Cancer Can Kill You (If you smoke, eat at McDonalds, live in Africa or eat broccoli...

Bruce Ames, a US epidemiologist plain talks on the real sources of human cancers.

If you asked all the world’s leading epidemiologists who’ve studied the subject, they’d come up with about the same list. Smoking is about a third of cancer, bad diets are another third of cancer, chronic infections, mostly in poor countries, hepatitis and schistosomiasis, all sorts of things like that. Helicobacter in your stomach, as we heard, about 20 percent. Hormones cause a lot of cell division and all of that, responsible for breast cancer, eudiometrical cancer. Occupation, a few percent.

And pollution, the numbers vary. It’s all a guess, but it isn’t much, and this less than one is my own estimate, and mostly heavy air pollution. But this is where we’re spending all the money by orders of magnitude. So something’s wrong if we’re putting our money on minor hypothetical risks and the major risks are not attended to.

So, while we heard about the big cancer epidemic, there really isn’t any cancer epidemic, other than due to smoking. If you look at cancer attributed to smoking, it’s going up, but if you look at cancer not attributed to smoking, it’s been going down. In fact, it’s been going down for a long time. So, there isn’t a cancer epidemic other than that due to smoking, this 30-year delay after people smoke.

And while we are at it, almost all "healthy" food (brocolli for example) is full of carcinogens. There are more carcinogens in one cup of coffee than in all the pesticide residues that a person consumes in a year.

Sensible plain talking. I work in the pollution management field, which is driven by the very minor risks he talks about, while the major risk factors are largely ignored. Let's really ban smoking and really do something about bad diets. If all the energy spent regulating air emissions were spent on reducing the real triggers for cancer, then perhaps progress could be made. But then there are too many people in the world anyway.