By Gary Taubes, author of Nobel Dreams (1987), Bad Science (1993), Good Calories, Bad Calories (2007), and Why We Get Fat (2011). Taubes is a former staff member at DISCOVER. He has won the Science in Society Award of the National Association of Science Writers three times and was awarded an MIT Knight Science Journalism Fellowship for 1996-97. A modified version of this post appeared on Taubes’ blog.
The last couple of weeks have witnessed a slightly-greater-than-usual outbreak of extremely newsworthy nutrition stories that could be described as bad journalism feasting on bad science. The first was a report out of the Harvard School of Public Health that meat-eating apparently causes premature death and disease (here’s how the New York Times covered it), and the second out of UC San Diego suggesting that chocolate is a food we should all be eating to lose weight (the Times again).
Both of these studies were classic examples of what is known technically as observational epidemiology, a field of research I discussed at great length back in 2007 in a cover article for in the New York Times Magazine. The article was called “Do We Really Know What Makes Us Healthy?” and I made the argument that this particular pursuit is closer to a pseudoscience than a real science.
As a case study, I used a collaboration of researchers from the Harvard School of Public Health, led by Walter Willett, who runs the Nurses’ Health Study. And I pointed out that every time that these Harvard researchers had claimed that an association observed in their observational trials was a causal relationship—that food or drug X caused disease or health benefit Y—and that this supposed causal relationship had then been tested in experiment, the experiment had failed to confirm the causal interpretation—i.e., the folks from Harvard got it wrong. Not most times, but every time.
Now it’s these very same Harvard researchers—Walter Willett and his colleagues—who have authored the article from two weeks ago claiming that red meat and processed meat consumption is deadly; that eating it regularly raises our risk of dying prematurely and contracting a host of chronic diseases. Zoe Harcombe has done a wonderful job dissecting the paper at her site. I want to talk about the bigger picture (in a less concise way).
This is an issue about science itself and the quality of research done in nutrition. Science is ultimately about establishing cause and effect. It’s not about guessing. You come up with a hypothesis—force x causes observation y—and then you do your best to prove that it’s wrong. If you can’t, you tentatively accept the possibility that your hypothesis might be right. In the words of Karl Popper, a leading philosopher of science, “The method of science is the method of bold conjectures and ingenious and severe attempts to refute them.” The bold conjectures, the hypotheses, making the observations that lead to your conjectures… that’s the easy part. The ingenious and severe attempts to refute your conjectures is the hard part. Anyone can make a bold conjecture. (Here’s one: space aliens cause heart disease.) Testing hypotheses ingeniously and severely is the single most important part of doing science.
The problem with observational studies like the ones from Harvard and UCSD that gave us the bad news about meat and the good news about chocolate, is that the researchers do little of this. The hard part of science is left out, and they skip straight to the endpoint, insisting that their causal interpretation of the association is the correct one and we should probably all change our diets accordingly.
Vincent Racaniello is Higgins Professor of Microbiology & Immunology at Columbia University, where he oversees research on viruses that cause common colds and poliomyelitis. He teaches virology to undergraduate, graduate, medical, dental, and nursing students, and writes about viruses at virology.ws.
The detection of a new virus called XMRV in the blood of patients with chronic fatigue syndrome (CFS) in 2009 raised hope that a long-sought cause of the disease, whose central characteristic is extreme tiredness that lasts for at least six months, had been finally found. But that hypothesis has dramatically fallen apart in recent months. Its public demise brings to mind an instance when a virus *was* successfully determined to be behind a mysterious scourge: the case of HIV and AIDS. How are these two diseases different—how was it that stringent lab tests and epidemiology ruled one of these viruses out, and one of them in?
David Ropeik is an international consultant in risk perception and risk communication, and an Instructor in the Environmental Management Program at the Harvard University Extension School. He is the author of How Risky Is It, Really? Why Our Fears Don’t Always Match the Facts and principal co-author of RISK A Practical Guide for Deciding What’s Really Safe and What’s Really Dangerous in the World Around You. He writes the blog Risk; Reason and Reality at Big Think.com and also writes for Huffington Post, Psychology Today, and Scientific American.
He founded the program “Improving Media Coverage of Risk,” was an award-winning journalist in Boston for 22 years and a Knight Science Journalism Fellow at MIT.
This post originally appeared on Soapbox Science, a guest blog hosted by the nature.com Communities team.
If you were to be diagnosed with cancer, how do you think you would feel? It would depend on the type of cancer of course, but there’s a good chance that no matter the details, the word “cancer” would make the diagnosis much more frightening. Frightening enough, in fact, to do you as much harm, or more, than the disease itself. There is no question that in many cases, we are cancer-phobic, more afraid of the disease than the medical evidence says we need to be, and that fear alone can be bad for our health. As much as we need to understand cancer itself, we need to recognize and understand this risk, the risk of cancer phobia, in order to avoid all of what this awful disease can do to us.
In a recent report to the U.S. National Institutes of Health (NIH), a panel of leading experts on prostate cancer, the second most common cancer in men (after skin), said;
“Although most prostate cancers are slow growing and unlikely to spread, most men receive immediate treatment with surgery or radiation. These therapeutic strategies are associated with short- and long-term complications including impotence and urinary incontinence.”
“Approximately 10 percent of men who are eligible for observational strategies (keep an eye on it but no immediate need for surgery or radiation) choose this approach.”
“Early results demonstrate disease-free and survival rates that compare favorably (between observation and) curative therapy.”
“Because of the very favorable prognosis of low-risk prostate cancer, strong consideration should be given to removing the anxiety-provoking term ‘cancer’ for this condition.”
Let me sum that up. Many prostate cancers grow so slowly they don’t need to be treated right away…the unnecessary treatment causes significant harm…and one of the reasons nine men out of ten men diagnosed with slow-growing prostate cancer accept, indeed choose these unnecessary harms, is because “cancer” sounds scary.