Evidence-Based Medicine or Evidence-Biased?

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Dr. Esselstyn’s landmark study showing even advanced triple vessel coronary artery disease could be reversed with a plant-based diet has been criticized for being such a small study. But the reason we’re used to seeing such large studies is they typically show such small effects. Drug manufacturers may need to study 7,000 people in order to show a barely statistically significant 15% drop in ischemic events in a subsample of patients, whereas Esselstyn got a 100% drop in those who stuck to his diet—all the more compelling given that those 18 participants experienced “49 coronary events [such as heart attacks] in the 8 years before” they went on the diet. And these were the worst of the worst—most of whom having already failed surgical intervention. So, when the effects are that dramatic, how many people do you need?

Before 1885, symptomatic rabies was death sentence until July 6^th, when little Joseph Meister became the first to receive Pasteur’s experimental rabies vaccine. “The results of this [and one other] case were so dramatic compared with previous experience” that the new treatment was accepted with a sample size of two. So dramatic, compared with previous experience, no randomized controlled trial was necessary. “Would you—having been infected by a rabid dog—be willing to participate in a randomized controlled trial…when being in the control group had a certainty of a ‘most awful death’?” Sadly, such a question is not entirely rhetorical.

In the 1970s, a revolutionary treatment for babies with immature lungs called ECMO, extracorporeal membranous oxygenation, “transformed mortality in these [babies] from 80 per cent [down] to 20 percent, nearly overnight”—from 80% dead to 80% alive. Despite this dramatic success, they felt forced to perform a randomized controlled trial. They didn’t want to. They knew they’d be condemning babies to death. “They felt compelled to perform [such] a trial, because their claim that ECMO [worked] would, they judged, carry little weight amongst their medical colleagues unless supported by a [randomized controlled] trial.”

And so, at Harvard’s Children’s Hospital, 39 infants were randomized to either get ECMO or not—just get conventional medical therapy. They decided to stop the trial after the fourth death, so as not to kill too many babies. And, that’s what they did. The study “was halted after the fourth [conventional medical therapy] death,” at which point nine out of the nine ECMO babies had survived. Imagine being the parent of one of those four dead children—just as one can imagine being the child of a parent who died from conventional medical or surgical therapy for heart disease.

“Medical students in the United States are taught [very] little about nutrition. Worse yet, their training [actually] biases them against the studies that show the power of dietary approaches to managing disease,” by encouraging them “to ignore any information that does not come from…double-blind, randomized controlled trial[s]. Yet human beings cannot [easily] be blinded to a dietary intervention.” They tend to notice what they’re eating. As a result, physicians [may be] biased [in favor of] drug treatments and against dietary interventions for the management of chronic disease.”

“Evidence[-based medicine] is a good thing. However, the medical profession [may be] focusing too much on one kind of evidence, to the exclusion of [all] others”—degenerating into a “ignoring-most-of-the-truly-important-evidence[-based] medicine.”

And heart disease is the perfect example. On a healthy-enough plant-based diet, our #1 cause of death may “simply cease…to exist.” The Cornell-Oxford-China Study showed that even “small amounts of animal-based foods [was] associated with small, but measurable increases in [the] risk of [some of these chronic] disease[s].”

“In other words, the causal relationship between dietary patterns and coronary artery disease was already well established before…Ornish…and…Esselstyn…undertook their clinical studies. The value of their studies was not so much in providing evidence that such a dietary change would be effective, but in showing that physicians can persuade their patients to make such changes,” and also providing interesting “data on the speed and magnitude of the change in severe atherosclerotic lesions as a result of dietary therapy.”

So, “[a]ny complaints that these studies were small or unblinded are simply irrelevant. Because the evidence of the role of diet in causing atherosclerosis is already so overwhelming, assigning a patient to a control group [eating the Standard American Diet could be considered a] violation of research ethics.”

“Evidence of the value of…plant-based diet[s] for managing [chronic disease] has been available in the medical literature for decades.” Kempner at Duke; John McDougall; The Physician’s Committee for Responsible Medicine. “Denis Burkitt warned us” that the Standard American Diet “is the standard cause of death and disability in the Western world,” for decades. “Yet physicians,…in the [U.S.], are still busily manning the ambulances at the bottom of the cliff instead of building fences at the top.

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• C B Esselstyn Jr. Updating a 12-year experience with arrest and reversal therapy for coronary heart disease (an overdue requiem for palliative cardiology). The Am J Cardiol 1999 84(3):339 – 341.
• M Diaz, D Neuhauser. Pasteur and parachutes: When statistical process control is better than a randomized controlled trial. Qual Saf Health Care 2005 14(2):140 – 143.
• L E Thomas. How evidence-based medicine biases physicians against nutrition. Med Hypotheses 2013 81(6):1116 – 1119.
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• P P O'Rourke, R K Crone, J P Vacanti, J H Ware, C W Lillehei, R B Parad, M F Epstein. Extracorporeal membrane oxygenation and conventional medical therapy in neonates with persistent pulmonary hypertension of the newborn: A prospective randomized study. Pediatrics 1989 84(6):957 – 963.
• C B Esselstyn Jr. Resolving the Coronary Artery Disease Epidemic Through Plant-Based Nutrition. Prev Cardiol 2001 4(4):171 – 177.
• W Prasad, A Cifu. A medical burden of proof: Towards a new ethic. BioSocieties 2012 7:72 – 87.
• J Worrall. Why There’s No Cause to Randomize. Brit J Phil Sci 2007 58:451 – 488.
• Bartlett RH, Andrews AF, Toomasian JM, Haiduc NJ, Gazzaniga AB. Extracorporeal membrane oxygenation for newborn respiratory failure: forty-five cases. Surgery. 1982 Aug;92(2):425-33.

Images thanks to Wandering Eyre via flickr

• alimentación a base de vegetales
• dieta del arroz
• dieta occidental estándar
• Dr. Caldwell Esselstyn
• Dr. Dean Ornish
• Dr. Denis Burkitt
• Dr. John McDougall
• Dr. Walter Kempner
• El estudio de China
• enfermedad cardiaca
• enfermedad cardiovascular
• enfermedades crónicas
• formación médica
• infantes
• medicina del estilo de vida
• mortalidad
• Physicians Committee for Responsible Medicine
• productos de origen animal
• salud pulmonar
• vacunas