAlgae) even if you happen to have access to some…and even more shrimp & krill.

  8. …& you need to eat the complete shrimp/krill, shells & heads to get the astaxanthin (but that would have been how our ancestors would have eaten them i assume, no wimpy peeled & beheaded shrimp)

  9. Superfood supplementation, right on up to vitamins, minerals and hi-tech isolates are not exempt from the rule of ‘iatrogenics’ in that they all help us compensate for the imbalances caused by lifestyle without forcing us to correct the lifestyle.

    After all today’s medicines are the result of centuries of herbal medicine. Today’s pill poppers are little different from the pill poppers of yesteryear and of the next century.

    I continue to use my favourites, just the same. Will fix up the lifestyle just before the cancer gets me!

  10. It is unfortunate that the term “antioxidant” is not routinely preceded by the qualifiers “endogenous” or “exogenous”. While exogenous antioxidants are frequently sources of oxidative stress themselves (and the attendant increased rate of mutation), endogenous antioxidant enzymes are responsible for the evolution of aerobic life itself, and without them, no aerobic life-form can exist. It is becoming progressively more apparent to members of the medical community, as it has been to members of the biochemistry community for years, that activation of the Nrf2 master transcription protein, which controls the activity of the activity of the genes for endogenous antioxidant enzymes, may well be a giant step toward the prevention, and perhaps the treatment, of degenerative diseases. See Biogen’s recently FDA-approved Nrf2 activator, Tecfidera, for the treatment of multiple sclerosis. Ironically, the most potent Nrf2 activator yet tested is a combination of extracts from phytonutrients, which the FDA classifies as a “supplement”, putting it in the same category as the “worthless” compounds in recent government and medical publications.

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