Medical Myths and the Popular Imagination I
"Everyone is entitled to their own opinion, but not to their own facts."
Sen. Patrick Moynihan
The Internet, more so than its media siblings, TV, radio, and print, has become our archipelago of medical misinformation. What we think we know merges imperceptibly into belief, and we are left with that slippery word "truth," be it revealing, liberating or subversive. Sympathy, according to Hume, edges into conformity, just as anger and frustration become fear. Fear of getting sick and obsession with health and illness-and death- become our daily preoccupations. Moreover, what most people believe about staying well and avoiding illness has become an established theology. Once any idea becomes accepted by the general public, it becomes frozen by habit and time, such that when it's proven wrong the "falsehood index" hardly declines. New evidence is ignored in the zeitgeist of immutable belief.
I am indebted to the comedian, Stephen Colbert, for introducing us to his term, truthiness-in the dictionary now-signifying imitation or ersatz truth, the appeal of raw feeling over proven reality. Ben Zimmer in the New York Times observes that the neologism has spawned numerous imitators ending in –iness-as in "fame-iness for Paris Hilton-style celebrity." We have become a society pistol whipped by medical Groupthink, polluted by nonsense masquerading as fact. Following are some personal choices. Call it one doctor's first hit list of truthiness.
Junk Science, Lies, and Fraud in the Medical Literature
An authoritative article by David H. Freedman, in the Atlantic Monthly Nov., 2010 observes that much of what medical researchers conclude in their studies is misleading, exaggerated, or flat-out wrong. The author's prime source is the internationally respected meta-researcher, Dr. John Ioannidis who has spent his career challenging his peers in biomedical research by exposing a majority of their conclusions in published studies as bad science. These conclusions powerfully influence doctors when they advise us to consume more fiber or less red meat, prescribe drugs or even recommend surgery for heart disease or back pain. Ioannidais charges that as much as 90 percent of the published medical information that doctors rely on is flawed.
I have quoted reports that new drug application studies with favorable outcomes were almost five times more likely to be published as those with unfavorable ones. 26% of pre-specified outcome measures were omitted from journal articles of new drug trials. Of the 43 primary measures not supporting efficacy, 47% were not included in the published results.
Analyses of other articles that showed significant publication bias, called "HARKing," is a nice way of describing research inflating the apparent effectiveness of new drugs. Is it indelicate to point out that cherry picking the results of drug trials is simply a form of lying? Vioxx, Zelnorm, and Baycol were among the widely prescribed drugs found to be safe and effective in large randomized controlled trials before the drugs were yanked from the market, sometimes years later, as unsafe, ineffective, or deadly. Look what's happening with Avandia, for eleven years, one of the world's leading drugs prescribed for type II diabetes. As one of the great physicians of the 19th Century, Sir William Osler once remarked "The first duties of the physician are to educate the masses not to take medicine." How times change.
The Atlantic article goes on to mention that medical-science "never minds" are rarely secret and usually go public. True, but these headlines tend to be dismissed or persistently ignored, as when a growing consensus of researchers concluded that mammograms, colonoscopies, and PSA tests are far less useful cancer-detection tools than we had been told, or when widely prescribed antidepressants such as Prozac, Zoloft, and Paxil were revealed to be no more effective than a placebo for most cases of depression. We drown in ever more myths. Last April, we were informed that taking fish oil, exercising, and doing puzzles doesn't really help fend off Alzheimer's disease, as long claimed. "Peer-reviewed studies have come to opposite conclusions on whether using cell phones can cause brain cancer, whether sleeping more than eight hours a night is healthful or dangerous, whether taking aspirin every day is more likely to save your life or cut it short, and whether routine angioplasty works better than pills to unclog heart arteries."
Can you Prevent Cancer or Live Longer with Fruits, Veggies, Diet and Exercise?
For the past few years the "battle against cancer" includes taking lots of fruits and vegetables-five servings a day-and ingesting vitamins, especially vitamin E and beta carotene, and the mineral selenium. But other measures that are often assumed-and marketed—as ways to prevent-cancer are either wrong-headed, unproven, or nonsensical according to researchers.
Fiber, found in fruits, vegetables and grains, has been touted to prevent colon cancer, even though two large studies found no effect. As for low-fat diets, long advertised to prevent breast cancer, a large federal study randomizing women to a low-fat or normal diet and looking for an effect in breast cancer found nothing.
Then there's exercise and weight loss, always a good bet to achieve longevity and glowing health. Studies have associated strenuous exercise with less cancer. But that is the same sort of phony evidence that misled scientists about aspects of diet. "I think it's wishful thinking," said Dr. Susan Love, cancer researcher and breast surgeon. "We would like to be more in our control. I think that's part of it. And in the absence of anything else, what do we tell women about how to prevent breast cancer? We tell them to exercise and eat a good diet."
Another study proposed would have been the largest cancer prevention clinical trial ever attempted, involving 35,000 men 50 and older. This time the idea was that vitamin E and selenium might prevent prostate cancer. The selenium and vitamin E study ended early, the antioxidant myth redux. Once again, there was no protection from cancer, and there were hints the supplements might be causing cancer. The great hope, after more billions spent on various scientific imaginings-$100 billion a year and rising-, again turned into profound disappointment. Other measures that are often assumed — and marketed — as ways to prevent cancer have never proven to make much difference, most researchers admit.
Are Carbs Are Bad for Your Health?
The low carbohydrate diet, basically a high fat diet which has been around since the 1860's, enjoyed an astounding re-awakening in the 1970's thanks to Dr.Robert Atkins, the diet martyr exposed for decades made billions on his diet (he died in 2003). But if one looks at the history of weight loss diets, other magic methods have recurrently captured the public imagination. So we have had low fat, high protein, low protein, high carb, high fat and other "miraculous" diets. Rarely mentioned is the low calorie diet. Moreover, every month brings an avalanche of outrageous fad diets-17.5 million sites on Google for the search term "diet." We have, among others,: the South Beach Diet, the Cheater's Diet, the Ornish diet, the Dr. Phil diet, the Shangri-La diet, the Banana diet, the Raw Foods diet, the Purge diet, etc., etc. Where does this leave Low Carbs and Atkins? Why do people continue embracing these false beliefs?
One false theory is that only carbohydrate in the diet will stimulate insulin production. The truth is that all ingested foods stimulate insulin production. The second false theory is that insulin stores fat only when high carbohydrate foods are eaten. See low carb Mania. The bottom line with regard to the body's biochemistry is that fat will only be stored if too much food (from any source) is eaten.
The Danish investigator, Professor Astrup analyzed the Atkins diet and assorted claims that low carbohydrate diets are effective for weight loss. In Astrup's exhaustively researched article, in The Lancet 2004; 364:897, he and his colleagues examined 2,609 articles on low carbohydrate diets, and found out of only 107 articles which could be reviewed. Only five studies evaluated participants for more than 90 days, but were not randomized and had no control group. Is the Atkins or low carb diet safe? Here is what Astrup had to say: "...restricted intake of whole grain bread and cereals, fruits and vegetables does not equal a healthy diet, and absence of these food groups may increase the risk of cancer and cardiovascular disease." Moreover, the low carbohydrate content of these diets is "below the minimum needed to supply the brain and muscles with sugar." Atkins dieters more often report muscle cramps, diarrhea, halitosis, general weakness, and rashes than those on a recommended low fat diet.
Calories Count, Carbs Don't
Finally, a recent lead article in the New England Journal of Medicine (360; 9, Feb.26, 2009) Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates compared 811 overweight adults to one of four low calorie diets of different composition. This is one of the most thorough and longest-term studies-two years- reported on the subject. Conclusion: "Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize." In other words, for weight loss Calories Count, not the percentage of fat, protein, or carbohydrates in your diet.
If only people understood more about the fallibility of medical science –especially clinical studies and the wrongness problem, they might be more skeptical. But medicine is not the only realm plagued with wrongness. Other experts have confirmed that similar issues distort research in all fields of science,-even physics-remember cold fusion? But other soft sciences from psychology to the social sciences, suffer from medicine's malady. Most dangerously we see this in economics where two highly regarded economists J. Bradford DeLong and Kevin Lang once showed how consistent scarcity of strong evidence in published economics studies made it unlikely that any of them were right.
Stay tuned for more on truthiness.
Martin F. Sturman, MD, FACP
Copyright 2010, Mathemedics, Inc.
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