Don't believe scare headlines about antioxidants and cancer risk

Step Right This Way!

Someone at Reuters Health apparently wants you to stop taking antioxidant supplements. Why? The reason seems clear. Just look at this recent Reuters headline: “Antioxidants more likely to raise cancer risk.”

There you go. You don’t want cancer, do you? Then don’t take antioxidants! Simple. Just one problem: This provocative headline is wildly misleading. It’s a seedy come-on, as false as the promise of a carnival barker in a low-rent circus.

Our annual tradition

It appears that about once each year we can expect some inflammatory reporting about the “dangers” of antioxidant supplements. And I’ve got a feeling that no matter how many years this goes on, it’s going to make me angry every single time.

The basis for this year’s absurd antioxidant attack is a study that appears in the January 2008 issue of the Mayo Clinic Proceedings. Mayo researchers conducted a meta-analysis of twelve clinical trials that tested antioxidant supplements against placebos in the prevention of cancer.

Let’s look at a three key quotes from the study:

1) “Antioxidant supplementation did not significantly reduce total cancer incidence or mortality.”

2) Selenium supplementation was associated with reduced cancer incidence in men but not in women and with reduced cancer mortality.”

3) “Beta carotene supplementation was associated with an increase in the incidence of cancer among smokers and with a trend toward increased cancer mortality.”

So let’s say you’re a headline writer for Reuters Health. How do you read those findings and come up with a blanket statement like: “Antioxidants more likely to raise cancer risk”?

Sure, beta-carotene supplementation is linked to higher cancer risk among smokers – we’ve known that for some time now. But whenever this link is “rediscovered,” beta- carotene is made out to be the culprit, as if cigarette smoking were some kind of harmless hobby with no negative effects.

Smokers need to be aware of this link, obviously. But anyone who believes that beta- carotene is the root cause of “a trend toward increased cancer mortality” is smoking something other than cigarettes.

Eat a peach

The Mayo Clinic web site notes that the adverse effects of beta-carotene “do not appear to occur” in smokers who eat foods high in beta-carotene content. Hmm. The adverse effects “do not APPEAR to occur”? That’s a roundabout way of saying, “We have no clue.” So, to be on the safe side, should smokers avoid dietary sources of beta-carotene?

The best sources of beta-carotene are dark orange, dark yellow, and dark green vegetables. Socarrots, spinach, and peaches – should these be taken off the smoker’s shopping list? Or should the cigarettes get pitched in favor of antioxidant-rich foods?

(I won’t pester smokers. I used to be one of them. When it comes down to a choice between a peach and a cigarette, they know which one will do them good and which will increase their cancer risk.)

In addition to noting that selenium supplements were linked to a 23 percent lower risk of cancer among men, the Reuters Health article also states (toward the bottom of the piece) that vitamin E supplementation was linked to a slightly lower risk of prostate cancer. So a perfectly accurate headline would have looked like this: “Antioxidant supplements may lower risk of some cancers.”

Now how easy was THAT!?

Meanwhile, the negative and inaccurate headline was distributed by news outlets around the world, convincing who knows how many readers that daily supplements might cause cancer.

Absurd. As usual. And Reuters Health editors should certainly know better.

“Efficacy of Antioxidant Supplementation in Reducing Primary Cancer Incidence and Mortality: Systematic Review and Meta-Analysis” Mayo Clinic Proceedings, Vol. 83, No. 1, January 2008,
“Antioxidants More Likely to Raise Cancer Risk” Reuters Health, 1/30/08,