Miércoles 15 de Marzo de 2006, Ip nº 144

Food News Blues
Por Barbara Kantrowitz and Claudia Kalb

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."

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 WHI study is the latest in what appears to be a series of dietary flip-flops. 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. We've even been reading that chocolate could be a health food. (We've got some bad news on that. Read on.) Meanwhile, Americans are getting fatter and fatter. Two thirds are overweight or obese, and we're shelling out millions annually in a futile effort to shed those excess pounds.

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. Last year, 10 out of 50 NEWSWEEK cover stories were on such health issues as lung cancer, autism and heart disease. The WHI fat story led the TIP SHEET section in our Feb. 20 edition.

The pharmaceutical industry, wise to this proliferation of outlets and heightened consumer interest, spent $1.3 billion in magazine advertising last year, according to TNS Media Intelligence, a media-tracking service. An additional $2.4 billion went to network and cable TV.

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).

Some studies, like the WHI, are prospective, which means a group of patients is watched from the beginning of a treatment, procedure or intervention. Others are retrospective: they look back at patient records to uncover hints about disease onset or patterns. Still others are "meta-analyses," overviews of existing studies on a similar theme. Even bad studies can get published in journals with less rigorous standards. "The media reports all studies as if they have the same degree of certainty," says Dr. Elias Zerhouni, director of the National Institutes of Health. "There's no real label of quality."

To really understand what's going on, you also have to follow the money. The government pays for much of basic science, but industries with a stake in the outcome often fund food and drug studies. An industry connection doesn't necessarily mean a study is wrong. Scientists have to rely on different sources of support in the increasingly ferocious battle for dollars. But, says Dr. Richard Deyo, professor of medicine at the University of Washington in Seattle, "when corporate sponsors fund research, it's more likely to show beneficial effects." For example, industry-funded studies have consistently concluded that soda can be part of a healthy diet. But non-industry studies find that sugary beverages contribute to obesity. The National Dairy Council pays for research on the link between dairy food and weight loss. The California Raisin Marketing Board underwrote a study showing that raisins fight oral bacteria. If raisins hadn't done the job, the public might never have known. Industry-funded studies with negative results are often not published.

The stars in this vast medical-research universe were perfectly aligned in the early 1990s, when the WHI began. Women's health advocates had been pushing for more research. The NIH had its first female director, Dr. Bernadine Healy. And there were serious questions about older women's health that needed answers. Observational studies, which follow people over time without intervening in their behavior, had suggested that estrogen might prevent heart disease; millions of women were urged to take it. Scientists also decided to study the role of a low-fat diet and the use of calcium and vitamin D supplements to protect against fractures from osteoporosis. Together, heart disease, breast cancer and osteoporosis represent major causes of death and disability in older women. Preventing these diseases could affect millions.

The WHI was a massive undertaking—the largest federally funded study of women's health, ultimately costing $725 million over 15 years. In the early to mid-1990s, WHI researchers recruited 161,808 women age 50 to 79 from all over the country. This in itself was a major achievement because joining the study was a serious commitment. The women had to agree to be tested regularly, fill in lots of forms, take medication without knowing whether it would help them or hurt them, and, in the case of the dietary study, learn to cook and eat in a completely different way.

From the beginning, the WHI was controversial. Scientists especially questioned the diet trial, which enrolled 48,835 women. Psychologist Kelly Brownell, director of Yale's Rudd Center for Food Policy and Obesity, was on a committee convened at the request of Congress in 1993 to review the WHI. He says committee members were concerned about the design. Cancer and heart disease can take decades to develop. Would an eight-year trial be long enough? Would the women in the test group fully report their eating habits? Self-reports of dietary intake are notoriously inaccurate. On average, the participants weighed 170 pounds at the outset and reported that they ate 1,700 calories a day. By the end, they reported eating 1,400 to 1,500 calories daily. "They should have lost loads of weight," says Brownell. "Yet the women in the test group only lost three or four pounds. The control group actually gained about a pound. A scale is a scale. It won't lie. That screams out to me that the dietary records were inaccurate." It could mean that the difference in fat intake between the test and control groups wasn't large enough to show a distinct effect.

The calcium and vitamin D study also had its critics. When it was designed, calcium was considered so important that researchers thought it would be unethical to tell women in the control group to stop taking supplements. In the end, the test subjects and the placebo group were both taking in roughly the same amount of calcium. So when the final results showed little difference in the fracture rate between the two groups, some scientists blamed the study design. And there was a second problem. The amount of vitamin D they were given is considered inadequate today. Most doctors still recommend calcium supplements if women can't get enough in their diets. "It was a disappointment that it was not better designed," says Joan Lappe, professor of medicine at the Osteoporosis Research Center at Creighton University. She and her colleagues are worried that the public is getting the message that calcium and vitamin D don't matter.

WHI investigators fired off their first bombshell in 2002, when they stopped the hormone study early after a safety-monitoring board concluded that the risks outweighed the benefits. Gynecologists' phones rang off the hook as millions of patients demanded to know if they'd been duped. That study continues to be a source of fierce debate. Although the results showed an increased risk of breast cancer, stroke, blood clots and heart disease in women who took estrogen and progestin, some scientists say the reaction was too strong. Many doctors believe younger women who take hormones for a short time to relieve menopausal symptoms like hot flashes are generally at low risk. There's also some evidence that estrogen might protect younger women against heart disease. Researchers are only beginning to study that issue.

Years ago this debate would have been confined to scientific circles. Medical journals would have filtered new research and doctors would have read the journals, discussed studies with colleagues and then figured out how to translate data into clinical practice. All this was hidden to patients. Now even the most respected journals have had to adapt to the growing demand for health information. When The Journal of the American Medical Association (JAMA) and The New England Journal of Medicine were launched in the 19th century, they would have had no conception of a "publicity" department. But today, JAMA, which has published several WHI studies, spends $1 million annually on its media and communications program, says Dr. Catherine DeAngelis, the editor. Half goes to packaging video interviews, which TV reporters use in their stories. DeAngelis says the JAMA footage hits an average of 20 million viewers a week through local, national and international outlets. The other half of the money is used to run the communications office, hold press conferences and prepare press releases about upcoming studies, which reporters receive before the studies are published—if they tacitly agree not to print anything before the journal's publication date. If they agree to these "embargo" terms, they can question the scientists involved in the study and others who might have a more objective view of the research.

All that was in place last month when the WHI released its diet study. The headline in the main JAMA article, published on Feb. 8, gave no hint that some readers might be tempted to head for Krispy Kreme: LOW-FAT DIETARY PATTERN AND RISK OF INVASIVE BREAST CANCER. Two other articles in the same issue discussed the impact of the diet on heart disease and colorectal cancer. Like any journal report, all three were laden with details, including the number of women in the trial (48,835) and the goals (to reduce fat to 20 percent of calories and to increase consumption of vegetables, fruit and grains). The conclusion of the breast-cancer study—that a low-fat diet did not lower risk—was fairly nuanced. It suggested that if the women were observed for a longer time, there might be more of an effect. At a conference last week at the National Institutes of Health, which sponsors the WHI, researchers were even more direct, saying that they hoped women would not start eating fat because of this study, but that message got lost in the headlines.

The diet study was a victim of its time. Fifteen years later, we know a lot more and understand that some fatty foods, like olive oil and avocados, may actually be beneficial. And some food labeled fat-free is full of calories, which might have accounted for some of the participants' weight issues. "These studies are more complicated than a simple headline or sound bite can convey, and that's an important lesson for all of us," says Dr. Elizabeth Nabel, director of the National Heart, Lung, and Blood Institute, which administers the WHI.

But to the average American, the WHI study just seemed like one more example of scientists unable to make up their minds. Dr. Mary Altz-Smith, a rheumatologist in Birmingham, Ala., is worried about the message it sent to her patients, many of whom are already overweight. "This information is all too likely to encourage patients to slide," she says. And who could blame them? Every day, the "truth" about diet seems ever more elusive even while scientists insist the picture is becoming clearer. A classic case is margarine. Early on, it was touted to be better than butter, which contains saturated fat. But that was before scientists realized that margarine had an even more noxious ingredient: trans fat. Margarine became poison. Now the pendulum has shifted back a bit as manufacturers removed the bad fat and put in nonhydrogenated oils. "Those are better," says Dr. Walter Willett, chair of nutrition at the Harvard School of Public Health. "But it's still better to use liquid vegetable oils, like olive oil." And as for butter, the fact that margarine was worse doesn't make butter good. "It's not health food," Willett says.

More recently, chocolate appeared to be heading for that coveted health-food status, and the public was more than ready to gobble it up. It began when a 2001 study (funded by the American Cocoa Research Institute) found that cocoa powder and dark chocolate boosted good cholesterol by 4 percent. What most people didn't realize is that there were only 23 participants in this study, hardly enough to produce any serious conclusion. Nonetheless, it made headlines and was followed by additional chocolate studies that seemed to find even more benefits. But most of that research focused on a group of compounds in chocolate called flavanols—which unfortunately tend to get processed out of the chocolate you buy at the grocery store. And chocolate still has lots of fat, sugar and calories.

Just last week a study from the Netherlands published in the Archives of Internal Medicine found that participants who ate the most food containing chocolate (candy bars, spreads, pudding) had slightly lower blood pressure and were half as likely to have died from heart disease at the end of the 15-year follow-up. However, it's not clear that the results were strictly from chocolate. The biggest challenge in dietary research is that nobody eats only one thing. In this case, the chocolate lovers also ate less meat and more nuts. "This study is another piece of the puzzle," says Harold Schmitz, chief science officer of Mars Inc., the candy manufacturer. "As much as I'd love to say it puts the capstone on the research, it doesn't." And it could be years before there's a definitive answer.

Everyone's looking for an immediate solution, but science takes time. It took Judah Folkman decades to confirm his pioneering theory that cancerous tumors rely on a blood supply to grow. When The New York Times heralded his research on the front page with a headline that proclaimed HOPE IN THE LAB, TV, newspapers and magazines (including NEWSWEEK) picked up the story. Desperate patients flooded Folkman's lab with phone calls seeking help. But at the time, his research was only in mice, not men—a detail that many readers overlooked. It was years before Folkman's theory—called angiogenesis—translated into drugs that can actually help people. More than anybody, Folkman understands how difficult it is to balance enthusiasm for scientific progress with the danger of hyping new developments. "That's the fundamental problem," he says. "We scientists don't always know how to share our excitement with the public without making our research sound overdone."

It's even more complicated with a study like the WHI, which is paid for by taxpayers and is of enormous interest to a wide range of people. What may have seemed like flip-flopping is actually an evolutionary process, says Stanford's Marcia Stefanick, chair of the WHI steering committee. "As we acquire new scientific information, we need to modify public-health recommendations." If the diet results were misinterpreted, there's probably blame all around. Journalists wanted juicy headlines and the public wanted a quick fix for fat. Scientists were trying to report their findings in the most digestible form while acknowledging that reality was more complex. It would be nice to think that everybody is a little bit wiser. For all their differences, scientists and journalists are on the same path. They should keep asking questions, not be discouraged by dead ends and be open-minded to surprising truths.


  13/03/2006. MSNBC News.