In the second half of the 20th century, conventional wisdom in the medical community held that overconsumption of saturated fats – the kind found in milk, cheese, meats and butter – was dangerous. And so, between 1968 and 1973, a well-planned, well-executed study involving more than 9,000 patients was performed to test this widely accepted relationship between diet and heart disease.
The results of the Minnesota Coronary Experiment were notable for two reasons. First, the findings contradicted much of what was believed at the time: The study demonstrated that people who ate a diet rich in saturated fats did not go on to have more heart disease than those who ate a diet rich in polyunsaturated fat from vegetable oil.
Second, and perhaps more important, these iconoclastic findings went unpublished until 1989 and then saw the light of day only in an obscure medical journal with few readers. One of the principal investigators told a science journalist that he sat on the results for 16 years and didn’t publish because “we were just so disappointed in the way they turned out.”
The long-forgotten study was revisited with a recent analysis of the original data and published this month by the National Institutes of Health in the prestigious, and well-read, British Medical Journal.
The Minnesota study is certainly not the last word on the subject, and its findings are already questioned by some of today’s researchers. The complexities of how much saturated fat in the diet is harmful will be debated for years to come.
But the companion issue raised by the Minnesota study is why such a rigorous experiment was essentially buried from public view for so long. That question asks as much about the scientific process as the study does about diet.
The primary researchers have been dead for years so they can’t elaborate on their reluctance to publish data that defied conventional wisdom. That reluctance suggests an explanation common to scientific journals – the resistance to new studies that go against the grain of established medical belief. A scientist’s career may be irreparably harmed by publishing studies that contradict accepted hypotheses. Add to this, journal editors and reviewers who approve publication may have a vested interest in these same accepted hypotheses.
All of this poses the danger that there may not be enough skeptical science in the medical and scientific literature. Groupthink may be as dangerous to the public as the ever-expanding legion of scientific frauds, quacks and celebrities eager for publicity or a quick buck.
Studies that challenge scientific consensus are not necessarily right – more often than not they are wrong – but they’re essential to good scientific method and occasionally result in a remarkable surprise. For decades the cause of stomach ulcers was believed to be excess stomach acid. Countless surgeries were performed to treat ulcers based on that theory.
In the 1980s, two scientists challenged that conventional wisdom and published research that said most stomach ulcers were due to a bacterium. The two researchers met resistance from the medical community for years, but their theory was borne out and they won the 2005 Nobel Prize in Medicine. Surgeons today no longer make their living solely by operating on stomach ulcers.
A noted scientific contrarian, Stanford professor John Ioannidis, pointed out recently in the Journal of Clinical Epidemiology, “Science is not about vote counting and signing petitions, it is (or should be) about evidence and its cautious interpretation.” About skepticism too:
As the Minnesota Coronary Experiment attests, scientific authority shouldn’t be immune from iconoclastic scientists or unconventional ideas. Albert Einstein’s view: “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.”