The dietary mess

All fat was bad; now some fat is good. Eggs were bad; now they're OK in moderation. Nuts were verboten; now their fats are beneficial. Coffee has been up and down more often than hemlines.

Not surprisingly, to those of us without an M.D., it sometimes seems as if scientists are deliberately trying to mess with our heads—especially when it comes to nutrition research. The dietary flip-flop by doctors, scientists and nutrition specialists has the entire world confused. Newsweek has an interesting cover story on how the contradictory information about the qualities of some of the food we eat everyday has actually foxed the humanity. I am copy-pasting part of the story before it goes behind the subscription wall of the Newsweek.

You couldn't miss the headlines. The New York Times: LOW-FAT DIET DOES NOT CUT HEALTH RISKS, STUDY FINDS. The Atlanta Journal-Constitution: REDUCING FAT MAY NOT CURB DISEASE. The Boston Globe: STUDY FINDS NO MAJOR BENEFIT OF A LOW-FAT DIET. The Los Angeles Times: EATING LEAN DOESN'T CUT RISK. When the results of a massive, federally funded study were released last month, TV, newspapers and, yes, magazines around the country trumpeted what seemed to confound conventional wisdom and standard medical advice. Fat, these articles seemed to say, wasn't so bad for you after all. In fact, the results of the study, the Women's Health Initiative (WHI), were actually more complex—as all these articles explained to readers who got beyond the headlines.

It wasn't (as many of us might have hoped) a signal to rush out and gorge on cheeseburgers—especially if you're a man of any age or a woman under 50. That's because the study involved only older women—from 50 to 79. And the primary goal was far narrower than those headlines implied: to test whether cutting fat would reduce the risk, specifically, of breast cancer. After an average of eight years, researchers found no statistically significant difference in breast-cancer risk between women on a low-fat diet and women who had made no changes in what they ate. But that is not the bottom line. The results showed what researchers call a "trend" toward a low-fat diet reducing breast-cancer risk; this effect was actually significant in those who started with the highest levels of fat. Scientists will observe the women until 2010, when we could hear a whole new message. "I wouldn't worry about the headlines of today as far as low fat and breast cancer are concerned," says Dr. Jacques Rossouw, the WHI project officer. "They may be wrong."

Why all the mixed messages? Three words: too much information. Not so long ago patients got all their medical knowledge from their doctors. But now a media explosion has transformed that intimate relationship into an orgy of Web sites, cable- and network-TV medical reports, and magazine and newspaper stories heralding one breakthrough after another. Americans are more likely to hear first reports of the latest cancer treatment from CNN's Sanjay Gupta or ABC's Tim Johnson (both doctors) than from their own oncologist. From 1977 to 2004, the number of newspaper front-page stories on science tripled, from 1 to 3 percent, while foreign-affairs coverage plummeted from 27 to 14 percent, according to the Project for Excellence in Journalism, a group that monitors media coverage. In news magazines, the number of pages devoted to health and medical science has quadrupled since 1980.

Scientists themselves have become part of the media machine. In the old days, researchers who went public with their petri dishes were scorned by colleagues. Some still are. But the pressure to talk to reporters is enormous. Hospitals and universities send out press releases and publish glossy magazines about scientific advances within their ranks to generate buzz and maybe even research dollars. Drug companies hire physicians as consultants, then tout them as experts, setting up interviews with reporters about developments in a disease when the real motive is to promote a drug. And then there are the truly aggressive doctors—many of them in fields like dermatology and plastic surgery, where they are vying for patients—who hire their own public-relations reps who then mail press kits to reporters, complete with 8-by-10 photos. Even the most guarded scientists know that it's hard to hide, especially if their research is being paid for by the taxpaying public. They may seem like geeks in lab coats, but scientific research is hugely competitive—for attention, recognition and funding. The most egregious example: the South Korean stem-cell debacle. A supposed milestone in the controversial science—cloning human embryos to create stem cells—turned out to be a fraud. "Science is a contact sport," says Dr. Jeffrey Drazen, editor of the prestigious New England Journal of Medicine. "People think about it being genteel, but it's a tough game."

All this coverage would be fine, perhaps even beneficial, if medical progress were as straightforward as it's often reported. Unfortunately, it's not. Headlines and sound bites can't capture the complexity of research. Science works in small steps, and failure and mistakes are an integral part of the process. Experiments flame out; hypotheses crash and burn. "Most science isn't a breakthrough," says Dr. Judah Folkman, the famed cancer researcher at Children's Hospital Boston who was involuntarily thrust into the spotlight by a 1998 New York Times story about his research. "It's incremental, brick by brick." But the public has big expectations. "Science and medicine have promised a lot," says Dr. Jerome Groopman of Harvard Medical School and a writer for The New Yorker. "We have all this technology, this information and resources, and we're making promises to people. In many cases, we still don't have the answers."

Published studies on the same topic can vary enormously in terms of sample size (small, medium, big), demographics (age, gender), data (self-reported versus objectively measured information) and length (weeks, months, years). Then there's the design of the study, a critical factor. The gold standard, a randomized, double-blind, placebo-controlled trial, is considered the most reliable because neither researchers nor participants know who is taking the medication being tested and who is taking the placebo (essentially a sugar pill).