I must say, I don't blame the public for being annoyed--or scared--by the media coverage of the recent study that announced that eating red meat or bacon can increase your risk of getting cancer. Some articles went so far as to say you can put these foods in the same category as tobacco. And some medical sites are having a field day scaring the public with the new information.
These data come from retrospective epidemiological studies, which are notoriously difficult to carry out because they rely on people's memory of what they ate or drank years ago. And while some studies, like the current ones, do show an association between these foods and cancer, it is only with regard to one type of cancer--colon cancer--not all cancers.
Furthermore, to lump bacon and red meat in with tobacco is misleading and, frankly, ludicrous--maybe even harmful. If you make a bar graph of different lifestyle factors plotted against the risk of getting cancer, the smoking bar would tower over the others. If you smoke and eat a lot of red meat and bacon and decide to quit smoking but keep your diet the same, your risk of getting a whole bunch of cancers will decrease dramatically. If, however, you stop eating red meat and bacon, but keep smoking, you will not see any decrease in your risk of dying of cancer. This is called the relative risk.
While, from a public health perspective, it is useful to encourage people to eat a healthy diet, the advice needs to be put in perspective. People enjoy eating. And if you expect them to respond to advice you need to temper the advice to take enjoyment and relative risk into account.
Here's another example of why you need to temper your advice. In the early 1980s I was at an international cancer meeting in Seattle, Washington when an article was published in the New England Journal of Medicine, a prestigious medical journal. The article was by Brian McMann, a well known epidemiologist. And it showed that drinking a lot of coffee increased the risk of getting pancreas cancer.
The press ran with it, and a real panic set in. I was director of the National Cancer Institute then and the Reagan White House called me and asked me what my position was. I said I thought the conclusion was flawed. They asked if I would hold a press conference and say so. It so happens I was asked to go on a morning TV show and talk about it. I walked out on the set with a mug of coffee in my hand. That made the point.
No subsequent study ever confirmed the association of coffee with pancreatic cancer. I used to joke with my staff that any study reporting an association of a lifestyle factor and cancer should be kept in a vault until a second study on the same subject became available to confirm or deny it. That won't happen, of course. But those of us in the medical profession who are called on to interpret these kinds of results for the public should proceed with caution.
Doctors who are called upon to speak to the media often want to rush to give people vital data to save their lives. But what they end up doing, often, is scaring people so much they stop listening.